/ohm/ no girls allowed edition

[Anonymous No.1594926]

the old thread has reached the bump limit: >>1591072

>RULES
0. Electrics ≠ electronics. Home appliances/sparkies to /qtddtot/ or /sqt/. PC assembly to >>>/g/.
1. Do your own homework. Search web first. Re-read all documentation/datasheets related to your components/circuits. THEN ask.
2. Pics > 1000 words. Post relevant schematic/picture/sketch/9001.5 hours in MS Paint with all part numbers/values/etc. when asking for help. Focus/lighting counts.
3. Read posts fully. Solve more problems than you create.
4. /ohm/ is an anonymous, non-smoking general.

>I'm new to electronics, where to get started?
It is an art/science of applying principles to requirements. Find problem, learn principles, design and verify solution, build, test, post results, repeat

>Project ideas:
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Platt, Make: Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors
Horowitz and Hill, The Art of Electronics

>Design/verification tools:
LTSpice
falstad.com/circuit/circuitjs.html
NI Multisim
CircuitLab
iCircuit for Macs
KiCAD (pcb layout software, v5+ recommended)

>Components/equipment:
Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, especially good for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>Related YouTube channels:
mjlorton
jkgamm041
eevblog
EcProjects
greatscottlab
Photonvids
sdgelectronics
BigClive

>Li+/LiPo batteries
Read this exemplary resource first: https://www.robotshop.com/media/files/pdf/hyperion-g5-50c-3s-1100mah-lipo-battery-User-Guide.pdf
>I have junk, what do?
Take it to the recycler.

[Anonymous No.1594977]

>>1594685▶

I figured it out, spock, but here was the motivation for the question.

[Anonymous No.1595151]

I have a simple little i2c network setup with one master and 6 slaves
It works perfectly fine.

But, when a slave has no power and at least one (or both) of it's two data cables (sda and scl) are connected, the whole i2c network stops working until i connect the power back to that slave.
Pull ups are handled by the master.

Any idea what could be causing this?

[Anonymous No.1595156]

>>1595151
ESD protection diodes to Vcc on slave I2C inputs, probably

[Anonymous No.1595165]

>>1595156
>ESD protection diodes
Wouldn't that only be a problem if the i2c voltage is higher than whatever the breakdown voltage of that diode is? which it isn't

[Anonymous No.1595170]

>>1595165
no, they're plain diodes to Vss and Vdd that are reverse-biased in normal operation. the idea is that the power rails probably have lots of capacitance on them to absorb the charge pulse from an ESD event, far more than the logic gates themselves. in essence, the logic-high signals (via your pullups) are attempting to power the chip

[Anonymous No.1595171]

>>1595170
I see. So i could add a mosfet onto the data line which the slave turns on when its powered and allows bidirectional pulses to flow freely through it and if the slave has no power (so no power at the gate, since the gate will be wired directly to the rail), the mosfet will not conduct and have a massive resistance, thus making it as if the wire is disconnected

[Anonymous No.1595179]

>>1595171
yeah, an N-MOSFET with drain toward the bus and gate tied to slave V+ would probably do, but you'd need to add a large pull-down resistor on the inside of the FET, and hope you haven't got too many slaves on the bus at once lest they overpower your bus pullup
I have seen analog switches designed to handle hot-plugging which will probably have defined and far better leakage specs, but I don't have any part numbers to hand

[Anonymous No.1595205]

>>1595179
Got one more thing, the master is 3.3V and the slaves are 5V, but since the master is handling the pull ups and I2C only ever pulls the lines down, never high, this shouldn't be a problem right?

[Anonymous No.1595478]

what is that cumshot thing people squeeze out all over smd components and then melt it with hot air until the components start to move?

[Anonymous No.1595480]

>>1595478
flux

[Anonymous No.1595483]

>>1595205
>voltage translation
that's a problem you should have stated at the beginning. now you need a level shifter too, and of a kind that will isolate both sides without dragging them down when either side is powered down
this is the chip for that. the only major change you would have to make is to give it power from the master side

[Anonymous No.1595524]

Welcome to /diy/'s very own /ohm/ electronics general thread!!!

enjoy your stay while you check those digits
[thread brought you by Maxim - OVP controllers]

[Anonymous No.1595632]

How do I git gud at assembly? Even when I have logically sound code it doesn't work just because

[Anonymous No.1595641]

>>1595632
make sure you're using the peripherals correctly
start by messing around with known good code by someone else
refine your notion of logical soundness

[Anonymous No.1595647]

>>1595632
Compile something simple and study the intermediate assembly code.
Also debug code at the assembly instruction level to see where you are going wrong.

[Anonymous No.1595660]

Best place to get some cheap simple single layer PCBs printed?

[Anonymous No.1595662]

>>1595205
What kind of slaves are they? Why do they need 5 and not 3.3?

[Anonymous No.1595665]

>>1595647
>study the intermediate assembly code
don't do this. compilers are either troglodyte or galaxy-brain depending on optimization level

>>1595660
they're all pretty much the same
>single-sided
you mean, 2-layer with one layer blank. proto houses don't bother with a separate flow for 1-layer boards. may as well use the second side, it's free to you

[Anonymous No.1595675]

If you apply some power to a transistor base, the transistor amplifies it.
So for example, let's say that the transistor is 100x, so if you put 1ma at the base it pumps out 101ma as a result

But what happens if the power source is capable delivering only 50ma? does that mean there will be 51ma going out of the transistor?
what if the power source can supply 100A, will the current flowing from the tranny be still only 101ma?

[Anonymous No.1595682]

I've been asked to calculate the closed-loop input resistance and the closed-loop output resistance using multisim.

The internet hasn't been helpful and my tutor has no idea, so any help would be greatly appreciated.

[Anonymous No.1595693]

>>1595665
single layer boards are almost always cheaper...wtf are you on about?

[Anonymous No.1595737]

Why can't you use only one resistor on the cathode, instead of 3 on all legs?

[Anonymous No.1595747]

>>1595737
Why can't you do it to see what happens?

[Anonymous No.1595748]

>>1595747
I only have one. Stop being toxic.

[Anonymous No.1595749]

>>1595737
what's the difference to the common cathode when one switch is closed versus all three switches closed at the same time?

[Anonymous No.1595751]

>>1595737
>Why can't you use only one resistor

>>1595749
current through a resistor - voltage is dropped across the resistor

measure voltage at cathode with all switches open
measure voltage at cathode with one switch closed
measure voltage at cathode with two switches closed
measure voltage at cathode with all switches closed
get the answer to your question

[Anonymous No.1595756]

>>1595632
>Even when I have logically sound code it doesn't work just because

post a simple real-world example. and "simple" means less than 50 lines, preferably about 10 max. If I had to guess, you come from a higher level programming background and don't really get what assembly code does. Assembly can be tedious, but once you get used to it, it has an elegant simplicity (at least on 8 bit devices) that appeals to me.

[Anonymous No.1595757]

>>1595756
If i post my code, what prevents you from stealing it?

[Anonymous No.1595762]

>>1595757
Who's gonna steal 50 lines of random assembly code? Is there a super clever algorithm hiding in those 50 lines?

[Anonymous No.1595767]

>>1595757
>If i post my code, what prevents you from stealing it?

heh. The last time I went back to /r/Arduino, land of the tards, and posted a cool little project I had done, some shithead with a billion karma looked at my weird line names and proclaimed it to be reverse-engineered. Like someone steals fucking code to do rgb led crap.

Anyway, you can put it on pastebin with "read-only" in the title and that allows us to read it but we can't down or run it.

[Anonymous No.1595785]

>>1595756
Using 68HC11 instruction set
This is as simple as can be; just make a loop with a WAIT instruction and an interrupt service routine. Setting the IRQ pin low prints the message but ends the program afterwards. It's supposed to print the message repeatedly until the IRQ is set high again. From that it looks like the RTI instruction isn't doing its job.
Tried setting a breakpoint and the monitor decides to act all fucky

[Anonymous No.1595790]

>>1595785

I'm not familiar with that, but which one of those instructions sets the stack pointer, and is it in actual ram you have installed? Often when your first routine does not return it's because the stack pointer is configured properly.

[Anonymous No.1595791]

Is regular black electrical tape OK to block a 3.3v lead?

have a few leads on a sata power cable I need to block but someones telling me I should be careful about heat

[Anonymous No.1595804]

LEDs have been around for quite some time it seems... Why are LED light bulbs just now becoming popular and readily available? Couldn't they have been made a long time ago?

[Anonymous No.1595807]

>>1595790
I wish that was the case, but when I run the program it runs through buffalo monitor which doesn't need to have a stack pointer set since the monitor itself performs that function. But if I ran the program outside of that I would need to set a stack pointer

[Anonymous No.1595812]

>>1595804
efficient bright LEDs with white light aren't that old

[Anonymous No.1595814]

>>1595767
I don't blame him. people steal my code all the time.

For example i saw someone sketch code and he
used there the digitalRead() which is exactly what i use in my code i posted there as well

[Anonymous No.1595816]

>>1595737
you can, but if you only use one color.
you can also use more colors but the brightness will decrease

[Anonymous No.1595825]

>>1595804
they have been around for ever but it hasnt been soo long ago where the efficiency outweighs the cost of the leds. plus the technology got better

[Anonymous No.1595828]

>>1595807
>doesn't need to have a stack pointer set since the monitor itself performs that function.

Sorry if you already know all this, but:

The stack is a block of ram that the stack pointer points to. If the stack pointer is not initialized to point to real ram then it will screw up.

From the buffalo doc: "Two extra bytes are placed onto the stack before the return from interrupt (RTI) is issued so that the first unmatched return from subroutine (RTS) encountered will return control back to the monitor program. "

so yeah, the monitor manipulates the stack pointer but leaves it up to you to handle the stack.

In addition, the buffalo monitor uses a lot of the on-chip sram, so you probably should place the stack in external ram: "the BUFFALO uses the MCU on chip RAM locations $0036 $00FF leaving only 54 bytes for the user."

[Anonymous No.1595831]

>>1595665
>compilers are either troglodyte or galaxy-brain depending on optimization level
Compilers aren't really galaxy brain. Avr-gcc for example is a buggy piece of shit that produces buggy object code at high optimization levels.
Compiling a 3 line snippet so this guy can understand what he's doing wrong is going to be better than what he has now which is nothing.

[Anonymous No.1595834]

>>1595828
>This will initialize the stack pointer which is necessary when running outside of buffalo but should not be done while running under buffalo since it must handle the stack; cause the program to NOT try to "return" at the end and lastly, program the HC11 reset vector to go to the beginning of the program (the label START) when powered on. Re-Assemble HELLO.ASM as described in the "Assembling Source Code" section.
http://www.aspisys.com/code/hc11/buf34.html

[Anonymous No.1595841]

>>1595834

thank you sir. I deleted the mis-info.

