On Mon, 20 Feb 2006 16:30:49 +0000, Andy Hall
wrote:

On Mon, 20 Feb 2006 16:21:41 +0000, Grunff wrote:

MikeW wrote:

and something to interrupt the
primary.

This is the bit I need the help with ;-(

A DPDT relay. Use one pole to get the relay to click on/off (by
connecting the coil in series with the n/c), and the other pole to
switch your primary. You'll need to put a large-ish capacitor across the
relay coil to slow down the clicking, once every couple of seconds is
about right.


Something to prevent pitting and destruction of the relay contacts?

Condenser from a points based ignition system should be fine. You
could probably also find the relay in the scrap yard along with the
coil and battery.

I wonder about the RFI aspects of all of this as well. Do commercial
units have relays or semiconductor switching, I wonder?

Old ones were relays..new ones semiconductor.

In theory it won't cause any more interference than a car ignition
system as it uses the same parts.

sponix