Re: Beginer building a small sstc.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

"I don't think modern ignition coils quite work like that.
The old "T-Model" coils had their own points/capacitor
and were essentially an induction coil that functioned
quite well with a 6 or 12 volt DC input. However, a modern
ignition coil is essentially an impulse transformer that re-
quires a pulsed input of several hundred volts amplitude to operate
properly, which is provided externally by the ignition
control module. A simple 12 volt DC input will not not yield a usable
high voltage output from an ignition coil."

	Modern ignition coils are perfectly happy working from a 12 volt input,
provided the drive circuit is correct.  The switching connects the
primary across the 12 volts for a time duration which allows current to
build up to a suitable value, then opens the circuit and the "inductive
kick" provides a high pulse of voltage which is coupled to the
secondar.  Timing and repetition rate can be controlled independently.
Lots of drive circuit designs available.

	The simple capacitor-light dimmer arrangement also works well and is
sure a lot simpler.  Of course, it draws huge current spikes out of the
power line............

Ed