[Anonymous No.1595869]

>>1595748
>I only have one. Stop being toxic.
You're a liar or an asshole, gtfo.

[Anonymous No.1595889]

>>1595675
I think you're on the right track but lacking technically in the fundamentals.
In short: there are 4 modes of operation for a transistor, besides off and reverse there's active (amplifier) and saturation (ON switch). What you're describing is Sat (essentially). First problem is BJTs operate as current amplifiers, but only with proper biasing via resistors or active loads. So, secondly your assumptions are basically correct. The transistor will probably enter saturation when you hit .5 mA, and anything above will be wasted. and yah on second.

A simulator like this will let you know if you're on the right track

https://www.falstad.com/circuit/

[Anonymous No.1595891]

>>1595682
sorry bud this is your assignment
BUT
a hint might be that R = V/I. so input resistance = (input voltage)/(input current).
Actually that's not a hint it's literally the answer I would imagine. enjoy

[Anonymous No.1595907]

>>1595889
thanks, i basically want to operate them like fets

[Anonymous No.1595916]

>>1595693
not in proto quantities. show quote or tits

>>1595831
galaxy-brain in the meme sense of something incomprehensible but still stupid

[Anonymous No.1595991]

what's the best way to make a 4-channels 5V PWM to 0-10V analog converter?
I made this with a op-amp but i'm pretty sure it's wrong

[Anonymous No.1595998]

>>1595991
draw your schematics more functionally pls

[Anonymous No.1596028]

>>1595998
Yes, and if it must be failstad, click greyscale click invert to get rid of the crayon colored blackhole style.

[Anonymous No.1596030]

>>1596028
looks like this

[Anonymous No.1596035]

>>1595991
What's with the R2 R2 and R5 R1 and what above the resistors?
As far as the circuit goes, perhaps look into delta sigma DACs. Otherwise it looks like it will work to some extent, though for these sorts of things you do want a frequency of a MHz or more for audio DAC uses. Some feedback to the ADCs in the MCU might add consistency.

[Anonymous No.1596042]

>>1596035
I didn't edit the labels properly
it's for a 20 years old 230V dimmer that use DC 0-10V as remote input, so it's a very basic appliance .

[Anonymous No.1596044]

>>1596035
>I don't know what I'm talking about but let me paste a bunch of keywords that I don't understand so I can sound smart
stop posting forever

[Anonymous No.1596075]

>>1596042
Well with the level of accuracy you'd need anything will do. Give that circuit a try, but chances are you might not even need those buffers. But I think your PWM would need to vary from 0V to 10V for that to work properly (not likely), so I'd instead increase the gain of your buffers from 1 to 2 or higher, with respect to a properly chosen ground.

>>1596044
>a bunch of keywords that I don't understand
Instead of modulating the duty cycle proportional to the output voltage you want, you modulate it proportional to the change (delta) in output you want, and use a circuit that adds (sigma) this potential to the previous output, roughly speaking. It makes for a more linear DAC, among other improvements. It's a circuit that wouldn't be too much of a departure from the original one (just using integrators instead of low-pass filters and buffers and changing how the PWM signal was generated on the software end) and could provide a notable increase in performance for precision purposes. But if you think this suggestion was erroneous, perhaps instead you could provide your own two cents?

[Anonymous No.1596094]

>>1596075
I did. the only problem with his original circuit was not knowing how to use an opamp for gain in non-inverting mode
>>1595998
there are already too many nonlinearities in the path from PWM to light intensity to justify the complexity and the frequency limitations that bit-banging a d-s output would add, when simple interpolation between a few points will correct adequately in either case

[Anonymous No.1596096]

>>1596075
Thanks
My main worry was about the voltage, since I'm using an arduino as the PWM input (so 5V).
VCC is likely to be 12V since that's what I have under the hand.

[Anonymous No.1596097]

>>1596030
oh like this?

[Anonymous No.1596099]

>>1596096
yeah just add some gain to your non-inverting amp, like
>>1596030
gain = 1+(Raround/Rground) with respect to ground

[Anonymous No.1596144]

>>1596094
>>1596096
Actually, adding gain to the op-amp might not be as good as just throwing transistors on each PWM lead before the filters. First converting the 0V-5V PWM to 0V-12V (inverted) and feeding it into an op-amp buffer that can go down to 0V output means less passives for the setting of the gain. But since your amp's ground rail will just be 0V anyway it shouldn't make too much difference; it's basically 2 extra passives per PWM channel either way. I just think it will be a bit more consistent to use transistors, plus the PCB layout will likely be easier. 1 extra passive per PWM channel if you're a shitlord who doesn't put resistors in series with FET gates.

[Anonymous No.1596145]

>>1596144
stop babbling and start drawing

[Anonymous No.1596147]

>>1596145
this

[Anonymous No.1596157]

>>1596147
y tho
>another transistor
>pulls toward 100% power until micro comes out of reset and configures ports, could be signficant depending on RC filter time constant
>less headroom due to non-RR-input jellybean op amps
as for
>layout easier
I don't see that there would be any significant difference

[Anonymous No.1596168]

>>1596157
Oh if you're doing SMT then yeah the layout wouldn't me much of a problem. The rest of the issues I hadn't really considered.

[Anonymous No.1596171]

Can anyone tell me if the grey caps in here are electrolytic or paper caps or not? It's from an old Japanese made signal generator, and I don't know anything about these capacitors and want to know if I need to replace them or not.

[Anonymous No.1596173]

>>1596168
that's THT with vertical components. was just too lazy to draw the drill holes in

>>1596171
/ohm/ RULE 2

[Anonymous No.1596179]

>>1596171
>>1596173
Here is a better picture. All the caps in question are the grey ones under 1uf in value.

[Anonymous No.1596194]

>>1596179
If they have no polarity markings (like the + on those black capacitors) they're likely not electrolytic capacitors, polymer film capacitors sounds more likely, but they could conceivably be bipolar electrolytics.
If they're that old you can compare them to ones on https://tubes-store.com/, which has paper-in-oil, various polymer film, etc. You can also calculate their maximum energy per volume (E = 0.5*c*V^2) (V = L*π*R^2) and compare them to known values for capacitor technologies, but that method isn't terribly advisable. A quick comparison of the black polarised capacitors' capacitance with respect to the white/grey caps should show that the white caps have significantly lower capacitance at similar dimensions and voltages, which should be expected as electrolytics have a significantly higher energy per volume.
If you're planning on replacing capacitors, low-ESR 1% (or less) ones should do the thing justice.

Those variable capacitor plate banks look cool as shit.

[Anonymous No.1596196]

>>1596194
>low-ESR 1% (or less) ones should do the thing justice.
ceramic caps of significant size have a voltage dependent capacitance. better replace them with polyester, which will generally have a lower ESR than paper, especially if axial-leaded, but check the datasheet as always

[Anonymous No.1596204]

This is how you turn $2.5 bulb into $30 equivalent e-bike light.
But how can I focus it?

[Anonymous No.1596207]

>>1596204
optics ≠ electronics
glhf

[Anonymous No.1596212]

>>1596207
Light is an electromagnetic wave.
Electromagnetic waves are electronics.

[Anonymous No.1596214]

>>1596212
we deal with wires here. try >>>/sci/

[Anonymous No.1596215]

>>1596214
Where can I get wire, but for light?

[Anonymous No.1596231]

>>1596215

[Anonymous No.1596253]

>>1596212
I think Faraday or Gauss one of those guys managed to do that with some wacky glass of some sort, but for the most part the best you can do with electrostatics is changing the index of refraction of a material slightly. Not enough for a variable lens, but enough to turn a waveplate on or off.
I'd buy or make a parabolic reflector, though it would be pretty large considering the outside radius of all the LED chips combined. Having 6 (4?) reflectors instead, one for each active LED might be space efficient enough to attempt. Lenses in comparison would be a pain to mount, and harder to customise, even more-so for optical fibres.
Also that glue better be good at high temperatures.

[Anonymous No.1596281]

>>1596028
>failstad
as opposed to what? that overcomplicated piece of shit lt spice? no thanks

[Anonymous No.1596302]

>>1596281
>overcomplicated
I find it quicker to use, though it's certainly missing some parts/has parts that require some sort of manual definition, which I can never be bothered to do. If it's just a layout you want to show, then ltspice or kicad will make it look nice at the very least.

[Anonymous No.1596332]

>>1596281
circuitlab has a clean diagram output

[Anonymous No.1596335]

>>1596332
>current year
>not using FETs for very high impedance sensing

[Anonymous No.1596336]

>>1595682
I know how to calculate that but not how to multisim it other than doing a virtual experiment.

[Anonymous No.1596340]

>>1596335
>current year
still missing the point

[Anonymous No.1596342]

>>1596332
>three BJTs
Is that a super-Darlington?

[Anonymous No.1596463]

>>1596342
it's a Trarlington

[Anonymous No.1596524]

>>1596342
>>1596463
I always wondered - why is it even called by Darlingtons name? It's such a straightforward thing to do, as if you called 1+1=2 equation by someones name. Similarly Sziklai pair which is also pretty obvious. Does it have some special non-obvious properties that I'm not aware of?

[Anonymous No.1596529]

>>1596524
sure, it's obvious in hindsight, but Darlington invented his eponymous circuit maybe 10 years after the transistor was invented
nobody has come up with a more common short name like "cascode" or "long-tailed pair" so why not name it after its inventor?

[Anonymous No.1596538]

Why do conical tips even exist? They are cancer...

[Anonymous No.1596552]

Do I understand correctly that trying to figure out an LEDs voltage/current for a given resistor in a simple resistor-LED circuit is actually really complex?

[Anonymous No.1596565]

>>1596552
by complex you mean determining the LED device current-voltage relationship equation, or that you don't know the practical trick with treating an forward biased LED as a voltage source in reverse?

[Anonymous No.1596566]

>>1596538
dunno, I avoid them too

[Anonymous No.1596574]

>>1596538
It builds characters and weeds out the weak.

Anybody who recommends tips that aren't awful to a noob is contributing to the dumbing down of the industry.

[Anonymous No.1596581]

>>1596574
>>1596566
Why all soldering iron manufacturers put it as default tip? It is annoying,

[Anonymous No.1596585]

>>1596574
BIN
THAT
KNIFE TIP

[Anonymous No.1596592]

>>1596585
Knife tip is awesome.
>Massive through hole
No problem. Sure, proper conical tip with cut end exists, but it is only good for through hole and QFPs.
>SMD (Surface mount devices)
No problem. Wide blade allows to heat 4-6 pins at once and lift them ever so slightly from board.
Same goes for soldering
>SMD (Super miniature devices)
No problem, knife has a fine tip.
>Solder blob removal
Super easy.
>Fucked up pad?
No problem, do scrapy-scrapy and solder a jumper wire

[Anonymous No.1596603]

>>1596581
because then you have to buy another tip

[Anonymous No.1596627]

>>1596581
They don't, plenty of T12-based irons/stations come with the K chisel tip.

