Driver circuit and transistor equivalent?

[things]

Hey,

I am going to build this circuit. The transformer is a flyback transformer from a old CRT monitor. Now I have added audio modulation to this circuit, and according to a few people it should work, but i'd like to get a few more opinions.

Also, my local electronics store (Jaycar) doesn't have the BD243C, so I need to find an equivalent. I have tried the TIP41C, but since the transformer creates inductive feedback it clamps.

**broken link removed**

Any opinions?

Cheers,
Dan

 

[Chippie]

Where's the circuit?

What supply are you running it off, the transistor breakdown voltage may be too low....transformers like this are generally driven with a proprietry HV switching device, bjt or mosfet...

 

[things]

Bah I always forget to do that, I get too lost in my writing

I have a 0-16V @ 25A bench PSU here I can power it from.

EDIT: I do have the HV transistor from the monitor the flyback came from, however I can't find ANY data on it, so I can't figure out if it's suitable or not. It's a Panasonic C5914 3D3

 

[Chippie]

There's no snubber network across the transformer primary...your transistor wil have a short existance....

 

[things]

I found a datasheet for the transistor used in the monitor! **broken link removed**

This thing seems to have some pretty large ratings, maybe it would stand all the abuse

As for the snubber, what do you recommend, keeping it as simple and cheap as possible?

Cheers.
Dan

 

[marcbarker]

Hey! That circuit looks like great fun!! I want one!

I think it's worth blowing up some transistors along the way in the process of finding one to survive long enough. I'd be inclined to use just about any old power transistor you can find, strip them out of any switching PSUs, TVs or even try a 2n3055 for a few seconds of potentially lethally dangerous HV fun.

For a snubber, you could maybe use a low-energy light bulb minus the inductive ballast, that way you know the circuit is running and use the power for good theatrical use.

Is this for a Tesla coil ? The Tesla Geeks are really into this kinda thing.

 

[things]

Hey, It's for a flyback. The circuit was originally made for driving a flyback at a constant frequency, though with a minor addition I put there it means you can audio modulate it. The sound quality isn't great, but hey, it's cool either way

You can also use it for solid state tesla coils (SSTC's).

OK, I have decided to go with one of these **broken link removed**

I use them in my anti-parallel ignition coil setup, and it hasnt died yet desipte over 5 years of abuse. Aslong as they can switch fast enough (>20Khz) I guess i'm sorted