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Carbon Pile:
A resistance device used to impose a drain on a battery to allow measurement as it would be when starting a vehicle.
Circuit:
A circuit complete loop. An electrical circuit is when a battery is connected from the positive terminal by wires into one terminal of the device and a return wire is connected from the other terminal and back to the negative terminal of the battery. An open circuit is when a switch is opened to stop the electricity flow or when a wire is disconnected or when the device fails (globe blows) all these things will stop the device from working.
Distributor:
An ignition distributor is a cylindrical object, about the size of a can of beans, with rubber covered wires as thick as a pencil sticking out from the engine, the wires are connected to the spark plugs. It distributes the electricity to each spark plug in the correct order. Care must be taken when reaching near the distributor with the ignition switched on, as high voltage electricity will travel to vehicle earth via the shortest path.
Electrode:
A bare metalic object connected to an electrical charge, of which a spark may jump from. An electrode can also be suspended in a liquid to make a chemical change in the liquid.
Electrolyte:
Electrolyte is a fluid, when electrolyte is mentioned in relation to a car battery it is a made up of a solution of (36%)Suphuric Acid and (64%)Distilled Water. Topping-up the electrolyte is adding distilled water, not tap water.
Gassing:
A term used when charging a battery and hydrogen gas is being released from the electrolyte.
Hydrometer:
Hydrometer is a syringe with a calibrated float inside it which accurately measures, by comparison the 'weight or density' of electrolyte with that of water. Water has a Specific Gravity of 1.000 Suphuric Acid has a Specific Gravity of 1.835. By sucking a quantity of solution into the hydrometer, the float raises by the amount of density of the fluid, which can be read from the fluid line against the scale attached to the float. As density is affected by temperature, a quality hydrometer has a scale for temperature correction. Batteries must be checked at 26.7'C for each 5'C above that add 0.004 to the hydrometer. For each 5'C below 26.7'C subtract 0.004 from the hydrometer reading.
Insulator:
As the name suggests is insulates and separates an object from other objects avoiding an electrical short circuit. Insulators can be made of plastic, rubber, laquer paints, wood, air, almost anything that won't easily conduct electricity. Even the best insulators aren't compleat insulators, given enough electricity, electrons will flow using the atoms that make up the material or air to find a pathway to connect and balance the circuit.
High Tension Leads:
A carbon centre covered with an insulating rubber outer sheath. These are commonly called spark plug leads and carry high voltages usually in between 10,000 and 70,000 volts. The carbon centre acts as a radio and electrical noise filter which supresses the magnetic field and stop it travelling into nearby wires.
Open circuit:
An open circuit is when the electrical path is interupted, when you switch off a device it causes an open circuit, interupting the flow of electricity. If a wire connection comes apart it is an open circuit, if a device fails it may be an open circuit.
Pre-Ignition:
When a piece of sharp glowing piece metal or glowing ember of carbon lights the fuel mixture before it is time to it is called pre-ignition. Pre-Ignition does not nessecerily do damage to the engine apart from giving poor performance for the fuel used, but there can be a flow-on effect from Pre-igntiion. It can cause two fires to light in the combustion chamber. With the two fires aproaching eachother from different directions, the mixture trapped between them is squeezed between them quickly building heat and pressure until it detonates. Pinging is an often used term to describe an engine rattle when accellerating. The term "pinging" is often confused between Pre-Ignition and Detonation. Pre-Ignition will cause a loss of performance as the pressure rise that does the work is mistimed. Detonation is an severe impact taken inside the cylinder, more like an explosion than a controlled burning of gases.
Short Circuit:
A short circuit is when a track is cut across a loop, making a smaller loop inside the original loop. As the negative battery terminal of a vehicle is connected to the car body an electrical short circuit is when the electrical wiring insulation is rubbed through on a part of the body allowing the wire to touch the car body and the electricity travels in a shorter circuit. If this happens along the wire after it has left the device, the device will remain on, however if the wire grounds before the device the battery will connect straight to ground it may cause a fire, just like a toaster element glows, the wire will glow melting the plastic insulation along it's length and feed the fire. Generally an electrical fire will travel along the wiring until reaching back to the battery. The fire can also start other short circuits starting more fires, unless the battery can be disconnected quickly, those fires may well burn the entire vehicle.
Specific Gravity:
Water has a Specific Gravity of 1.000 Suphuric Acid has a Specific Gravity of 1.835. By sucking a quantity of solution into the hydrometer, the float raises by the amount of density of the fluid, which can be read from the fluid line against the scale attached to the float. As density is affected by temperature, a quality hydrometer has a scale for temperature correction. Batteries must be checked at 26.7'C for each 5'C above that add 0.004 to the hydrometer. For each 5'C below 26.7'C subtract 0.004 from the hydrometer reading.
Voltmeter:
A device used to measure voltages, such devices are either single or multiple readout meters. a single unit would be a simple "Volt Meter". A multiple readout meter in commonly called a "Multi Meter"
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