[Anonymous No.1596637]

>>1596627
Based Chinks.

Anyway, can someone redpill me on wire types, and which I should use?
Are solid-core wires under 0.25 mm2 OK for vibration?

[Anonymous No.1596728]

how do you get past calc II when your professor, a mathematics doc, sees herself as the Gatekeeper of Engineers

[Anonymous No.1596732]

>>1596603
or two or three or four, or if you're rocking a 900 series compatible, buy the three assortments by B,C,D types and the misc tip assortment for $3 each

>>1596637
you should really just support your wire such that it doesn't vibrate e.g. hot snot it down

>>1596728
oral sex

[Anonymous No.1596740]

>>1596732
>you should really just support your wire such that it doesn't vibrate e.g. hot snot it down
But how bad is it?
It is an electric scooter, so it experiences a lot of vibration. Since it is not an airplane, I'm not really worried about wire snapping, but I don't want it to happen obv.
I hot snoted wire on ECU PCB, but other end (and entire length) can't be fixed to anything. So it will vibrate.

[Anonymous No.1596742]

>>1596281
pspice or bust faggot.

And maybe Matlab for some control systems and signal processing applications too.

Buy it or pirate it, doesn't matter how you get it but it's fucking 2019, you have options.

[Anonymous No.1596807]

Tell me friends, what a poorfag to do when he only has a pile of perboards and a soldering iron to work with, while half of the components he needs come in Shaking My Dick form only?

[Anonymous No.1596809]

>>1596740
in which case stranded wire, the more strands the better

>>1596807
dead bug style

[Anonymous No.1596810]

>>1596809
>dead bug style
that is very hard to do, you need a microscope and it takes hours to make a circuit which you make in 5mins with smds
I really don't want to get into all that printing circuit schematic on a4, then splooging it on a copper board and melting it in acid, it's all just so.. tiresome.

[Anonymous No.1596812]

>>1596810
Fuck, this looks really good though,
https://www.youtube.com/watch?v=sNh0ubRcTYU
And i do have a 3d printer

[Anonymous No.1596815]

>>1596807
get cheap adapter pcbs

[Anonymous No.1596816]

>>1596807
Get a job.

[Anonymous No.1596819]

>>1596816
>get about 50 good years on this shitty rock where you are in a decent enogh physical form to enjoy life
>just 50 out of trillions of years that the universe have been around
>waste a third of them on doing a thing you hate every day, only to be rewarded with small paper rectangles with made up value for all your sweat and blood and most importantly, your most valuable highly limited resource, time, by your jewish masters
my pity for you blind sheep knows no bounds

[Anonymous No.1596821]

>>1596819
Get a good job then you worthless bottom feeder.

[Anonymous No.1596822]

>>1596812
but by this time you may as well drop a Dremel tool in there and skip the etch step entirely

[Anonymous No.1596824]

>>1596822
If the SMD parts aren't ridiculously small you can also just cut the contacts of the perfboard in half with an X-acto knife.

[Anonymous No.1596827]

>>1596812
I don't find permanent marker survives the etch process very well, at least not with my persulfate etchant.

>>1596819
Since the alternative is either to starve to death or happen to live in a foolish enough country to support your living expenses for nothing in return, I'd pity you either way.

[Anonymous No.1596829]

>>1596827
My plan was to attach a small motor with a one of those small diamond milling bits to the 3d printer nozzle and then it will be one stop shop for pcbs, no nasty acid business

[Anonymous No.1596831]

>>1596829
Isn't that basically turning a 3D printer into a CNC router? Go for it, there are probably conversion guides online, but you'll need to ensure that your board is perfectly level (to within less than the copper thickness), which might take some work. You'll want a V-bit, and HSS or even carbide will likely be better than diamond. Diamond is usually more of an abrasive than a cutter so it would take longer to make a pass, but if it's designed for milling it might be fine. I'd do drilling beforehand, and purchase some of those THT rivets for any thru-holes in 2-sided boards. I've ordered some of those myself but they haven't arrived yet.

If you're wondering what sort of motor to go for, there are cheap multitool-style motors without any handle/housing that might be easy to mount, and they already have some sort of collet chuck on the end. Though I'd advise replacing these collets with a keyless chuck, since they can and will be off-centre.

[Anonymous No.1596832]

>>1596829
>no nasty acid business
use tap water
https://www.youtube.com/watch?v=nGL8X8FS4eQ

[Anonymous No.1596834]

>>1596832
>use tap water
same thing xd lmao

[Anonymous No.1596836]

>>1596831
>board is perfectly level
Well you need perfectly level bed for 3d mprinting anyway so it's not like that is a problem, my printer even has automatic leveling
i already have a motor and the milling bits in my diy box, they have been there for months now since i am super lazy to do anything with them. i want to try the ball shaped diamond bits since i have set of 10 already with various sizes, also i don't see why cutting too deep into the board would be a problem, as long as you remove the copper where you want if you go deeper than that isn't a problem
i just have to design some mount that can hold the motor on the extruder well enough to take the milling pressure

[Anonymous No.1596838]

>>1596836
>my printer even has automatic leveling
Double bonus. I assumed PCB milling requires higher tolerance than 3D printing, but perhaps I was mistaken.

[Anonymous No.1596840]

>>1596829
Letting a mill throw copper dust in the air is a million times nastier than ferric chloride.
Don't mill pcbs without a dust collector and mask.

[Anonymous No.1596841]

>>1596840
he can just put a magnet next to the mill to collect the copper dust

[Anonymous No.1596844]

>>1596841
Are you joking?

[Anonymous No.1596845]

>>1596841
fiberglass dust is also nasty shit that you do not want to breathe

[Anonymous No.1596847]

>>1596845
you need to breathe in small amounts of it at first to build up your tolerance

[Anonymous No.1596867]

So I've been entertaining the idea of making noise on the wi-fi/bluetooth band to try and disable portable speakers. I never messed with anything above 100Mhz, so the idea of even trying microwave frequencies is kinda distant to me.
Is it feasible to work with 2.4Ghz using copper clad ?(in what people call manhattan building style or point-to-point).

[Anonymous No.1596872]

>>1596867
Or if I can get off my lazy ass and learn stuff about network protocols maybe there is a way to modify a wifi/bluetooth device to disrupt the channel. But heh, it's just an idea so far.

[Anonymous No.1596884]

>>1596872
Modifying an existing BT or WiFi module is probably more feasible. An ESP8266 might be able to do it, google "ESP8266 wifi jammer" and see what you get. Note that WiFi is on both 2.4GHz and 5GHz bands, so you may want to be able to jam both, though 2.4GHz would be fine for older routers/devices

[Anonymous No.1596886]

>>1596832
FeCl3 is paramagnetic, not ferromagnetic, so the magnet will not do much. It's still a good experiment.

[Anonymous No.1596892]

>>1596847
yes, the next thing he'll know is him breathing whole pcbs at once
that's not funny, happened to a college of mine

[Anonymous No.1596895]

>>1596892
I once inspected a tiny smd resistor on my finger and accidentally breathed it in.
I really hope it was tinned with lead free solder-

[Anonymous No.1596900]

what's the feasibility of rigging something together from one of these small harbor freight batteries
>https://m.harborfreight.com/automotive-motorcycle/battery/12-volt-10-ah-sealed-lead-acid-battery-62586.html
to use as a portable power source, such as for charging a laptop?

[Anonymous No.1596903]

>>1596900
Lead batteries aren't a great portable power source since they're pretty heavy for their stored energy.

Also most laptops need more than 12V so you'd need a boost converter.

[Anonymous No.1596905]

>>1596903
I figured it would be pretty difficult and dangerous to just hook up a Motorsport battery directly to my laptop, I was thinking of getting a small 120v AC inverter, that way the laptop's own charger can deal with it

[Anonymous No.1596908]

>>1596905
That's pretty inefficient. You can get small cheap boost converters from Ali/ebay. Just check if they can handle enough current.
You can also add an PTC inline for additional protection.

[Anonymous No.1596910]

>>1596908
I have plenty of boost (and buck) converters ready to go, I just can't power most of the stuff I want to power directly from DC current

https://www.amazon.com/BESTEK-300W-Power-Inverter-Adapter/dp/B004MDXS0U/
so snipping off the cigarette adapter, then attaching it (maybe with ring/spade terminals) to the battery would be a pretty poor choice?

Are there other large capacity batteries that are lighter than lead batteries? 18650s are pretty cost prohibitive

[Anonymous No.1596913]

>>1596910
A good cheap source of 18650s are laptops.
Plenty of people throw away old/broken laptops even when the battery is still good.

If you carefully pry the laptop battery open you can salvage the 18650 cells from it.

[Anonymous No.1596917]

>>1596913
But then I have to worry about mixing/matching cells of different ages and cycle counts, overcharging, overdischarging, short circuit protection, load balancing, charging circuitry, and in the end I'd still need an inverter anyway

[Anonymous No.1596960]

Does a regular black sharpie work well with fecl3?

[Anonymous No.1596992]

>>1596917
Again, ali/amazon has cheap charger boards for all sorts of currents. As sad as it may be, comms stuff, small power converters and complex logic stuff aren't good options to diy from the ground up.
>>1596960
I got mixed results. I just gave up on etching and just scratch the copper with a sharp blade. Until I stop being a broke college student in a small apartment without CNC capabilities that is.

[Anonymous No.1597000]

>>1596960
>>1596992
Why fuck around with a sharpie?
All you need is a laser printer, an old clothing iron, and pages ripped from a catalogue or magazine.

It's possible to get all that for free or at least for very little money.
Offices are constantly throwing out their old perfectly fine laser printers, you can get them cheap on ebay or even for free with a bit of luck.

[Anonymous No.1597011]

How do I decode the codes on foil & ceramic caps? I generally check them with a multimeter & sort them by that, but I also want to be able to know the voltages & tolerances of them too. Like for example, I have some of those little green film caps marked with 2j272j, how would I make sense of this marking? I know that these capacitors are 0.0027uf through measuring them with my multimeter, & so I'm going to assume based off of what I know about other codes that the 27 is 27 & the other 2 is the amount of zeros after it so it is 2700pf, but what is up with the 2j & the j at the end?

[Anonymous No.1597034]

>>1597000
>and pages ripped from a catalogue or magazine
why?

[Anonymous No.1597038]

>>1597034
Free transfer paper.
You want very smooth paper for that.
Normal printing paper won't work.

But you might have to put it on thicker paper - some printers will eat paper that's too thin.

[Anonymous No.1597043]

>>1597038
But magazine papers are already printed on, i don't understand how you are supposed to print your schema on them. It will be mixed with the text and stuff

[Anonymous No.1597046]

>>1597043
It doesn't matter. That stuff won't get transferred onto the PCB, only the toner will.

