Whipper Snipper Project :)

[Terry_Sare at Dell.com]

I used a 2n3055 back in 1981 to convert my 68 bird to electronic ign. Works
but get a large heat sink, a diode to clamp the collector to ground. Remove
the ballast resister from the +12V line and hook 12V directly to + on coil.
Connect collector to - lead, connect cathode of diode (1n4005 or something
like that) to the - lead. connect the emitter and anode to ground. Your  PC
LPT outputs 5 volts, connect the base (through resister) to PC, however may
not drive the 2n3055 hard enough without toasting LPT port. Need to put a
2n2222 driver in line cause hfe on 2N3055 is very low. Go search Web for
hooking up things to LPT port -- like servo motors -- that will show you how
to boost output voltages and isolate your PC from the nasty thing that go
bang. IGBT are better but can be little harder to get hold of, like not at
radio shack or local electronic supply store. 2n3055 is good to 20Khz or
better -- you won't reach that even with a two stroke.

Isolate your PC from this stuff!!!!!!!!! REALLY. Don't want to replace that
PC. 

Terry

-----Original Message-----
From: Wes Branchflower [mailto:hemi_265 at hotmail.com]
<snipped>

I have a 2N3055 PNP transistor, which is rated at being able to switch 
15AMPS.

Is this all I need to switch the coil? Is it that simple? Are there special 
automotive grade transistors for this purpose?
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