Instructables

Flyback driver, 555 timer and other transformer from wall wart. What transistor??

Hello people! 

I recently got my hands on a flyback transformer (that is, I finally got over it and got it out of the monitor :p ) And I want to make a flyback driver. I already have a normal wall wart hooked up backward.

I was thinking that I could connect the wall wart to the flyback and create massive sparks. Could I directly solder the flyback and the other transformer together? If so, what transistor would you advise to use in my 555 circuit in front of the first, normal transformer?

A IRFP460 MOSFET will work when driving flybacks.

I am a bit confused about what you are trying to accomplish but keep in mind a flyback needs to be driven with 10-50kHz.
dunnos (author)  The MadScientist2 years ago
I have 2 transformers, one from a flyback and one from an old wall wart. I want to drive the wall wart one with my 555 and hook up the output to the flyback. Will that work?
No the voltage will be too high.

To drive a flyback with a 555 you need to use high frequency pulsed DC see this

When you run pulsed DC at say 12V, through an inductor (transformer primary) you will get a voltage spike every DC pulse at 200-500V so stepping up with a transformer really isn't necessary. (The flyback wouldn't take the voltage even if you got it to work)

Remember it needs to be driven with 10-50kHz.
dunnos (author)  The MadScientist2 years ago
Okay thank you, that's pretty much what I wanted to know, you get best answer :)

I have this little transformer from an old disposable camera... tried putting pulsed 5vdc on that and it didn't work. What happens when a transformer is overvolted?
When the transformer is 'overvolted' the insulation on the secondary windings will break down and the transformer will short out.

Sometimes if you just tap the primary leads on a transformers primary the voltage can discharge back into the battery (generally not dangerous) this may have happened with you little transformer. To resolve this you need to run the electricity through the MOSFET I suggested or one much similar.
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!