[Anonymous No.1597054]

>>1596565
What I mean is what happens exactly when I run an LED in a circuit with different resistance than what the single voltage/current spec of the LED suggests (for example dimming with higher resistance)

[Anonymous No.1597057]

>>1596565
>the practical trick with treating an forward biased LED as a voltage source in reverse?

maybe that works for you, and I see the logic, but to me that's a horrible concept to suggest to anyone learning about electronics. Either assume the diode has the nominal voltage drop as a rough estimate, or use the V-I curve if you really need to, but to think of it as a SOURCE seems wrong-headed, since it is not a source in any way.

Please explain what I'm missing, and how this "trick" is practical.

[Anonymous No.1597058]

>>1596552
>is actually really complex?

Yes, especially since the voltage-current characteristic that is published is just a representative value and is not exact. The real question is, why are you concerned about this? Design your circuit so that the LED is always bright enough to do whatever it is supposed to do, and avoid excessive current, and this does not have to be complex unless your source voltage is terribly unregulated. If you have a regulated voltage source then pick a resistor that gives you a safe LED current and forget about it.

[Anonymous No.1597070]

>>1597054
Diode IV relationship is exponential and also depends on temperature. Because of those two reasons, accurately calculating current of a series LED-resistor is more complicated than just using (Vsupply - Vforward) / resistance = current.
So yes calculating it accurately is more difficult but there's damn near no point because you're not going to be compensating for temperature anyway.

[Anonymous No.1597071]

>>1597046
So i take a copper pcb, a page from a magazine, stuff it into a laser printer, i have one so that is nice, and then put it on the pcb and iron it? that is it? the give it a nice little fecl3 bath and i have a finished pcb?

[Anonymous No.1597075]

>>1597011
Feb 2017 2700pf ±5%
you can find that, you really can

[Anonymous No.1597099]

>>1597071
Basically. You also need to wash and polish the copper plate, carefully wash off the paper before etching, and wash off the toner after the etching using acetone.

It also requires a bit of experimenting for good results.
There's a ton of resources out there for pcb toner transfer.

[Anonymous No.1597142]

>>1597057

[Anonymous No.1597157]

>>1597099
The laser printer outputs a super thin layer of plastic so i assume the transfer from the paper to the pcb will rarely be perfect.
Maybe i could 3d print actual plastic onto the pcb. That way it would be like 0.2mm thick and perfectly placed, no holes anywhere. And super easy to peel of later, no acetone needed.

[Anonymous No.1597187]

>>1597157
It's thick enough, especially if you set it to maximum saturation.

pic related is the third pcb I ever etched
There's a big error there but it was a pretty janky copper plate to begin with, which I also didn't properly prepare. Still got the details of that 2cm tall animu image pretty well.

[Anonymous No.1597215]

>>1597187
OR you could buy a PCB with photosensitive material (bungard).

1. Print your stuff with on a transparent film, shit's available everywhere
2. Take the top black layer off the PCB, put your fill on top of that, with the printed side on the bottom.
3. A piece of plastic on top so remove shadows
4. Put a UV light source over it for like 10 minutes
5. Make a very soft sodium hydroxide solution (half of tea spoon per liter) with worm woter
6. Shake it there for a while. Whoa, the exposed parts go away.
7. Take the PCB out, then do the etching like you normally do (I do it with ferric chloride but that shit is nasty)

You can achieve 0.2mm with this. With a laminating machine you get a reliable results by a magnitude.

[Anonymous No.1597226]

So if I connect a USB wire directly to an 18650 battery, as long as I limit the current to below 1A, and limit the voltage at around 4V, and unplug it it when the battery is charged, it should be fine, right?

That's what I understand from the manual at least.

[Baird !supERrmOTo No.1597246]

If I have two 12v batteries with their positive poles connected by a Voltage Sensing Relay, I can literally just put a switch in parallel with the VSR and close it as a manual override, right?
Will the VSR cause any issues under load?

How much reserve capacity would I need in a battery to run the following for 8-12 hours? I'm looking at a single 125ah deep cycle right now.
How powerful of an inverter would I need? Seems like 500w would be more than enough.
>laptop
>cell phone
>LED light strip
>small fan

Pic related

[Baird !supERrmOTo No.1597249]

>>1597246
I think this is what I mean.

[Anonymous No.1597271]

do I need to spot-weld 18650s? What's stopping me from using adhesive copper tape?

[Anonymous No.1597277]

>>1596917
>>1597271
just had an idea with my portable laptop charger/power bank

the *laptop* doesn't need AC current, only the AC converter needs AC current. The AC adapter is removable, and the rest of the cable would theoretically run right into the laptop with DC current

meaning all I need to do is make my battery pack as normal, then have the output be pic related (if I can figure out the name), and as long as I get the circuitry right it ought to work just fine

[Anonymous No.1597278]

>>1597277
just kidding I got the order fucked up, the connector in the comes FROM mains, TO the ac adapter. I would have to modify the cable after all, which sounds sketchy.

[Anonymous No.1597287]

>>1597246

I'm about to do the same thing as you. If that's all the stuff you will be using then ditch the inverter and get a 12v laptop charger and a 12v or usb powered fan.

Going all 12v is much more efficient. Get a small inverter as a just in case if you really think you need it.

[Anonymous No.1597290]

>>1597246
>>1597287

Forgot to add...

125ah of battery is actually overkill. I'm going to run a 12v fridge, laptop, fan, and led light off a 105ah battery that's hooked to 200w of solar and the alternator through a ctek d250sa. By my calculation i'll only use 40ah in a 24hr period.

[Anonymous No.1597294]

>>1596895
F

>>1597011
630VDC
http://kaizerpowerelectronics.dk/theory/capacitor-code-table/

>>1597271
possibly, the resistance of the adhesive

[Baird !supERrmOTo No.1597297]

>>1597287
>If that's all the stuff you will be using then ditch the inverter and get a 12v laptop charger
Interesting, I'll look into this.

>125ah of battery is actually overkill
Using all of the stuff I mentioned at full chooch is about 265w.
Lets say worst case scenario, I use everything at full load for 8 hours, that's 2120wh.
The battery is 12v. I plugged all that into some online calculator and it told me I would use 176ah.

Is this correct?

[Anonymous No.1597308]

>>1597215
Ensure that you're using an appropriate transparency, one that absorbs plenty of ink. I believe the ones intended for screen-printing are good for this, I bought some of the non-waterproof ones that are covered in an ink-absorbing gel, but you can also get ones that are waterproof, and you can get them in either inket or laser varieties.

[Anonymous No.1597314]

>>1596819
we're not the ones asking for help, friend

[Anonymous No.1597316]

>>1597271
can't comment on vice-versa but have you consider just soldering?

[Anonymous No.1597319]

>>1597308
absorption is not desirable for photo transfer, you want the pattern directly on the photosensitive surface to prevent light from creeping around the edges

>>1597316
shiggy

[Anonymous No.1597324]

>>1597319
>absorption is not desirable for photo transfer
Yes it is, otherwise screen-printers wouldn't use it. It doesn't leech into surrounding areas, but it ensures that you get a thick and highly opaque layer of ink, since most of that ink will just run off a normal sheet of acetate. Talking about inkjets that is.

[Anonymous No.1597330]

>>1597297
>265w.
will need ~25A from the 12 volt battery
>>1597297
>8 hours
25 x 8 = 200Ah
>>1597297
>176ah.
don't forget to include the efficiency factor of the inverter

[Anonymous No.1597331]

>>1597297

>176ah

That's correct. You must have a beast of a laptop though.

[Anonymous No.1597337]

>>1597319
>shiggy
I mean the guy didn't specify how many, the requirements, etc. What evidence is there against it (srsly)

[Anonymous No.1597338]

>>1597337
the ones that spewed electrolyte all over my hand and room

[Anonymous No.1597344]

>>1597338
Lol, if it was Chi-Ion I wouldn't doubt. I had one straight up rocket from a metal vape mech mod.

But based on samsung datasheet (last pg), they give it A ok rating for temps above 120 C. It shouldn't get over 100 if you have a hakko or eq

https://www.powerstream.com/p/INR18650-25R-datasheet.pdf

[Anonymous No.1597411]

>>1597226
You will die in a horrible fire.

[Anonymous No.1597412]

>>1597215
uv plates cost several times more than the normal ones here
i am really tempted to try the milling with my 3d printer since i don't have to handle nasty acid that way, but i don't know

[Anonymous No.1597415]

>>1597344
>120°C
then you're not making a properly soldered joint

>>1597412
there's been much experimentation and plenty of documentation on low-end application of dry-film photoresist. DF is pretty cheap and can be reapplied in case of error

[Anonymous No.1597417]

>>1597415
>>1597412
chinks offer 10pcbs for $2, free shipping
are you literally retarded to even consider making them at home?

[Anonymous No.1597432]

I need to take 3V - 5V and turn it into 3V - 3.3V
What would be the best way here? things like lm317 won't really work since they can't really take 3V and output 3V

[Anonymous No.1597435]

>>1597417
some people have short attention spans. besides, it's cool and useful to be able to bang things together on command

>>1597432
how much current?

[Anonymous No.1597439]

>>1597435
5ma - 200ma (short wifi burts)

[Anonymous No.1597452]

>>1597432
LDO regulator is probably the way to go, but a up/down capacitive/charge pump converter might be better.

[Anonymous No.1597455]

>>1597417
Do you think that any more than 20% of circuits built by anons on this general serve any practical use? Just like designing and testing circuits, designing and testing circuit boards is something that can be fun and rewarding to mess about with as a hobbyist. Regardless of whether there are better ways to spend your money.

[Anonymous No.1597461]

>>1597455
i wish there was a better way than fecl3 to remove the copper though, i always feel low key scared when pouring it down the drain praying that all the pipes in the house are plastic

[Anonymous No.1597464]

>>1597461
I use persulfate, I think it's worse, but at least I can see through it. I never pour it away, I just have a jar full of waste material that I occasionally leave outside to evaporate off the water and hope no bugs get in.
Ferric sulphate might be a reversible etchant via electrolysis, I'm pretty sure aqueous iodine might work too, provided pH is correct.

[Anonymous No.1597466]

>>1597439
there are regulators with dropout voltages as low as 120mV on a 500mA load. enjoy the DFN
https://www.st.com/content/st_com/en/products/power-management/linear-voltage-regulators/low-dropout-ldo-linear-regulators/ultra-low-dropout-ldo-regulators/ld56050.html

>>1597461
CuCl process works fine for me when I need to etch. add 1 volume muriatic acid to 2 volumes (3% H2O2). sparge with air or add H2O2 to regenerate

[Anonymous No.1597468]

>>1597466
I don't suppose they make one as tht? i can't solder this microscopic smd crap ;_;

[Anonymous No.1597469]

>>1597415
>properly soldered joint
The internal temp (120), not the surface temp. eg ICs

[Anonymous No.1597475]

>>1597468
Then learn some, or apply yourself.

[Anonymous No.1597478]

>>1597439
>short wifi burts
How short, 8 seconds again?
https://www.aliexpress.com/item/10x/32804195329.html
Select closest pair or triple, run in parallel.

[Anonymous No.1597483]

>>1597478
Nice advice, faggot. That switching regulator mostly introduce ripple, effectively fucking up the radio communication. He needs a linear LDO.

>>1597432
I see you're doing lipo? How about you forget about 3.0V and use only 4.2-3.3v range of the battery with a simple very low dropout LDO like >>1597466

Look up the discharge rate and notice that battery gets below 3.3 after you spent 90-95% of charge.

[Anonymous No.1597489]

>>1597483
>I see you're doing lipo?
3x alkaline D cell in series
It will run arduinos directly without regulation, and then also another ic which works between 2.8V and 3.5V so i think the ldo will be the best option, too bad stores here nor chinks sell any thts i found viable in data sheets so far

[Anonymous No.1597491]

>>1597489
Learn2smd

[Anonymous No.1597497]

>>1597489
>3x alkaline D cell in series
jesus why
also just get a shitty SMT breakout board

[Anonymous No.1597499]

>>1597497
>why
Unparalleled capacity at low price

[Anonymous No.1597501]

>>1597483
>ripple
20mVpp (1.2Mhz) at 100mA, easily removed.

[Anonymous No.1597502]

>>1597499
Well since size obviously doesn't matter, why not use 4 cells in series and a normal linear regulator?

[Anonymous No.1597503]

Why is this Op amp slowly increasing its Vaverage to 0? is there a term for this so that i can research it further?
Its a basic 3 terminal amp with no feedback and an input frequency of 1Mhz and unit gain frequency of one 1Mhz

[Anonymous No.1597504]

>>1597503
image of the circuit

[Anonymous No.1597506]

>>1597503
>>1597504
It's just reaching a zero average as if it were capacitively coupled. Sure something odd isn't going on with your voltage source's reference point? It could also be the frequency response of the op-amp at work. Either way I'd amp up that amplifier's gain and try out your circuit with negative feedback instead, specifically in a buffer orientation (pic related). The whole advantage of an op-amp is its unreasonably high gain that you sacrifice for the sake of improved linearity and a better response at higher frequencies. Its unreasonably high input impedance is also of value to you.

[Anonymous No.1597515]

>>1595804
Bright, efficient blue/white LEDs are relatively new, in fact

[Anonymous No.1597516]

>>1597501
I call it bullshit

[Anonymous No.1597518]

>>1596913
Batteries are usually the first thing to go in laptops, I've found

[Anonymous No.1597521]

>>1597502
Because 4 cells won't allow me to run an arduino directly from them without any regulation. regulators waste powers and the arduinos will run nonstop, the 3v3 IC will not, so regulator there is fine, so all i need to find now is some tht regulator wit something like 200mv drop out at most

[Anonymous No.1597531]

>>1597506
Thanks anon
I've ran it In both multisim 14 and multisim live, and both results are similar. I'd say it'd be the frequency response as it doesn't occur at lower frequencies. I'll test it with feedback later an see how it responds

[Anonymous No.1597539]

odd question... is it possible to build by own custom action cam? I notice sites like ali and gearbest have dozens of variations but many have the same chips and boards. I have a design in mind that im looking for but everything I see is too boxy and big. Is it possible to buy the chips, board and lens and custom make one myself? drone people do this dont they?

[Anonymous No.1597551]

Anyone got any recs for ceramic screwdrivers? Wiha is too expensive for me and I do not want China shit.

Single drivers and sets are both interesting. If not drivers, a non-magnetic (more important than non-conductive) bit set would also be of interest.

[Anonymous No.1597561]

>>1597290
How did you come up with the 40Ah figure? I know that you won't be using everything all the time, but 40 seems a bit low. What kind of fridge are you using? I'd assume its a small portable model considering its 12v, but some of them can easily pull 10A, which can add up quickly.

I'm always interested in alternate power, so I'm just curious about your setup and specific numbers for everything.

And stick with a 12v fan. USB fans are bullshit.

[Anonymous No.1597564]

>>1597521
For your application with normal D cells, pick up a buck/boost regulator and power the whole thing from it. They are efficient and you can find some with very low ripple.
Unless you are going with Li-Ion, the voltage delta over discharge range varies too much to be stable.

[Anonymous No.1597570]

>>1597564
>efficient
converters hover around 80% which is a ton of wasted power when you are counting every mah. I will definitely be running the arduinos directly from the battery since they will be the main consumer.
So i have to deal with the 3v3 somehow. Apart from an ld regulator i could maybe use some simple comparator setup to measure the battery voltage and if it falls under 3.6v as it discharges the power will be fed directly into the 3v3 pin instead of vin, thus bypassing the regulator and removing the 1v drop which the built in one has

[Anonymous No.1597586]

>>1597570
>converters hover around 80%

https://www.maximintegrated.com/en/products/power/switching-regulators/MAX77801.html
>Up to 97% of Peak Efficiency

Vin of 2.3 to 5.5vdc
Vout of 2.6 to 4.1vdc

Given the efficiency can vary, but its 2019, we have switching regulators that can hit 99%.

[Anonymous No.1597595]

>>1597586
That looks nice, but it costs more than I make in 3 hours. I will bookmark it in case i don't find a cheaper solution, since i will need to make 20 copies of my project.

[Anonymous No.1597598]

Is there an easy way to find a replacment for this switch?
It has no markings on it, and the weird shape makes it hard to just use another one.

[Anonymous No.1597602]

>>1597598
looks like a small mouse microswitch like
https://www.aliexpress.com/item/Mouse-button-switch-6-6-7-3-Tact-switch-mouse-microswitch-mouse-button-6x6x7-3-Free/32851392810.html

measure the dimensions and see if it's 6mm x 6mm

[Anonymous No.1597606]

>>1597602
Thanks for the link anon, I guess I was using the wrong search terms

[Anonymous No.1597632]

So i have this schematic. Im trying to control the charge of the capacitor (20mF not uF) and dumping that charge to a load by opening the fets for given amount of times ( 10-100ms). When one fet is open the other fet is closed. For now i put Light-emitting-LED-diodes to debug the thing.

I have 2 problems:
- It seems i can only open the top fet, i cant open the bottom fet. LED1 is on LED2 is off.
- The capacitors will be fully charged if i open the top fet for only 1 ms. I should place a resistor in front of the capacitors to let them charge slower. Do i put it before or after the top fet?

[Anonymous No.1597644]

>>1597632
>open the top fet
Fuzzy language. Better use ON and OFF for both the transistors and the LEDs.
>in front of the capacitors
There's only one, C1, and there is no 'front'.

[Anonymous No.1597648]

>>1597644
fuck off cunt

[Anonymous No.1597657]

>>1597632
T1 = ON -> IPAK1 = ON -> LED1 = ON
T1 = OFF -> IPAK1 = OFF -> LED1 discharges C1 to ≈2V and goes OFF
T2 = ON -> IPAK2 stays OFF because Vgs is now too small, LED2 stays OFF

[Anonymous No.1597741]

>>1597657
LED1 stays on constantly, the cap discharges through the led over 10seconds. The cap is essentially always full when T1 and T2 switches on and off (100ms on times).

Ill poke around to check every connection is okay or not, but it should be fine.

[Anonymous No.1597752]

>>1597657
>>1597741
Replaced the fets, turns out one of them was dead. The thing works fine now. Thanks for your input.

[Anonymous No.1597788]

>>1594926
Broke the fuse...
What can I use instead of it? 16A.

[Anonymous No.1597796]

>>1597788
Look up an AWG chart and find the wire that would give you the appropriate fusing current. The wiki AWG chart is no use, you need a chart that gives you data on copper/iron wires.

[Anonymous No.1597800]

>>1597796
So 28 AWG would work?

[Anonymous No.1597802]

>>1597800
For solid copper yeah.
I hope you have insurance.

[Anonymous No.1597810]

>>1597802
I hope I'd have welding gloves, since Li-ion batteries.

[Anonymous No.1597835]

I was dicking around with using a photointerrupter to source current to an atmega32u4
The photodetector outputs 4ma at 2.4 volts. I assume I need a fet to switch the atmega with. suggest me one and a circuit? not gate or something.

[Anonymous No.1597837]

what is the circuit in picrel for?

[Anonymous No.1598059]

can run current through a transistor both ways? will there be any problems?

[Anonymous No.1598062]

>>1598059
Only with FETs, and with them I wouldn't unless it's part of a specialised circuit or happens to be a JFET. BJTs do not allow it at all since they're basically two diode junctions together in the first place.

[Anonymous No.1598063]

>>1598062
I see. I will use fets then, unless there is some alternative that is designed for bidirectional current? I need something like the fet where you open or close it by applying a voltage to the gate.
The only alternative i know of that has no problem with bidirectional current is a mechanical relay but that would be shit solution. The currents are in milliamps.

[Anonymous No.1598067]

>>1598063
Any further elaboration on the circuit? Sounds like a JFET is what you're looking to put in the circuit you're proposing, but it also sounds like there might be an easier method altogether. JFETs can be a little troublesome to drive, you have to keep them with a certain voltage bias, and I don't think they're ever truly "off" and instead operate in a sort of "variable resistance" mode.

[Anonymous No.1598072]

>>1598067
I need to put it on an i2c data line and it will act as a valve to open or close the "data pipe"

[Anonymous No.1598075]

>>1598072
Sure using an extra pin or two as an "enable" isn't a better idea? Anyhow it's digital so you don't need something as analog as a JFET.

[Anonymous No.1598076]

>>1598075
What do you mean by enable?
I will use an extra pin to turn the fet on or off. But i cannot do something like stop the communication via software. Basically the when the device loses power the valve needs to shut off, otherwise the "dead" ic will start pulling down the i2c lines, making the whole network ded until it is powered back up or manually disconnected

[Anonymous No.1598081]

>>1598076
A MOSFET logic level shifter might do the trick for this.

[Anonymous No.1598084]

>>1598081
>A MOSFET logic level shifter
Is there some cheap universal one i can get?
basically the lm317 of level shifters. Because i want to keep the circuit as simple as possible

[Anonymous No.1598086]

>>1598084
Just use a normal mosfet and a couple of passives, pic related. You'd hook it up so the "3.3V" line is the Vcc of the slave that may have its power cut, so if that "3.3V" line hits 0V no current can flow. Would that work? Try simulating it in falstad or spice if you're unsure.

[Anonymous No.1598104]

>the part you need only comes at sot23
if i was the god emperor, i would make it a law so it is only allowed to make shitty smd form of a component after it is made as tht

[Anonymous No.1598106]

>>1598104
Change the prefix and check again? LM or LT or ST or whatever versions are made by different guys and could have different packages. But for newer parts you're probably out of luck, so look for an older equivalent I guess.

