An ignition coil (an aa cried a spark coil) is an induction coil in an automobile's ignition seestem that transforms the battery's law voltage tae the thousands o volts needed tae creaut an electric spark in the spark plugs tae ignite the fuel. Some coils hae an internal resistor, while others rely on a resistor wire or an external resistor tae leemit the current flowing intae the coil frae the car's 12-volt supply. The wire that goes frae the ignition coil tae the distributor an the heich voltage wires that go frae the distributor tae each o the spark plugs are cried spark plug wires or heich tension leads. Oreeginally, every ignition coil seestem required mechanical contact breaker pynts an a capacitor (condenser). Mair recent electronic ignition seestems uise a power transistor tae provide pulses tae the ignition coil. A modren passenger automobile mey uise ane ignition coil for each ingine cylinder (or pair o cylinders), eliminating fault-prone spark plug cables an a distributor tae route the heich voltage pulses. Ignition seestems are nae required for diesel ingines which rely on compression tae ignite the fuel/air mixture.