/diy/ - Do It Yourself

>>2397040
It's not waterproof enough to survive etching anyhow, unless you buy some sort of fancy inkjet ink. Gonna be expensive either way.

>>2397057
> i cant get ferric chloride.
Muriatic acid is the common method, but you can probably do membrane electrolysis with iron metal and salt water to make ferrous chloride, hydrogen gas, and sodium hydroxide. Then you just bubble air through it or leave it with the lid open for ages. Need a good membrane for that though, think terra-cotta works sufficiently well with iron compounds but I'm no expert. The high pH of the basic side may result in iron hydroxide forming, which wouldn't be ideal. Can't really acidify it though. Might be better off electrolysing salt water into sodium hydroxide and hydrochloric acid and then using that HCl to make the ferric chloride the normal way.

>>2397058
>>2397059
Read the datasheet of your chosen transistor instead of relying on a simplistic simulation. For example, a BC547 has a current of about 200pA on average, maximum of 15nA. Compare that to a BSS138 MOSFET and you've got current as high as 500nA max. Still a non-issue in most circumstances though.

Also why use a 1kΩ resistor on the base? Looks like a massive waste of current.

>>2397151
>theyll switch between the input voltage and ground at super sonic frequency, and then use a low pass at 20kHz to make it in to audio again
How is that a compressor? Just sounds like a simplistic class-D amp. I thought compressors were just automatic-gain-controllers, basically voltage-controlled-amplifiers. Maybe some nonlinearity from soft clipping too, idk. A JFET or OTA design would seem conventional. Single balanced diode mixer if you're a hipster.

Is there some other definition of compressor I'm not understanding?