[Anonymous No.1598110]

>>1598106
tht is dying so we have to learn how to live in the shitty smd future anyway
i guess i will just order a crate of smd to pin adapters and be done with it

[Anonymous No.1598113]

>>1598110
At least the adapter boards are damn cheap. The main gripe I have with SMT is that it's a pain to prototype with; I can't just slap my single IC on a solderless breadboard or protoboard, soldering it on an adapter board renders it useless for anything but breadboarding. It's not like I have any hope of desoldering even a SOT23, let alone a SOIC8.

[Anonymous No.1598119]

>>1598113
buy extra, SMD parts are usually cheaper

[Anonymous No.1598121]

>>1598119
If I was doing plenty of prototyping, I probably would, with one of each of my ICs soldered onto a dual-inline-pin adapter board across those nice hundred-drawer racks. But I don't do enough prototyping for that, nor do I have the room for one of those storage racks, as much as I'd like one.

[Anonymous No.1598124]

>>1598121
yogurt cup full of loose adapter boards is good enough for me
also, a touch of hot air will lift most ICs right off

[Anonymous No.1598125]

>>1598124
>hot air
Maybe some day.

[Anonymous No.1598148]

>>1598113
SOT23 is easy to stick on veroboard

[Anonymous No.1598184]

how the fuck does a syringe with 10l of flux cost $15? how many smds can you solder with that?

[Anonymous No.1598263]

Getting into radio and I need a project to keep me motivated. An idea I had is map out population density by gathering frequencies from devices like phones and other computers and compare the noise throughout the day. Is something like this feasible? Any other interesting radio projects I could give a shot?

[Anonymous No.1598281]

>>1597837
Can anyone help me with finding out what purpose that circuit has?
If I understand it correctly, it latches and makes A drop from 5V to 0V when a current goes into the input, and that you can reset it by pulling B to the ground. But I have no context, and I'm not really sure what A and B are for.

[Anonymous No.1598291]

>>1598281
>But I have no context, and I'm not really sure what A and B are for.
Pic looks like it was pulled from a magazine or textbook, did you take the pic? Is there no surrounding description? Do you know that the 6n139 is an optocoupler?
Basically, why do you have this circuit and want to know what it does if you don't know what A and B are for?

[Anonymous No.1598293]

Can someone here help me out with deriving the current through resistor R4? No one on /wsr/ helped. I don't understand where the negative sign comes from.

[Anonymous No.1598294]

>>1598291
>Basically, why do you have this circuit and want to know what it does if you don't know what A and B are for?
>Pic looks like it was pulled from a magazine
yup. It was one of those quizz question where you're supposed to guess it's function and application
I wasted some time googling it so I don't want to not get anything at all out of it

[Anonymous No.1598295]

>>1598293
I think it just means how it's being measured with reference to the + and - at R4. If the + and - were flipped, then -aIo would also flip positive.

[Anonymous No.1598305]

>>1598293
>the negative sign
>>1598295
Yes, the dependent current source points in a direction opposite to the given direction of Vo.

[Anonymous No.1598316]

>>1598293
It comes from the direction of the currents on your diagram.
Lets assume Is = alpha*I0 for simplicity.
Look at the node with the V0 potential: there are 3 currents LEAVING it: the current Is from current source, the current I3 entering R3 and the current I4 entering R4. So the KCL is as follows:
>Is + I3 + I4 = 0
The current division rule says, that if a current enters a node and is divided among two resistors, then the amount of current on one of them is proportional to the current entering the node times the resistance of the other resistor divided by the sum of resistances of both.
So, in order to use the current division rule, you can ask yourself what current enters that node from the source? It'll be -Is because of its orientation.
Now using current division rule:
>I4 = -Is * R3 / (R3+R4)
>I4 = -alpha*I0 * R3 / (R3+R4)

[Anonymous No.1598325]

>>1598294
>I don't want to not get anything at all out of it
Since you don't know, not getting anything is the proper reward.

[Anonymous No.1598326]

How wifi and bluetooth stuff generate microwaves?

[Anonymous No.1598345]

>>1598295
>>1598305
>>1598316
Thanks fellas!

[Anonymous No.1598371]

>>1598326
they go bleep bloop on a squiggly piece of wire

[Anonymous No.1598385]

>>1598371
I'm asking seriously because I don't think there is a tiny magnetron inside every IoT device and I can't find anything on the web.

[Anonymous No.1598403]

>>1598385
crystal oscillator + frequency multiplier
or less stable oscillator, phase locked to a slower crystal

[Anonymous No.1598405]

>>1598385
>magnetron
Magnetrons are for microwave ovens, not wifi devices.
https://www.amazon.com/RF-Microwave-Circuit-Design-Workspaces/dp/0996446648

[Anonymous No.1598443]

>>1598405
>Magnetrons are for microwave ovens, not wifi devices.
I know that, that is why I was asking reee
>>1598403
Thanks.
>>1598371
retard


I ended up googling and reading some articles and apparently there are inductors on chips, or off chip ones, and both are used in a series of oscilators. And ring oscilators are used too for that frequency range.

[Anonymous No.1598448]

How do I calculate how much power I need to go a certain speed on an electric bike? I guess I'll need to consider the motor, friction between the motor wheel and bike wheel, and some other stuff.

[Anonymous No.1598457]

>>1598184
>10L
millions
>10mL
thousands
is this tacky flux? if so, first, you don't need a whole bunch. second, it's kinda special-purpose and general needs might be better served with a general-purpose flux

>>1598325
that's gayming, not education

>>1598443
monolithic devices almost always generate frequencies via RC-based VCOs disciplined by PLLs

[Anonymous No.1598584]

My dudes, optocouplers are fucking rad.

[Anonymous No.1598588]

>>1598584
totally

[Anonymous No.1598598]

>>1598448
Maintaining speed on a bike doesn't require much power at all. Like a few hundred watts to fight air drag and rolling resistance etc.
But you still are going to need more power than the bare minimum calculated - for hills, wind, and to have decent acceleration.
Did some googling and found this:
https://www.gribble.org/cycling/power_v_speed.html

[Anonymous No.1598602]

Is there something like an RTC module that can communicated over i2c with arduino?
You know the small ones with battery.
Basically what i need is some module where i can say to it "Pull your pin high in 5 hours from now" and then go to sleep and hook arduino interrupt to that pin on the rtc
I could even live without the i2c if it comes down to it

[Anonymous No.1598609]

>>1598602
why, yes, most famously DS1307 or DS3231
there are breakout boards with a battery holder and basic passives, some include a very small serial EEPROM just to use up extra space

[Anonymous No.1598611]

>>1598609
>DS3231
That is literally exactly what i needed.
The arduino is absolute trash at keeping time so this is beyond ideal.

praise our chink overlords

[Anonymous No.1598616]

>hey Ping what sort of pot should we put on this tiny microscopic board? one of those tiny flat adjustable pots perhaps?
>no Pong, let's build a new fucking world trade center on there

[Anonymous No.1598620]

>>1598616
boi i am laffin

[Anonymous No.1598624]

>>1598616
no Pong, why would you want to try to put a 20V adjustment range onto a single-turn pot
besides Wing across the street is already selling that model
oh, eh, Pong, is this only your second board today?

[Anonymous No.1598630]

>>1598624
There are sideways multiturns that could probably be accommodated by shifting the inductor to between the input or output pads and widening the board slightly.

[Anonymous No.1598639]

>>1598293
What book/class is this??
Goddamnit I think i member doing this in circuit analysis, then thought it was a shitty representation of circuits compared to schematics, then when I got to electronics I was again annoyed by hybrid-pi
>they were just trying to prepare me
still, I'm not the biggest fan of this weird 1x1 square layout

[Anonymous No.1598640]

>>1598584
what tidbits made you come to this realization?
just curious

[Anonymous No.1598642]

>>1598113
not that I can recommend it (not always sucessful), but usual I'm able to remove soic(<=16) by just flooding both sides with solder, let cool, then going back and forth til your just pulling it out of solder puddles. Sometimes I'll just pry up one side at a time, bend the legs back after

[Anonymous No.1598643]

>>1596895
On the plus side, now you can never be electrocuted to death

[Anonymous No.1598644]

>>1598642
Would an aluminium shim (similar gauge to solder paste stencils) that you shove under the pad as you reflow the joints be viable? I've never seen anything like it, but a small piece on the end of a thermally insulating rod that you hold and push under legs could be quite effective. With different sizes to push under anything from 0402s to QFP64s.

[Anonymous No.1598651]

>>1598616
> putting a 26 volt difference on a single turn pot
i suppose you despise 1% tolerance components ass well, given that you hate precision

[Anonymous No.1598653]

>>1598584
optocouplers make me hard as diamonds, especially if they are in a DIP6 package

[Anonymous No.1598654]

>>1598584
I wish bidirectional high-speed optocouplers were cheaper

[Anonymous No.1598656]

>>1598148
i dont like vero desu
i much prefer pad per hole, especially when also working with smd parts
but when it comes to transistors, i like to socket them so i can optimize the circuit by choosing different Hfe and leakage.
i mostly build guitar pedals tho

[Anonymous No.1598659]

>>1598656
It's comfy if you plan it out

[Anonymous No.1598660]

>>1598640
Being able to completely separate sensor and power circuits so I can use a CR2032 cell to run a control system for a DC motor with separate power source.

Tiny beginner victories.

[Anonymous No.1598666]

>>1598654
Bidirectional? How fast are they on average?

[Anonymous No.1598671]

>>1597837
its a thyristor-like switching mechanism, which is resettable by pin B. the output is pin A.

ill use an approximate Vsat of 0,25V, for demonstration purpouses

when the optocoupler lets current flow, the voltage on pin 1 drops to 0.6V, the voltage drop over R1 (and R2) becomes bigger than 0,6V thus letting current through T1´s emitter thus turning on T1 (probably in to saturation) which in turn feeds the base of that internal transistor, keeping it turned on, making A around 0,25v which in turn keeps T1 on.
so even if the optocoupler isn´t activated anymore, it can stay on. when B is pulled low enough to make the voltage on the base of the internal transistor less than 0.6 volt, the transistor turns of, and the voltage drop over R1 and R2 become non existent, turning off T1 while A becomes 5V again

[Anonymous No.1598672]

>>1598666
1MHz seems to be the most common.

[Anonymous No.1598676]

>>1598659
i like the flexibility of pad per hole better desu
i always plan it out in my head, im an immage thinker, i can see the layout quite clearly in my head. vero feels to restricted for me, and circuits on vero tend to be much larger than on pad per hole, especially when you mount resistors and diodes upright. pic related

[Anonymous No.1598679]

>>1598671
edit, it´s meant to say ``the voltage on point A drops to 0,25V``, instead of ``the voltage on pin 1 drops to 0.6V``

[Anonymous No.1598688]

>>1598660
If I were doing this with a thermocouple to measure a soldering iron's tip, I'd want the end of the thermocouple to be dereferenced to the soldering tip, and hence dereferenced to ground. To get it floating I'd need to seperate the MAX6675 module from the MCU which records the temperature at the same time as it measures the iron element resistance. The 3 SPI wires would be fine with optocouplers, since they're all one-way, right?

