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March 2017

Getting Started With High Voltage

I would like to experiment with high voltage projects, but all my experience in building power supplies is for low voltage (typically 5 or 12 volts). I’d love a schematic for a high voltage power supply that could produce between 0 and 250 volts safely. Also, any safety pointers for getting started would be appreciated.

#3171
Ed Warren
Everett, WA



Answers

You want to be extremely cautious experimenting with high voltages as they are lethal and can be fatal. Rather than trying to construct a high voltage supply, which could be dangerous, you might consider a variable transformer such as the Volteq #1KVA_110V/250V (www.volteq.com), which costs about $70. This transformer plugs into a standard 120 VAC outlet and provides an adjustable output from 0 to 250 VAC, and provides isolation from the AC power grid. If you want DC voltage, you can construct a simple bridge rectifier circuit. However, there are many more interesting projects that use 5 - 12 volts, and I suggest you pursue some of them instead.

Bob Stewart
Mancos, CO

You didn’t indicate how much current you are expecting from the supply? Searching the internet I found the referenced schematic for a 300 VDC variable voltage supply that will deliver up to 100 ma. Circuit is for 220 VAC mains but we can substitute a step up transformer for operating with a 120 VAC mains. I have attached a parts list reference from Digikey that should do the trick. Due to the high voltage involved, you should put the components inside an enclosure, such as a Bud Industries box and bring the output up to a couple of banana type jacks or terminal block. You can also mount the pot on the outside of box and add a knob to it. Transformer is the most expensive component and can be sourced from other suppliers if you need to reduce costs. Hope this helps!

Schematic: www.eleccircuit.com/the-variable-high-voltage-power-supply-0-300v/
Parts List: www.digikey.com/short/327wpp

Doug Foreman
Warren, MI

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