When the primary turns of the Ignition Coil are powered with the 12 Volts DC (13.8V to 14.4V) it is at a Current level of several amperes.
The Current is permitted to flow by the control circuitry until the magnetic field energy in the core of the coil is at a maximum.
Then the Primary Current is disrupted which allows the magnetic field that has been built up to collapse very rapidly.
It is the high rate of speed of the magnetic field collapse that induces a very high voltage into the Secondary Turns of the Ignition Coil which is able to produce a brief spark of several tens of milliamperes of current.
The Instantaneous Power of the spark can indeed be very high for a few microseconds. All of the Electrical Energy that had been pumped into the coil as a low voltage current in the Primary is suddenly released in a very short time as a High Voltage Low Current pulse in the Secondary.
It's approximately the same amount of energy, minus losses of the coil's copper, but it's compressed in time into a high energy burst.
Over the long term, the average power is quite low.Statistics: Posted by SeaMonkey — Wed Aug 15, 2007 4:50 pm
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