# How to measure charging of Cockcroft Walton Multipliers?

• shrinky
In summary, the conversation is about measuring the voltage of a cockcroft walton multiplier over time to observe its charging behavior. The use of oscilloscopes is discussed, with the suggestion to use a CRO with differential inputs to observe all waveforms. The speaker also mentions difficulties in seeing the amplitude increase and asks for advice on the best way to measure the voltage. The conversation ends with a discussion on the potential of measuring the voltage across the capacitor at the highest stage or relative to ground.

#### 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?

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.

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.

shrinky said:
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.

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.

## 1. How does a Cockcroft Walton Multiplier work?

A Cockcroft Walton Multiplier is a type of voltage multiplier circuit that uses a series of capacitors and diodes to generate a high DC voltage from a low AC voltage source. The capacitors are charged and discharged in a specific sequence, resulting in a multiplied output voltage.

## 2. How do you measure the charging time of a Cockcroft Walton Multiplier?

The charging time of a Cockcroft Walton Multiplier can be measured by using an oscilloscope to monitor the output voltage. The time it takes for the output voltage to reach its maximum value can be used to determine the charging time of the multiplier.

## 3. What factors can affect the charging time of a Cockcroft Walton Multiplier?

The charging time of a Cockcroft Walton Multiplier can be affected by several factors, including the capacitance and resistance values of the components used, the frequency of the input voltage, and the quality of the diodes.

## 4. How can you improve the charging efficiency of a Cockcroft Walton Multiplier?

The charging efficiency of a Cockcroft Walton Multiplier can be improved by using high-quality capacitors and diodes, reducing the resistance in the circuit, and optimizing the frequency of the input voltage. Additionally, ensuring that all components are properly connected and in good condition can also improve charging efficiency.

## 5. Can the charging time of a Cockcroft Walton Multiplier be calculated?

Yes, the charging time of a Cockcroft Walton Multiplier can be calculated using the formula t = RCln(2N), where t is the charging time, R is the total resistance in the circuit, C is the capacitance of each stage, and N is the number of stages in the multiplier.