Glossary of technical terms

Amperage: This is a name sometimes used in place of current. It is used because the electrical current is measured in Amperes (Amps). By definition, 1 Ampere = the current that will cause silver to be deposited at a rate of 0.001118 grams per second when passed through a solution of silver nitrate.

Charge: The electric charge of an object is a measure of how much electricity is there. It is similar to the mass of an object when you are dealing with gravity, but unlike mass charge can be either positive (+) or negative (-). At the atomic level charge is measured in multiples of the charge on an electron (-1), in larger cases the usual measurement is the Coulomb.

Conductor: A conductor is a material that allows electricity to move through it easily. That is, it is a material with low electrical resistance, one in which a fairly small voltage will produce a fairly large current. The opposite of an insulator.

Coulomb: The Coulomb is the unit normally used to measure large charges. 1 Coulomb = the amount of electricity passing a given point in 1 second at a current of 1 Ampere.

Current: The electrical current is simply a measure of how much electricity passes a given point in a fixed amount of time. It is similar to the current of a stream or river, which measures how much water passes a given point in a fixed amount of time. Electrical current is measured in Amperes (Amps)

Electric Field: The space near a charged BODY where other charges are affected. Similar to the gravitational field near a planet, except that it can also repel. The term is also used to describe how the field will affect other charges (which way and how much it will accelerate them).

Faraday Cage: The name given to a device that shields its inside from electric fields generated by static electricity. Usually a complete conductive shell, it collects stray charges and, because like charges repel, stores them on the outside surface (where they can be further apart than on the inside). The electric fields generated by these charges then cancel each other out on the inside of the cage. Often used to protect sensitive radio equipment.

Frequency: For an alternating current, the frequency is the number of times that the current goes through a complete cycle per second. It is measured in Hertz (cycles per second).

Ground: The ground is an arbitrarily decided point whose voltage is taken as zero. In many situations, equipment is connected physically to the actual, dirt ground, so that voltage is taken as zero--hence the name. In England the term "earth" is used, for the same reason. To be "grounded" means to be connected to a place that is maintained at the ground voltage.

Induction: Induction is the process by which charge is moved in a conductor by the presence of an electric field. In wires this will lead to a current, in discrete conducting objects it will lead to local charging--ie. the side near the inducing charge will become the opposite charge and the far side will acquire a similar charge leaving the overall charge of the object unchanged.

Insulator: An insulator is a material that electricity has a hard time moving through, if it can at all. For a true insulator it takes a very high voltage to produce any current at all, and that often results in damage to the insulator. The opposite of a conductor.

Resistance: Electrical resistance is a measure of how hard it is for a current to pass through a given material. It is similar to the way that it is harder for you to walk through water than air. It is usually measured in Ohms.

Static Electricity: Static electricity (or just "static") is the name used to cover those phenomena that involve charges that are not moving (much)--ie. they are static. The other form of electrical phenomena is current electricity, where the charges are moving in a large-scale, organized way.

Transformer: A transformer is simple a device that transforms electricity form one voltage to another. The power coming out of the transformer cannot exceed that going in, so the output current is reduced in direct proportion to the gain in voltage.

Voltage: Voltage is a measure of the force on a unit charge at a given point in space due to all the other "local" charges. It is similar to the gravitational pull on a unit mass in space, except that, since charges can be + and -, the force can be attractive or repulsive. 1 Volt = force required to produce a current of 1 Ampere in a wire of 1 Ohm resistance.