[Prev][Next][Index][Thread]
Re: DC TC
Hi ignition coil coilers,
To add to this note, here are some ideas I
used on my i.c. powered TC:
> I can call my model-t coil project DC as that is what it operates
> on. The best output I got was 3 inches. I was thinking of a way to put
> it all in a self contained unit but I have been using my CP apacitor so
> space is out of the question there until I find a different cap. I will
> eventually have pics to this project on my homepage. I recently took
> a model-t coil apart all the way down to 'BUT NOT' depotting it. Ha!
> there is a cap in there! I was using the output to charge a cap, break
> a spark gap and run to a TC. I found the natural 'buzz' of the model-t
> coil to be arounf 500hz. I have been messing around with the thought
> of making a coil setup that may grab some strange harmonics and use
> the model-t coil output directly into a primary instead of the external
> cap, gap setup. The only disadvantages I see to this are current and
> windings for around 500hz. A really big coil!
>
> Bob Schumann
I used a single transistor to switch a 12V supply to the
primary of the ignition coil (i.c.). The oscillator was made using a
dual TTL monostable integrated circuit. I could adjust i.c. break rate
and dwell with this circuit.
The primary cap for the TC was about 3nF from memory. I used a
break rate for the i.c. of around 50Hz. Beyond that, the coil
couldn't supply enough energy to charge that cap up to full voltage.
You can tailor the TC primary cap size to suit the break rate (and
adjust Tesla primary inductance for TC tune). Faster break means less
energy stored in the i.c. core which needs a smaller TC cap to keep
TC primary voltage up. Or you can use less TC primary inductance and
run at the lower voltage.
The TC ran at about 1.5MHz. It was closewound on a varnished
cardboard tube. At its best, it gave 6" streamers but these were
pretty faint and needed to be viewed in the dark. Solid sparks were
shorter at about 3".
Malcolm