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Need a 100v voltage regulator? Answered

So what I am trying to do is make a variable power supply from a computer PSU, I've done thise before minus the variable part.

I need a voltage regulator that will limit 200 or more volts to 100 volts DC.

I also need different variable voltage regulator that will allow me to adjust this from 0 to 100 volts, they usually have a circuit in the datasheet that uses some resistors and a potentiometer.

So, are there voltage regulators like this? If not what is another way to do it?


How are you getting 200V out of a computer PSU? The most you can usually get it 24V between the +/-12V rails.

It's highly unlikely that there is a variable linear voltage regulator like you are suggesting that will work at anywhere near 200V, and such a part would likely run extremely hot.

You are probably going to have to design your own regulator, or boost the 12V rail up to 100V.

The caps charge at 200 volts and it is a nice steady source.

Also DEADLY, that's not mains isolated. You HAVE to HAVE an isolating transformer.

PSUs seem to be the question of the week here.

Yes you can do it five ways.

First you can regulate voltage by sending your source voltage through a bridge rectifier to an electrolytic capacitor and controlling the output with a pot connected to a transistors base.

Unfortunately this won’t compensate for draw changes in draw unless you use a variable regulator to control the transistor, examples should be in the datasheets.

The second way go to this website and download the datasheets for voltage regulators:


Enter LM317 in the search and download the datasheet.

You can follow the circuit examples in the data sheets.

The third way can use the voltage regulator schematic as a template for building your own a variable voltage regulator. You better be good at electronics for this.

The fourth way is to build a variable regulated power inverter. You better be good at electronics for this.

And the last way is to search for components with in your specks at supplier sights like Mouser.


Enter “variable voltage regulator” and refine your search or look for one that will do what you want. I couldn't find one.

Make a transformer isolated 100V dc supply - potentially lethal though. Then add a linear regulator. What current ?