How to measure charging of Cockcroft Walton Multipliers?

[shrinky]

How do you measure the voltage of a cockcroft walton multiplier over time to observe the charging behavior? Does measuring with oscilloscopes discharge the capacitor hence you can't observe the charging or not?

 

[NascentOxygen]

The oscilloscope doesn't impose much loading on the circuit. You are wanting to observe the actual pumping up? That will be a short term transitory waveform. Using a CRO with differential inputs might be handy, if you wish to observe all waveforms around the circuit.

 

[shrinky]

Yeah. Ideally I'd like to see the oscillation with amplitude offset increasing as time goes on.

Right now I have a simple half wave multi stage multiplier set up. I can measure the rectification part, so the sine wave only goes to the positive and not negative, but I don't see the amplitude increase so that the dc offset is always zero essentially.

It could be my driving frequency isn't correct perhaps?

Rhetorical I guess but is it better to measure the voltage across the capacitor at the highest stage or measure the potential relative to ground.

 

[NascentOxygen]

Yeah. Ideally I'd like to see the oscillation with amplitude offset increasing as time goes on.

Well, it's a transient, so unless you have a storage CRO or a synchronised camera, you won't see it.

Right now I have a simple half wave multi stage multiplier set up. I can measure the rectification part, so the sine wave only goes to the positive and not negative, but I don't see the amplitude increase so that the dc offset is always zero essentially.

Are you saying it's not working?

It could be my driving frequency isn't correct perhaps?

It shouldn't matter.

Can you post your circuit schematic?

Rhetorical I guess but is it better to measure the voltage across the capacitor at the highest stage or measure the potential relative to ground.

Unless your driving source is floating, you can't connect the CRO across any ungrounded element.

 

[pmacias]

I would suggest using a high voltage probe or a voltage divider circuit to measure the voltage of a Cockcroft Walton multiplier over time. This will allow for accurate measurements without discharging the capacitors.

Using an oscilloscope to measure the voltage may indeed discharge the capacitors, depending on the oscilloscope's input impedance and the sensitivity of the capacitors. Therefore, it is important to carefully select the appropriate oscilloscope settings to avoid discharging the capacitors.

Another option would be to use a data acquisition system with high input impedance to continuously monitor and record the voltage over time. This would allow for a more detailed observation of the charging behavior without the risk of discharging the capacitors.

In any case, it is important to carefully consider the equipment and techniques being used to measure the charging behavior of a Cockcroft Walton multiplier in order to obtain accurate and reliable results.