>>1598676
lmao I plan out dotboard on kicad and use the untrimmed, protruding leads as the connectors, sometimes neglecting to solder them in place
>pre-folded vertical glass diode
I give it a 9/10, 10/10 if it's germanium

[Anonymous No.1598695]

>>1598659
Can you recommend a chink store on ali which sells packs of those boards for cheap?
I can only find the ones with separate holes but not with lines

[Anonymous No.1598701]

>>1598695
I got mine locally but there seems to be some deals on Ali for it:
https://www.aliexpress.com/item/Drop-Ship-Wholesale-5Pcs-6-5x14-5cm-Stripboard-Veroboard-Uncut-PCB-Platine-Single-Side-Circuit-Board/32994646633.html

[Anonymous No.1598713]

>>1598688
dot board is best board

[Anonymous No.1598718]

>>1598688
Shit dude idk I'm green as fuck.
I could probably tell you if i stared at the schematic and datasheets for like a day.

[Anonymous No.1598719]

>>1598688
dubs checked
yeah, i have a bunch of 1n4007, 1n4148, 1n34, and 2AA119 diodes in upright orientation. the last two are germaniums, i mainly use the 2AA119 to bias jfet stages, due to their lower Vf. the 1n34 are good for making ``sloppy gates`` just like in the boss HM-2 (heavy metal guitar distortion), pic related, to keep the noise and small signals (like accidentally touching the guitar strings) from passing through the circuit

[Anonymous No.1598720]

>>1598713
>based dotboard user
yeah, dotboard über alles

[Anonymous No.1598728]

>>1598713
Not really, with lines you can save lots of solder and time and use the already made lines and simply cut them with a box cutter where you need separatio

[Anonymous No.1598731]

>>1598728
You shouldn't use solder bridges with dotboard anyway.
Get uninsulated tinned copper wire and lay out traces with them

[Anonymous No.1598740]

with prices like these just build your own sample books. ali prices for 100 resistors are shamefur by comparison

[Anonymous No.1598742]

>>1598740
8 cent + 3$ handling fee + 4$ shipping fee

Ali charges you 3$ for 1000pcs of 0603 resistors, so that's pretty fair

[Anonymous No.1598764]

I just got 50 box caps for €1,45 from aliexpress. They appear to be slightly out of the 5% tolerance they're specified as, but nothing too major.
Is there any drawback to using cheap chink box caps?

[Anonymous No.1598773]

>>1598764
>box cap
are you talking about film caps? I'm no expert but I have used chink mylar film caps and they perform normally. Generally speaking of cheap capacitors, they'll be fine most likely for an individual, but generally they are marginally lacking on ESR, tolerance, longevity, etc

[Anonymous No.1598775]

>>1598773
yeah, box type film caps

[Anonymous No.1598786]

I'm working with some old NMOS chips and have been advised by a reputable party that I need to take static seriously and step up my game.

The chips I got were packaged about as well as you'd expect a chink to treat 40 year old IC's they're salvaging, so I didn't think I needed to do much better, but now I wanna do what's right.
I've been pointed to black foam, and told to look for some that isn't just totally conductive, but that actually resists somewhat so static can dissipate gently.
In looking at black foam, by chance one of the pics has a tester in it, which actually reads "Static dissipative" (however isn't what's shown).

Basically how do I find the right sort of foam, what are keywords a brainlet like me should search for, or am I a dummy and is all black esd foam the same?

[Anonymous No.1598809]

>>1598728
I want size and shape to support the intended function, nothing else.

[Anonymous No.1598817]

>>1598786
https://www.amazon.com/conductive-foam/s?k=conductive+foam

[Anonymous No.1598823]

>>1598817
In this case I want rezistive foam.
I've been told to avoid just anything because some will be far too conductive and static can still do damage.

And ausfag, so
https://www.ebay.com.au/sch/i.html?_from=R40&_sacat=0&_nkw=conductive+foam&rt=nc&LH_PrefLoc=1

[Anonymous No.1598830]

>>1598823
Any foam then?

[Anonymous No.1598861]

>>1598671
>>1598679
Thanks. Figured as much in >>1598281 but hoped anyone might know where it was pulled out from.

[Anonymous No.1598907]

What's your favourite project/circuit that uses the 4017 counter IC?

[Anonymous No.1598960]

Does anyone have advice for how to remove a potentiometer knob that has a stripped setscrew? It's a flathead type & one of the sides of it are completely gone.

[Anonymous No.1598985]

>>1598830
Fuck it, guess it'll do.

[Anonymous No.1599055]

>>1598742
that price may be different if you order 100 each of 170 E24 values that would be useful for a sample stock. throw in some caps just to beat the handling fee
but damn if those little photo album sample books aren't handy

>>1598823
what you don't want is aluminium foil. anything sold as black ESD foam should be suitable for storing sensitive semiconductors. assuming your iron's already ESD safe, just add a conductive grounded desk mat and grounded bondage cuffs and you're good to go

[Anonymous No.1599081]

>>1598960
drill out the set screw. order a new one from mcmaster for $0.5 + $10s&h.

[Anonymous No.1599201]

>>1598654
>bidirectional
Do such miracle devices really exist? Can you give me a chinesium example? I needed bidirectional isolated communication between two ics so many times but never found anything like that on ali

[Anonymous No.1599206]

>>1599201
meh, the closest thing I see is the ADUM1250 which is a 2.5kV inductive isolator for I2C, about a burger each. they also have SPI-oriented isolators with 3 channels in one direction and 1 in the other, on the order of the same price
otoh if all you need is a slow full duplex async UART, just use two jellybean DIP-4 or whatever optocouplers facing in opposite directions. I might have once hallucinated a two-channel opto with one channel in each direction

[Anonymous No.1599215]

>>1599206
>uart
serial is unidirectional right? (so one line only sends or only recieves) yeah, regular octos are great there, but if you want something fancy like i2c, then you are shit out of luck

[Anonymous No.1599225]

>>1599055
>mfw I stuck all my loose chink ICs in aluminium wrapped normal foam and threw them in a plastic drawer
did I fuck up?

[Anonymous No.1599244]

God i hate living in this rural shithole.
>go to local electronics supplies store
>the only electronics supplies store
>hello i would like to acquire this LDO voltage regulator
>"uhh sorry sir, we don't carry those, but might i interest you in this fancy lm317 instead?"
>do you have literally anything else? lm317 drops like all the volts pretty much
>"no sorry only lm317"
>really? can you at least check?
>*annoyed cunt face* "no sorry only lm317"
Every time i want to buy something there it's this exact same conversation.
Unless you are buying the most common parts in the worst like a 10k resistor, they don't fucking have it or even know it exists.
I order 99.9% of all my shit from chinks but if you forget or realize you need some extra part, you have to pause your project for a month to wait for the ship to dock, because this shitty store sure as fuck won't have it

[Anonymous No.1599246]

>>1599244
No online catalog with click and collect? I tried to use click and collect once, first my browser crashed as I was completing the paypal payment so the money went through but this info wasn't forwarded to the store, so I had to pay again and wait for the refund. The site told me that the products would be prepared for me within three hours, so four hours later I turn up and ask about my order, and they spend the next 20 minutes going through the shelves to find each part because they're talentless hacks. Since I could have collected those parts myself in 5 minutes, I don't see a point in doing that again, but in your case it could be a better option.

[Anonymous No.1599302]

>>1599225
5/10 could be fucked, that normal foam could zap chips itself. if you're lucky the foil has been in continuous contact with all pins at all times or it's been humid enough at your location to dissipate charge. if you put them in proper foam you might be alright. have you got a test rig for them?

>>1599244
be nice, sonny, he might be retiring soon

[Anonymous No.1599303]

>>1599302
It was the foam they came in from china. Guess there already was a high chance they're fucked. Don't have a test rig (also they're all kinds of different ICs) but I guess I won't be able to use any of them without testing them first.

[Anonymous No.1599306]

how many of you guys just build stuff for fun vs having an actual problem to solve in your day to day life (as a hobby or personal life improvement, not your job)? I'm having issues figuring out stuff to build so I'm curious about what some of yall do

[Anonymous No.1599342]

>>1599055
>what you don't want is aluminium foil.
Gotcha, thanks. Guy I was speaking to said avoid foil, but also some shitty foams. I'll order some black stuff then, and so long as it's not totally conductive it should be fine.

[Anonymous No.1599394]

>>1599306
Both.
I build stuff for work when I find a need. we kept dropping $300 for a new DMX light controller every year because it keeps burning up. I researched the DMX512 protocol, reverse engineered the lighting system, and built my own to replace it. My controller is on its 3rd year and still running fine.

I'm also heavy into the audio side of the field, so I'm researching and building audio related systems. Such as a standalone 24 bit recording unit, another stand alone 32 bit DAC player.

I'm also making a huge amplifier, that has been a fun ride.

[Anonymous No.1599440]

>>1599306
Keep a note on your phone with project ideas and make a habit of writing them down. You'll have your hands full in no time.

[Anonymous No.1599524]

>>1599306
>I'm having issues figuring out stuff to build
There was this 99 /ohm/ projects list, it's still in the archive. http://i.4cdn.org/diy/1555063132609.png

[Anonymous No.1599610]

what nema code socket is this, its behind the oven, like 220v or whatnot

[Anonymous No.1599614]

>>1599610
i am trying to hook an arc welder socket up to an 220v oven fixure and looking for an adaptor if possible, left is oven, right is welder fixture

[Anonymous No.1599642]

>>1599610
>what nema code socket is this
14-50R

>>1599614
>looking for an adaptor if possible
You can buy a 14-50P to 6-50R pigtail. Or make your own.

1) change the 14-50R to a 6-50R that fits the welder plug.
2) get an oven/range cable with 14-50P end and attach a 6-50R receptacle to the oven/range end.
3) purchase pic related

https://www.corddepot.com/shop/industrial-power/conntek-p1450650-14-50p-6-50r-welder-adapter/

[Anonymous No.1599647]

>>1599642
My wording was poor on this.
1), 2), 3), were choices - not steps
Google search for "14-50P to 6-50R Pigtail Adapter"
to find other places to purchase if you choose 3)

[Anonymous No.1599649]

>>1599610
>what nema code socket is this,

[Anonymous No.1599662]

>>1599649
I apologize if this isn't the best place to ask, but I'm overwhelmed by the sheer volume of information that I've already found. I'd appreciate it anyone could just tell me what to do.

I'm working on setting up an indoor garden, but it's not weed. And since it's not weed, I can't afford to spend a ton of money this time around. I've been looking at options such as cutting down larger and cheaper heatsinks to use with COB LEDs, LED strip lighting, and plain ol' LED bulbs, as well as resigning myself to just using fluoros again. It seems like regardless of the lighting I'm looking at about $150 to cover a 2'x4' area with 20-30w/sqft, and then ~$15/mo for electricity on LED or $25/mo on fluoros. I realize that probably doesn't sound like a lot to many of you, but my disabled veteran ass only has $100/mo of expendable income to start with.

[Anonymous No.1599716]

>>1599662
Aluminum sheets, window aluminium railings and LEDs+drivers from china. I'm a third worlder that made a tomato grow on one of those plastic bins with those things, so you should do well. I think window railings or thin sheet metal are not expensive in america. Also
>scrap
>pc fans
>pc power supplies
>regular fans people throw away just because
>every single electric(onic) thing nowadays has atleast 1 small heatsink innit.

[Anonymous No.1599719]

>>1599716
>already assembled ones
>https://pt.aliexpress.com/item/Barato-Estufa-Hidrop-nica-50-W-100-W-150-W-Planta-Crescimento-Luz-Led-Barra-de/32965686779.html
>regular 12v ones (I have these)
>https://pt.aliexpress.com/item/CLAITE-50-W-COB-LEVOU-Chip-Espectro-Completo-Planta-Cresce-A-Luz-Branco-Branco-Quente-DC12V/32970680980.html

And there are many others, just search for them on ali or amazon idk. And mine were supposed to draw ~5A at 12V but only draw 3, so I'd derate power ratings by 20-ish percent for plant calculations, but buy a properly rated psu.

[Anonymous No.1599721]

>>1599719
And honestly, I live in a tourist city with 2019521095 homeless drug users that can smell copper from 2 miles away and I still manage to find some useful salvage, I'm sure in america you can find much more if you look for it. Just Summon your inner Ricardo or Pajeet and you'll manage bro.

[Anonymous No.1599722]

>>1599662
how long is all this meant to last you? a couple of seasons or basically forever?
white general-purpose COBs are the way to go for efficiency these days. look around on chinkbay, you can find some fair to good emitters for pennies per watt (Hong Li looks like a good manufacturer) and constant-current drivers for a dime or two per watt
https://www.aliexpress.com/item/Freeshipping-Constant-Current-AC100V-250V-LED-Benis-Driver-Output-DC30-36V-1-6A-for-50W-High-Power-Benis/830904277.html (you might need three)
instead of thinking in terms of heat sinking, think in terms of heat transport. are you ventilating the grow area to the outside? if not, is your aircon bill going to go up if the heat from the lamps just dissipates into your living space? in special situations, water cooling with a window-mounted radiator might save you money over the long term

[Anonymous No.1599755]

>>1599722
>white general-purpose COBs are the way to go for efficiency these days
They're better for grow-lights than the blue-red lights?

[Anonymous No.1599786]

>>1599755
the home weed growers seem to prefer plain whites and they're generally the ones to nerd out over that sort of thing

[Anonymous No.1599788]

If i draw over 1a from my dc dc step up power source it starts making angry hornet sounds but it is rated for what I want to draw from it. Can I safely ignore the scary sounds?

[Anonymous No.1599789]

>>1599786
If you'll allow me to be presumptuous, I wouldn't exactly trust cannabis growers to be educated on many subjects, especially not ones as technical as a combination of photomorphogenesis and LED physics.

[Anonymous No.1599795]

Anyone here from nyc?
I've got a 2 yr degree in electrical engineering tech but cant seem to find a worthwhile job.

[Anonymous No.1599806]

>>1599795
>worthwhile job.
what? you think you are too good for digging fitches and flipping burgers because you can solder a wire?

[Anonymous No.1599808]

>>1599806
Das rite papi

[Anonymous No.1599809]

>>1599788
the current rating you saw was the rated switch current of the converter IC, which for step-ups pertains to input current. you're overloading it and should treat those angry hornet noises as a groan of overstress

[Anonymous No.1599816]

>>1599806
Let me guess you got your 4 yr degree?

[Anonymous No.1599819]

>>1599816
You need masters degree to flip burgers?

[Anonymous No.1599850]

>>1599808
go back to Puerto Rico and/or California and fix your own shit

[Anonymous No.1599858]

>>1599716
This is basically where I'm at currently, except that I used steel drywall edging. 5050 blue cree spaced about 1' (2.5cm) sprouted everything except mint for some reason, but left spinach leggy and everything underdeveloped except brocolli, which would indicate to me that it's producing levels of light intensity relative to partial sun.

>>1599722
I'm supposed to be doing a determinate hearing on military disability this summer, so I may be able to upgrade significantly later. Right now I just really need a project.

I thought the advantage to COBs was that the driver is on board? Or is that just the ones that I've been looking at?

>>1599755
>>1599786
People mostly see green with some red and blue, plants 'see' in mostly red and blue with some green, NIR and UV, and possibly other spectra. I don't know if any commercial light is actually properly balanced for plant growth, but I'd guess that warm white with supplemental blurple would be close.

[Anonymous No.1599859]

>>1599858
I've done a bit of plant bio, and can tell you that as well as photosynthesising mostly at red and blue, they also have flowering and seeding cycles based off how long the nights are, which I believe are triggered by two sensors at red and far-red light respectively. I think you can trigger daffodils to flower early if you flash red light at them at night; they'll think that the night was a shorter, spring or summer one, but this doesn't work if you flash them with far-red light afterwards, for whatever reason. Then I think they respond to blue or green light by bending/growing towards it. So if you wanted maximum control over a plant you'd probably have RGB+extra LEDs and have a fairly dynamic controller to power them.
Still, for the purpose of photosynthesis, there's no reason to use a phosphor that emits light at any wavelength other than those that are most strongly absorbed, so for maximum power efficiency it's likely that red+blue lights are best to that end, but having the other colors for finer growth control would be preferred.

[Anonymous No.1599865]

>>1599789
Canna farmers really come in all types. I've seen potheads that just bury diapers and seeds in the woods and hope for the best, but I've also known a few people that have hydrosetups that give substantial and consistent yields well above standard projections for canopy size, so they must have a seriously strong comprehension of all aspects of the plants' needs.

>>1599859
>flowering and seeding cycles based off how long the nights are
My primary focus is on tomato and spinach, neither of which is affected by light cycles in the same manner. A larger issue is that they both bolt/flower based on temperature, and that gives me a very tiny window to work with to keep they both in edible states.
>I think they respond to blue or green light by bending/growing towards it.
That's my understanding, that having a larger proportion of green light indicates shading by taller plants and promotes stretching, but excluding it completely reduces stem strength.
>so for maximum power efficiency...
I'd like to see a commercial light that's properly balanced for plant growth, but different plants have different light requirements also. Black basil and Japanese maple don't follow the traditional spectra at all, and most plants have slight variations on the typical 'mostly red/blue' standard anyway. Currently, most of the people willing to drop serious cash on grow lights are producing cannabis though, so that's where the light industry is going to focus their development. I have serious doubts that phosphor spreading or RGB either are very good, since phosphor creates a lot of wavelengths that aren't necessary and RGB really only produces those three wavelengths and it's the relative emissions that only give the illusion that a variety of color is being produced, whereas plants aren't using cones and a visual cortex to correct for those values. If I'm understanding what I've read, anyway.

[Anonymous No.1599874]

>>1599865
Well I was thinking you might want to turn off red lights at night, but keep the blue ones on, hence necessitating individually controllable lights.
True you'd have to be lucky that the RGB wavelengths happen to fall on the peaks of the chlorophyll absorption, but a phosphor-based RGB might work for that instead. Picking the right single phosphor (instead of mixing a bunch like in a white LED) to stimulate at the peak of absorption for the two chlorophyll bands might be possible, though for far-red I think raw red LEDs might be the way to go.
I wonder if using pumice atop the soil or lighter colors everywhere would help to reflect the light around and decrease losses?

[Anonymous No.1599927]

>>1599858
it's "chip on board", i.e. the LED dice are assembled onto a printed circuit on a substrate in series/parallel circuits
drivers are sometimes included as a value-add. they aren't usually very versatile or efficient drivers but some can be hacke for e.g. dimming
with light engines you BYO driver, which is great for signmakers, interior designers, stage electricians and others who require better control over a lot of light
as a general rule, you can get more lumens per watt and longer LED life when you overbuild and underdrive

[Anonymous No.1600032]

I am confused.
This voltage regulator has a dropout of 400mv.
Then why does the spec sheet say the operating voltage is 4.3 - 16?
3.3V+400mv is 3.7V on the input, not 4.3

[Anonymous No.1600038]

>>1600032
> Then why does the spec sheet say the operating voltage is 4.3 - 16?
It doesn't say that (at least, not in that table). But it's safe to assume that the regulation is somewhat worse below 4.3V (given that they don't cite any figures below that value).

At a minimum, don't expect to pull 1A from it without a significant voltage drop. If the *nominal* drop is 400mV, it probably means 400mV plus whatever voltage it drops due to resistance, as it can't reduce the variable drop below 400mV to compensate for that.

[Anonymous No.1600050]

>>1600038
>It doesn't say that
What does the "line regulation" value mean then?
This regulator only outputs 500ma and is hardcoded to output 3.3v and i only need about 300ma tops anyway

[Anonymous No.1600071]

>>1600050
The line regulation is specified for Vi=4.3V...16V and for Io=5mA. Under these conditions ∆Vo should be typ. 3mV and max. 16mV. That's what it means, nothing else.

[Anonymous No.1600082]

>>1600071
Well i really hope so, since i ordered a whole crate of them and i need them to piss out 3v3 even if i feed them something like the 3.8v

[Anonymous No.1600089]

>>1600082
That may well be so.

[Anonymous No.1600092]

>>1599850
Not a filthy puerroreekan and i'm not a mexican.
I guess you cocksuckas have no advice for a fellow grad. Just wanted to know what type of job you currently have.

[Anonymous No.1600113]

>>1600089
Nice.
that will do

[Anonymous No.1600162]

Okay, how do I stop hoarding shit from recycler?
This time I got fully functional LCD monitor. I thought that it is shot and it is capacitors, as always, but no, it is OK.

[Anonymous No.1600283]

>>1600092
>grad
dropped out of high school, my dude

>>1600162
have you contacted your local substance abuse hotline
seriously tho you could probably find good second homes for these things in your local alt newsweekly or on ebay or whatever, and you can put any cash back into upgrades

[Anonymous No.1600347]

>>1600162
Certainly better than hobbies that consume value. I'd sell them on ebay or whatever.

[Anonymous No.1600390]

The mains for the light fixtures go through a plastic tube that's bent and juts out from the ceiling.
Can I just push back the wires and drill into the tube to enlarge the hole for a different light fixture? Or are we getting into illegal territory?

[Anonymous No.1600392]

>>1600390
/ohm/ RULE 0
>Electrics ≠ electronics. Home appliances/sparkies to /qtddtot/ or /sqt/.

[Anonymous No.1600393]

>>1600392
Whoops.

[Anonymous No.1600532]

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