Author Topic: Capacitor Polarity Question  (Read 822 times)

0 Members and 1 Guest are viewing this topic.

Offline bostonmanTopic starter

  • Super Contributor
  • ***
  • Posts: 2083
  • Country: us
Capacitor Polarity Question
« on: February 22, 2022, 12:28:52 am »
I have a silly question about C90 in the attached (circled in red).

This is the power supply section from a C64, and I want to confirm why the positive side is on the left. Usually if I see a capacitor in series, it's non-polarized, and, a polarized capacitor always connects to the positive; unless it's a negative voltage then the positive is to ground.

This could be an incorrect statement, but this may be a first time I've seen a polarized capacitor in 'series'.

I forgot the name of that circuit, however, I'm assuming the positive is on the left because it's the higher voltage, correct?
 

Offline Benta

  • Super Contributor
  • ***
  • Posts: 6257
  • Country: de
Re: Capacitor Polarity Question
« Reply #1 on: February 22, 2022, 12:52:17 am »
The positive is on the left, because there's a"+" symbol there.
Nothing wrong with the schematic, it's a charge pump voltage inverter circuit.
 

Offline bostonmanTopic starter

  • Super Contributor
  • ***
  • Posts: 2083
  • Country: us
Re: Capacitor Polarity Question
« Reply #2 on: February 22, 2022, 02:09:50 am »
I meant electrically why is it on the left?

What is the reason it's not connected to the right side instead?
 

Offline ledtester

  • Super Contributor
  • ***
  • Posts: 3248
  • Country: us
Re: Capacitor Polarity Question
« Reply #3 on: February 22, 2022, 02:30:20 am »
It's essentially because the left side of the cap is connected to the "+" terminal of the bridge CR4 (through a diode). That means it will always be greater than either of the AC inputs (pins 2 and 4). Since the right side of the cap is connected to pin 4 it makes sense to have the left side of the cap to be +.

« Last Edit: February 22, 2022, 02:33:05 am by ledtester »
 

Offline Damianos

  • Frequent Contributor
  • **
  • Posts: 268
  • Country: gr
Re: Capacitor Polarity Question
« Reply #4 on: February 22, 2022, 01:19:50 pm »
Have a look here Voltage doubler especially the two first circuits. Study them a little and then add the rest of the circuit (its easier to do that step by step).
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf