Flyback Transformer Driver With 555 Timer

In this instructable I will show you how to run an old CRT flyback.

These things can output from 5KV to 50KV of pure power so be careful with them.

I am not responsible to any damage to your equipment and components.

To assemble this project you need a few easy to get components.

Mandatory Components:

1. Flyback transformer (the one I used is a HR 80202)

2. NE555 timer

3. IRFZ44N or IRFZ46N mosfet

4. 200 ohm or 220 ohm resistor

5. 1uf 26V to 100uf 26V electrolytic capacitor (the lower the value the faster the mosfet switches)

6. Breadboard or pcb

7. 2x 1N4007 Diodes

8. 12V Battery (The one I used is a multipower 12V 7,2AH lead-acid)

Optional Components:

1. LED (blue is preferred) paired with a 1K resistor)

2. Heatsink for mosfet (for long runs)

3. 2 wire screw terminal (to easily change the coil)

4. A 3.3uf 2000V-10000V high voltage capacitor (for nice loud sparks)

That's all you really need for this project.

This circuit is pretty easy to assemble and works pretty well (for me atleast).

The flyback has 20 turns of primary (any scrap wire will do).

The circuit works by making the mosfet turn on and off very fast with the help of the 555 timer, the capacitance of the capacitor (on pin 2 of NE555 and ground) decides the switching speed. The lower the capacitance the faster it switches (you can a variable capacitor instead of the one shown to find the perfect speed for you).

If you need any help understanding the circuit, make a comment.

After you have built your driver and wound your primary on the flyback you are ready to test.

Please double check all connections before powering up the circuit to avoid frying anything.

Apply 12V DC to the power terminals (if you connect it backwards the diode should save you from frying your timer).

How do I locate the 2nd pin of the secondary?

- Take the high voltage wire and try touching every single terminal at the bottom of the flyback to find the one (the one with the biggest spark is the one).

Want even scarier sparks without a voltage doubler or marx generator?

Add a 3.3uf 2000V-10000V Ceramic capacitor to the output and make a spark gap (mine jumps from around a centimeter on a fully charged battery).

This should give you louder sparks.

Why should I use a heatsink?

- The mosfet gets really hot really fast (I fried 2 within 20 seconds of continuous runtime without a heatsink).

You have reached the end of this instructable. If you made the project for yourself please share it with us by clicking the "I made it!" button below.

I will use this driver circuit in some other instructables!

If you have any questions make a comment