A coil is a step up transformer. It takes low system voltage 12 to 14.5VDC and provides an igniting spark to the spark plug 50,000 + volts. The Element uses a coil over plug system which means the each spark plug has its own "coil pack" which plugs directly on to the spark plug, eliminating the need for spark plug high voltage wires. The coil pack has two windings , primary and secondary. Primary winding is low voltage, low resistance and high amperage. the secondary winding is high voltage,high resistance and low amperage. The PCM (power control module, aka computer) provides a timed pulse of electricity to the primary winding which induces a corresponding high voltage surge in the secondary winding sufficient to jump the gap of the spark plug,the arc is exposed to the compressed fuel air mixture in the cylinder, and we have ignition.