Let's Make Robots!

Flyback Transformer Driver

I took a flyback transformer from a crt monitor and built the driver here - http://tacashi.tripod.com/elctrncs/555sstc/555sstc.htm

I am running the circuit at 19V with a power supply rated for 3A, but I cannot get the HV line to arc.  I even hooked it up to a multimeter and found that I wasn't getting any voltage at all.  I have tested the circuit, and it is fine.  I have even tried winding my own primary coil around the core (used internal and my custom wound primary) , but I still can't get any power from the HV line.

Any reccomendations?  I would like to stick with a simple 555 driver.

 

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Just a couple observations:

Flyback transformers are part of a tuned circuit and operate best at their resonate frequency. If the flyback is out of a television, that frequency is 15,750 hertz. I don't know why the author is running his at 27.000 hertz.

I don't see a damper diode accross the output transistor and I don't believe this transistor has one integral. This will help speed the collapse of the field and protect your output transistor.

Lastly, it looks like the duty cycle on his 555 circuit has way too much "on" time, it should be a narrow spike, his duty cycle looks to be near 50%.