Designing a Voltage Multiplier: Choosing Components and Safety Considerations

[helofrind]

have a few questions about designing a voltage multiplier. let's say I want 1kv output from 9v battery source.
- do all the caps have to be electrolytic caps?
- how to choose what caps to use?
- how to choose what diodes to use?

 

[redwan hasan]

have a few questions about designing a voltage multiplier. let's say I want 1kv output from 9v battery source.
- do all the caps have to be electrolytic caps?
- how to choose what caps to use?
- how to choose what diodes to use?

as far as i know you can use any type of capacitor you want. the value might be different though.

and you can also use small transformer to do this. first use a switching circuit consisting of transistor and caps to make it AC then feed it into a transformer of proper number of turns. the current will be really small but you should get around 1kv.

 

[helofrind]

Thanks, I wasnt sure if electrolytic capacitors had to be used, because that is all I see people using. I would consider stepping up the voltage through a tranfromer before supplying voltage to the multiplier, but is what i don't know is voltage ratings for the diodes and capacitors. or does that even matter?

 

[redwan hasan]

Thanks, I wasnt sure if electrolytic capacitors had to be used, because that is all I see people using. I would consider stepping up the voltage through a tranfromer before supplying voltage to the multiplier, but is what i don't know is voltage ratings for the diodes and capacitors. or does that even matter?

that should matter, you can check datasheet of any product to find out its max ratings.

 

[davenn]

on the HV output side, you should be using disc ceramic capacitors with the appropriate HV ratings
you are not likely to easily find electrolytics with voltage rating at anything over a few 100 volts ( up to ~ 500V are common and often used in SMPS's.
But you need ones rated at several kV and that's why you use the appropriate rated disc ceramics

I'm a little concerned that if you don't understand the basics like that, should you really be playing with HV ?
please be very careful !

Dave

 

[sophiecentaur]

I'd put it stronger than that.
The OP's question is completely open ended and should be treated as risky. There is the strong possibility of killing someone with a 1kV source unless the current output is limited to less than a very few mA. Anyone who is not qualified to work with live mains voltages should avoid playing with 1kV sources unless the conditions are 'just right'. If the OP is asking these kind of questions then he is unlikely to know what is 'just right'.
Even if the 9V source is only a PP3, the energy from it that can be stored in a capacitor at 1kV can be lethal. I think the thread should be moderated.

 

[helofrind]

I appreciate the concerns. I am an electronics technician and have taken plenty of classes on the safety side of high voltage, the highest voltage I work with is about 270V DC. I have built a voltage multiplier in school with smaller potential, but they did not go into detail with it at all, it was just a quick lab. of corse I would limit the current to as low as a few mA to higher micro . definitely wouldn't use mains, I plan on using a DC source and oscillator to a step up transformer. I do want to experiment with the high potential side of electronics. I don't plan on jumping straight into a circuit with that high amount of voltages just yet. I would like to practice and gradually get to the fun stuff with high respect to safety. the reason I was asking about the electrolytics is because I have never seen anything over 500V rating, but yet all i have seen is people using electrolytics, but any schematic I have seen, has never shown polarized caps. I guess my main question was do the ratings of the components need to be higher than the output? again thanks for any answers also I appreciate the concerns.