# How to make a high voltage pulse generator?

#### Terrox

Joined Oct 25, 2017
4
Anyone know a schematic that can output a square wave of 100v and can reach up to 15amps?

The purpose of this is to make my own generator that will provide a magnet with voltage and amps to make a magnetic field that will interact with another magnets magnetic field.

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#### crutschow

Joined Mar 14, 2008
23,157
That's 1.5kW of power.
Will this be a continuous square-wave?
What frequency?

#### Terrox

Joined Oct 25, 2017
4
Like maybe 20Hz and it will be a continuous square wave. We are hoping to somehow tune the frequency to match with something in our project.

#### wayneh

Joined Sep 9, 2010
16,102
When you say square wave, do you mean on and off like flashing a DC light bulb, or alternating polarity, like AC only square?

#### Terrox

Joined Oct 25, 2017
4
When you say square wave, do you mean on and off like flashing a DC light bulb, or alternating polarity, like AC only square?
I mean the on and off one.
We want it to go for 20Hz bec we want 20 pulses per second.

#### wayneh

Joined Sep 9, 2010
16,102
I mean the on and off one.
We want it to go for 20Hz bec we want 20 pulses per second.
Alright, let's take for granted that you have a DC power supply capable of 15A at 100V. If you do not, that's a whole separate discussion. Discussions of mains-direct circuits aren't allowed here. Just sayin'.

Once you have the power supply, the rest is 'easy'. You need a 555 timer circuit called an astable multivibrator. You'll need a 10-20V DC supply for this circuit. The 555 circuit will generate the 20Hz square wave. You'll feed the 555 output to the gate of an N-type power MOSFET rated to handle the power level you need, ie. to 200V and 30A. (The 2X increase is a safety factor.) The MOSFET is like a light switch in this circuit, with the switch being flipped by the 555 signal. The MOSFET you need is big enough that it will probably cost a few dollars, maybe up to \$10. You may want to mount it on a heat sink.

Because you are switching an inductive load, you'll need to protect the MOSFET from the large inductive spike that occurs when you remove power from the coil. For small loads this is usually just a diode in reverse bias across the poles of the inductor. The diode should be rated for at least double the applied voltage and double the load current. Yours is not a small load and I'm not comfortable specifying the protection you need here. Hopefully someone else will chime in to recommend adequate spike protection. The inductance value of your coil is required to specify a recommend diode. So the more details you can provide, the better advice you'll get.

#### BR-549

Joined Sep 22, 2013
4,936
How bout 8 auto batteries and a switch.