Increase the maximum voltage rating of semiconducter

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Discussion Overview

The discussion revolves around methods to increase the maximum voltage rating of transistors or thyristors in DC applications, particularly in the context of high voltage experiments involving electrets and molecular structures. Participants explore various approaches and considerations related to high voltage components.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about increasing the maximum voltage rating of transistors or thyristors, specifically in their off state.
  • Another participant suggests that methods to achieve this depend on the specific application and requests an example of the required voltage rating.
  • A participant mentions the need for high voltage components for studying electrets and expresses concerns about the limitations of available transistors and thyristors.
  • There is a proposal to use a transformer and a voltage multiplier, although concerns about the complexity and lag in output are raised.
  • One participant states that they need to work with voltages over 10 kV and will be using pulse signals.
  • A later reply suggests that using a voltage multiplier with a suitable transistor could be a viable solution, although the participant expresses uncertainty about their understanding.
  • A schematic for a repetitive pulse generator in the style of a Marx generator is shared, indicating potential designs for high voltage applications.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to the problem, with no consensus reached on a definitive method for increasing voltage ratings. Some participants share ideas and solutions, while others raise questions and concerns about safety and complexity.

Contextual Notes

Participants mention the importance of safety when working with high voltages, indicating that there are specific rules and precautions that should be followed, although these rules are not detailed in the discussion.

Who May Find This Useful

This discussion may be of interest to individuals working with high voltage electronics, particularly in experimental physics or engineering contexts, as well as those exploring the use of transistors and thyristors in high voltage applications.

HVlad
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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.
 
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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
 
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 can`t 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.
 
HVlad said:
So obviously, I need to use high voltage components.
What voltage? What frequency? What waveform, sine or square?
 
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 haven`t worked with these kind of circuits I didn`t 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. :))
 
HVlad said:
Mods:
Truly sorry for taking up space and then answering my own question! Feel free to delete the thread. :))
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? :smile:
 
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.
 

Attachments

  • BJT_Marx.jpg
    BJT_Marx.jpg
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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, I`ve 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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