explain me this? Orange box

[Dmichels]

Ok converted the car to EI 20 years ago Same orange box worked fine for years. Start car in garage the other day, and it craps out. I buy a new box install it and run an extra ground strap for good measure. Starts up fine. I touch the transistor to check temp. I get a zap. Not high voltage mabey 90 volts or so. Is this normal?

[ottawamerc]

I may go out on a ledge here but I would think that is not normal, should be a max of 12v there and possibly only 8? It must be generating a charge somehow and also the reason why its quitting on ya

[469 runner]

Perfectly normal.

[JB400]

 Wanna try to touch the chrome one when it's hooked up?  

[Pete in NH]

Hi,

That's perfectly normal. An ignition coil has two windings a primary and secondary, it's the secondary that produces the voltage to fire the plugs. The way a coil works is that when the transisitor in the orange box turns on current flows in the primary winding building up a magnetic field in the coil. When the transistor turns off, the faster the better, this magnetic field collapes and creates a  high voltage in the secondary to fire the plugs. This collaping field also creates a voltage in the primary winding as well and this is what you are feeling on the transisitor case.

[Dmichels]

Thanks guys glad to know this is normal. I just found it strange that the transistor would be "hot" when running.
Dave

[Rolling_Thunder]

You think that's fun?  Grab a magneto...         

[A383Wing]

You think that's fun?  Grab a magneto...         

Yea...those bite hard....also not fun is the "Little White Wire" for the dash lights in a first gen Charger...

those 66-67 guys know what I mean (250v AC @ 250hz)

Bryan