# Increase the maximum voltage rating of semiconducter

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1. Apr 13, 2017

### HVlad

Hello,

I was wondering if there is any way of increasing a transistor or thyristor maximum voltage ratting in DC?
Thanks.

Edit: Just to be more precise, I am referring to the off state. I know you can the on state via a resistor.

2. Apr 13, 2017

### Baluncore

Welcome to PF.

Yes, there are ways, but how you do it depends on why you need to do it.
Can you give an example where you need a higher voltage rating.

Voltage multipliers such as Marx and Cockcroft-Walton_generators build ladders for high voltage.
https://en.wikipedia.org/wiki/Cockcroft–Walton_generator

3. Apr 13, 2017

### HVlad

Thanks for the welcome.

Basically I want to study electrets, molecular structures, interactions, etc. So obviously, I need to use high voltage components. The reason I am asking is because I need to control when and how some plates are charged but the transistors and thyristors I found are underrated. Oh and I cant use relays because of the frequency of some experiments and the higher cost.
I was thinking of using a transformer and a voltage multiplier then control the commutation before the transformer but that would mean a lot of transformers and a lag at the vm output.

4. Apr 13, 2017

### Baluncore

What voltage? What frequency? What waveform, sine or square?

5. Apr 13, 2017

### HVlad

The voltage will be a bit over 10 kV. I will be using pulses.
In any case I think I figured it out and this is kinda embarrassing. It was right in front of me but since I havent worked with these kind of circuits I didnt notice. For those that might do something similar:
If using a voltage multiplier just insert a transistor that can withstand the input voltage(+ error margin) and it should be fine. Obviously, if I got this wrong do correct me.

Thank you, Baluncore, for your time and input.

Mods:
Truly sorry for taking up space and then answering my own question! Feel free to delete the thread.

6. Apr 13, 2017

### Staff: Mentor

Not a problem. Welcome to the PF.

Please do be careful if this is the first time you are working with high voltages like 10kV. There are some rules for working with such voltages -- can you mention a few of the rules that you know of to help keep you safe?

7. Apr 13, 2017

### Baluncore

Attached is a schematic for a repetative pulse generator in the style of Marx.
A small positive trigger produces a short high voltage negative pulse.
It is modeled here with a few low voltage stages, but could be built with say 16 stages of 650V transistors and components.

#### Attached Files:

• ###### BJT_Marx.jpg
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8. Apr 17, 2017

### HVlad

Sorry for the late reply, I was kinda busy the past few days.

berkeman:
Thanks for the heads-up, but yeah. I should be fine, Ive worked with even higher voltages before; it`s just that although I understand electronics I usually have someone make the circuits.

Baluncore:
Thanks a lot mate! I owe you one.

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