Sparks to ignite the fuel mixture are created by either a spark plug or a device called an ignitor. When a spark plug is used, the spark was generated by either a magneto or else a trembler (or 'buzz') coil. A buzz coil uses battery power to generate a continuous series of high voltage pulses that are fed to the spark plug. For igniter ignition, either a battery and coil is used or a "low tension" magneto is used. With battery and coil ignition, a battery is wired in series with a wire coil and the igniter contacts. When the contacts of the ignitor are closed (the contacts reside inside the combustion chamber), electricity flows through the circuit. When the contacts are opened by the timing mechanism, a spark is generated across the contacts, which ignite the mixture. When a low tension magneto (really a low-voltage high-current generator) is used, the output of the magneto is fed directly to the igniter points and the spark is generated as with a battery and coil.