Flyback Transformer Drivers





Introduction: Flyback Transformer Drivers

About: I am a total nerd who works as a software developer, and knows a bit about computer/software technology. Plus I like space and vintage computers.

This instructable is the seventh one that I made. This instructable is about how to make a fly back transformer driver. There are two that I will show, one that is mechanical, and one that is solid-state (for the more technologically advanced). My inspiration for this instructable was that I made a mechanical driver, then it died; so I bought another one but decided to make a solid-state one.

Warning: this instructable deals with high voltage, so you could get shocked and potentially killed. I take no responsibility for any damage, injury, or death.

P.S.  The picture you see on this page is copied and pasted from Google, so it's not this good or high power.

Step 1: Parts for Simple Driver

These are the parts that you need for a simple fly back driver. The pros are that it's simple to build and lasts a long time. The cons are that it doesn't make as big sparks as solid-state drivers, and it's very noisy.

1- 5 volt relay
?- wires
1- 6 volt power source
1- fly back transformer with pins identified
1- on/off switch (optional)

1- soldering iron
1- solder wire
1- helping hands station (optional)

Step 2: Schematic for Simple Driver

This is the schematic for the simple driver. Just wire the relay like the picture has it. The two wires sticking on the bottom is what you connect to the power source and transformer. Just follow schematic #2 to see how to connect it all.

Step 3: Parts for Solid State Flyback Driver

These are the parts that you need for the solid state driver. The pros are that it makes bigger sparks. The cons are that it's harder to make.

1- 6 volt power source
1- on/off switch (optional)
1- fly back transformer with pins identified
1-555 timer ic
1-power transistor (see schematic and text file)
1-0.01 uf capacitor
?-resistors (it depends on whether you use the schematic or my info in the text document)
?- wires

1- soldering iron
1- solder wire
1- helping hands station (optional)



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    The first one is very retro but I will try it first.

    Have you tried the simple driver does it work and if it does at what frequency I want to replicate please help

    7 replies

    The simple driver runs at a relatively low frequency, probably under 100 Hz.

    It really depends on the size of your relay, bigger relays run slower than smaller relays.

    Technically no because it isn't near the resonant frequency of the flyback, but actually yes (more like kind of) because you'll still be able to draw sparks from it, just they will be smaller and less powerful.

    How many cm or mm sparks can I expect from the relay and the 555 timer

    Depends on the input voltage/current/frequency.

    It's possible, you should probably use some kind of diode for protection.

    I have actually burned 555 chips from shorting out the output of the flyback.

    Sorry, but how on earth do you expect that relay driver to work? What oscillates the relay? As far as I can see, you have both ends of the coil wired in series between the power source and the transformer. I wired it up just for kicks, it turns the relay on and that's about it.

    1 reply

    Sometimes that happens, not sure why. In my tests I used a 5 volt relay, those tiny ones that RadioShack used to sell. It works by the relay turning on and swinging the contact which shorts out the coil causing the contact to fall back but opens the circuit and drawing the contact back, over and over.

    see what happens if you add a film capacitor across the +V and the positive end of the flyback. i did this with a very similar circuit with a ignition coil and it gave me much better output (from <1mm sparks to 20 mm long sparks)

    3 replies

    Do you mean in series with the flyback transformer?

    In parallel. That way you make a L1 tank circuit. It has to be well tuned so first without it figure out how many turns gives you the most output, then start adding various film or MKP capacitors to see what works best.

    That wasn't exactly my original idea but it will do exactly the same thing.

    Hmm... Yeah, I saw this configuration on the ZVS circuit.

    I might give it a try but people don't want me to play with high voltage...

    But it's so much fun... :( I guess I'll have to go with second best and watch photonicinduction's videos. :)

    Does the capacitor have to be a 0.01uf or can it be bigger?

    1 reply

    for the solid state one, it could be different, but the frequency would change.

    Would any old power transistor work? I've taken apart quite a few power supplies form things lately and have a couple dozen transistors/MOSFETs that are attached to heatsinks.