Perry Mick wrote:

Attached is a schematic of the coils.  Still some mystery there,
we don't know exactly what's in those igniter modules.  But
it's basically just a TTL input trigger to a power transistor
output.  They get a lot of money for something that's probably
a very simple circuit inside.

On the trailing, the input ST is the trigger, on the leading
GT is the trigger.  On the trailing, CI is a toggle input, makes
the igniter pulse alternate coils.  One coil fires on the first
ST, the other coil on the next ST.

--
Perry J. Mick
Duckt N7XR
http://www.ductedfan.com

Chuck wrote:

I took one of those modules apart. (It was a bad one, from trailing
igniter.) It is filled with gooey gel to stabilize the wiring in the unit.
The gel does not come off, or I would take a pix. It looks like a thick film
hybrid construction, with some surface mount components. The driver is a NPN
transistor, a very substantial looking die with leads going to the main
board. My guess is that the resistor is to limit the peak current thru the
transistors to about 30 amps. The leading coil primary seems to be a
slightly lower resistance than the trailing coil, which might explain why
there is a resistor only on the leading coil.

Chuck Dunlap

 
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