I would like to make an adjustable power supply to control the brightness of some LEDs. I would sense the voltage with the ADC and adjust the PWN output accordingly. Similarly to how a proportional integral derivative loop works. I want to place the sensing wire and the LED power supply wire between the two caps so the caps stabilize the voltages. The caps can handle 5v each so 10 in series at half the capacitance. I attached 2 versions of my idea; one with an NPN transistor and one with a PNP and NPN transistor. I was wondering which would be better for this idea and also looking for general feedback and tips. I didn’t include in-series resistors before the LEDs but they will be there.
You are trying to draw DC current from the junction of two capacitors. How can that work?
Seemed odd at first to me too, however my breadboard doesn't lie. I think I'm actually just going to drive the LEDs with the PWN. Not directly but through a transistor.. and the caps just filtering.
You may be miswired or your capacitors are bad or installed backwards. Otherwise, the caps will simply charge up and the LEDs will go out.
What is a "PWN"?
PWM* Pulse width modulation. Anyways, it appears that it only works with the aerogel super caps, I tried some tantalum caps and it didn't work.(which it shouldn't) Electrolytic caps seem so let some through too I just discovered. I understand how caps are made, I've even built one... Maybe mine are are shot and letting current through? I have abandoned the original idea, going to use PWM and an a transistor.
And USE A RESISTOR!
polymorph: You may be miswired or your capacitors are bad or installed backwards. Otherwise, the caps will simply charge up and the LEDs will go out.
Of course a 1F capacitor will take a while to charge, but charge it will and the current fade to just leakage.