GX200 clone Ignition Voltage

[Jasn]

Yo!

I recently acquired an oscilloscope for pretty cheap, and was gonna hook it up to the ignition coil on my clone just to see what it'd be like. The input says it is rated to 400V peak to peak. Obviously an ignition coil will be producing higher than this, is there any way to still view it? Could I use Voltage division with some resistors? Would this still preserve the signal for analysis?

 

[mckutzy]

Im curious.... why?....

 

[Whitetrashrocker]

I wouldn't.

Spark plugs are in the 10k plus voltages.

Even with a 10x probe....

 

[itsid]

No no noooo
you never want to tap into a high voltage coil directly.

Instead make a wire wrap "sensor" (it's exactly as it sounds)
get some copper wire, wrap it around the ignition cable a few times and then....
tap into that with your oscilloscope!
(you should get a mV reading with the exact pulse of the coil)

Bonus: you can read while the engine is running

'sid

 

[Jasn]

Why not is kinda what I was thinking!

I wasn't planning on hooking it straight up at all, so don't worry.

Just a couple of coils of any insulated wire should work around where exactly would be the best place?

 

[itsid]

doesn't make a difference really,
closer to the coil or closer to the spark plug is just the same.

what you are basically creating is a very small (very low efficiency) transformator,
the coil picks up the magnetic field created by the electrical discharge in the ignition cable coming from the coil of course;
and thus a small voltage and current is induced which then can be picked up by your oscilloscope.

Since the electromagnetic field strength in your ignition cable is constant
(too short, too high voltage to see a noteworthy drop)
it doesn't matter where you wrap your wire windings.

'sid

 

[Bbqjoe]

Sid and I had a long discussion, and it was determined that the best course of action is NOT to use yourself as any part of the circuit coming off of the coil at any time or place.

 

[Jasn]

Yep that all makes sense, sorry I just didn't see the part of your first comment saying to throw it around the coil and wasn't thinking. Also, if I knew how many turns was on the ignition coil (primary) would that give me the voltage that the coil was running at?

 

[itsid]

the coil is running at 6.5V
(I know you meant the output voltage.. but you haven't said so )
it's 22kV IIRC, but why do you wanna know exactly (it's of no importance really the voltage is only to pass the high resistance ignition cable and plug (~15kOhms together) and the airgap on the plug.
if it's 22 or 25kV or even 30 or just 17kV doesn't make any difference really.

'sid