/diy/ - Do It Yourself

>>1181658
cont.

Since R = V/I, the series resistance is 1.7/0.76, or 2.24Ω. This is quite low, and the power across it will be above 1W. Here you're really starting to pull power, with a total dissipation of the circuit in standby mode sitting at almost 4W. This is the minimum value for our resistor.

Try larger resistors until the voltage across the Zener is no longer 3.3V, then go back again to a value where it is 3.3V under load and idle.

>>26449

I'm just thinking the 'big transistor with a zener for regulation' (pic related). I don't know much (at all!) about PSU design, hence wanting to use the PC PSU if I can. Feel free to tell me I'm doing it wrong (and why/a better way).

>>26430

OK, cool. Sounds like a resistive element is a better idea. I dunno why my first instinct was a peltier, tbh..