H

HALF-WAVE - A pulsating DC produced by rectifying AC.


HALL-EFFECT - The "Hall Effect" is a process where current is passed through a small slice of semi-conductor material at the same time as a magnetic field to produce a small voltage in the semi-conductor.


HARD SOLDER - Uniting two pieces of metal with material having a melting point higher than "soft" solder. Example: silver soldering.

HAZARD WARNING SYSTEM - Electrical switching device and associated lights (usually the front and rear turn-signal lights) producing flashes of light to indicate that a car is in a distress situation. Also called "emergency flashers" or "fourway flashers".

HEAT RANGE - A classification for spark plugs. The higher the number, the "hotter" the plug runs, which means that the plug does not dissipate heat as quickly as a "cooler" plug does.

HEAT SINK - Metal bracket in end frame of alternator that contains and absorbs heat from diodes.

HIGH TENSION - Secondary or induced high voltage electrical current. Circuit includes wiring from ignition distributor cap to coil and to each spark plug.

HIGH TENSION SECONDARY VOLTAGE - Voltage which enables current to jump the spark plug gap. This voltage is caused by the collapse of the magnetic field around the coil secondary windings.

HOLE - A moveable vacancy which acts as a positive charge in a semi-conductor.

HORN RELAY - Electromagnetic circuit-closing device that switches electricity to the horn when the horn button is depressed.

HOT LEAD - A wire, or conductor, in the hot or power circuit.

HYDROMETER - An instrument used to measure the specific gravity of liquids. Hydrometers can be calibrated to indicate the charge level of a battery or the percentage of antifreeze in a coolant mixture.