DIY Multi-Purpose High Voltage Transformer

Introduction: DIY Multi-Purpose High Voltage Transformer

So I recently acquired an old non functioning microwave with the intent of using the transformer windings as coils for a wind turbine generator. But upon further thinking it seemed like kind of a waste of a perfectly good step-up transformer. So I decided to keep it as is, and make it a little bit more user friendly. This project has many uses, including things like building a Jacob's ladder(a.k.a looking like a mad scientist), an electronic igniter, a welder, a rail gun... Ok maybe not... . But anyway lol, I hope you enjoy! :)

Let's get started!

DISCLAIMER: If you attempt to replicate this project please do so safely! This project deals with dangerous amounts of electricity. The maker assumes all risks related to the manufacturing and usage of this project.

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Step 1: SCIENCE!!!

So anyone who has read any of my instructables knows that I like to do a little bit of explaining about how my projects work. A transformer in its simplest form consists of two coils of copper wire wound around an iron core. The core is made up of many layers of iron plates sandwiched together. The first coil, which takes electrical power from the source, is called the primary winding, and the second coil, which gives the desired output voltage, is known as the secondary winding. If there are more or fewer turns in the second coil, we can make the secondary current and voltage bigger or smaller than the primary current and voltage. If the secondary winding has more wraps then the primary it's a step-up transformer, and vice versa for a step-down transformer. For the sake of time, I am not going to go into the in-depth science of induction, electromagnetic fields, and flux lines.

Step 2: Tools and Materials.

For this project you will need:


1. a microwave oven transformer.

2. some scrap lumber.

3. a 120 volt switch.

4. 12 gauge wire.

5. two 1/2" by 2 1/2" bolts.

6. four washers.

7. two lock washers.

8. two nuts.

9. two wing nuts.

10. assorted screws

11. a power cord(I used some old vacuum cord)


1. soldering iron

2. table-saw or skill-saw(or even a hand-saw.)

3. wire strippers or knife

4. a drill

5. jig saw

Step 3: Wiring.

If you are using a microwave transformer than there should be a total of five wires. There should be two from the primary winding on the bottom, two from the middle, and one coming from the top of the secondary winding, as well as a small ground wire connected to the core on the very top. We only need to worry about the bottom two and the top one. Just go ahead and snip the two from the middle to keep them out of the way. The two wires on the bottom are where you connect the power. The first high-voltage output line is connected to the wire on top of the secondary coil, the second is connect to the core. Be sure to remove any sealer before you attach the wire to the core though. After a quick clean with an angle grinder, I attached mine to the screw holding the transformer to the wooden base.

For convenience I wired a switch to the power cord. So now that you have the transformer wired that's really all there is to the electrical part. Now on to the housing!

Step 4: The Housing.

I used 1/2" chip board to construct the housing box. There is really not a lot to say about it lol. For ease of use I attached the two high-voltage output lines to two terminals made with the 1/2" bolts. That way I can easily attach whatever I need to. It's up to you to build or style the housing however you want.

Step 5: Cooling.

I would strongly recommend adding a cooling fan of some kind! For my purposes, I won't need to have this running for more than a second at a time so I left it out. But if you are building one of these for extended use, definitely add a fan. Transformers can get quite warm!

Step 6: Results!

Gongrats, you have successfully built yourself a multi purpose high-voltage generator. This should produce anywhere from 2,000 to 3,000 volts, depending on the model of the microwave! This was a quick and easy project, and I really enjoyed making it. If you can think of any other crazy and creative uses for this contraption please leave a comment down below! I hope you enjoyed this instructable and I'll see you next time!

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    3 Discussions


    7 weeks ago

    That's a cool project, I would suggest just 2 things. First, put a light sign so you can always know it's On. Second, instead of bolts you should use nuts in the inside of the box, that way you will never make a short circuit by mistake. I will make my own now! :-D


    3 years ago

    You do realize that your safety warning was rendered moot by the pics that had the LP gas tank holding up your "shield." If that High Voltage spark had contacted the tank, you'd have a high powered bomb on your hands.


    Reply 3 years ago

    I appreciate your concern. But the tank is about 4 feet away and I can guaranty the arc wont travel that far. But I will note your comment, and change the cover pic. Thank you for your comment!