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Old 02-17-2013, 07:00 PM   #18
MikeK
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Join Date: May 2010
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Default Re: Bad Condenser Symptoms?

Quote:
Originally Posted by Wilbur View Post
. . . Can anyone explain to me what the condenser does?
The ignition coil is a high ratio transformer. Transformers do not work on straight DC. The magnetic field must be moving to induce electrons to move in the windings.

When the points open the ignition coil magnetic field collapses (moves) and induces an electro-motive force (voltage) in the primary as well as the secondary coil. It's not very much in the primary coil because there are only a few windings in the primary, but it's enough, maybe up to 200V, to jump a small air-gap such as the one between the barely open points. That tiny spark is enough to erode metal away from the points and you'll burn up the points in a matter of minutes. The condenser (capacitor) is an electron reservoir and prevents the points from arcing by absorbing the induced primary voltage rather than letting it arc wildly across the open points.

If you have a solid state (transistor) switch instead of mechanical points there is no air-gap to ionize and maintain an arc, so no condenser is necessary. Example: Pertronix "ignitor" modification. Of course, that mod has it's own set of problems!
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