# Electrical Definitions

Here is a list of electrical definitions…

Charge – is the positive or negative quality that causes things to experience force when in the presence of other charged objects.  It has to do with the ratio of protons to electrons.  The Coulomb is the SI quantity for measuring charge.  It is equal to the charge transferred in one second across a conductor.

Electric Potential Difference – is a difference in electric potential energy between two points.  It is the amount of energy needed to move a charged particle from one position to another.  Measured in Volts.

Current – is the flow of electric charge or electrons within a system.  It occurs when there is a difference in electric potential energy across a conductor.  The SI unit for measuring current is the ampere.

Resistance – the property of a conductor which resists the flow of current through it or the opposite of conduction.  For many materials voltage and current are directly proportional to each other, while resistance and conductance are constants.  This relationship is called Ohn’s law.  Resistance = voltage / current or conductance = current / voltage. An ohm is the SI unit for electrical resistance.

Power – is the amount of energy consumed or converted in a unit of time.  Power is measured in Watts, so the higher the wattage, the more power is used.  1 Watt is equivalent to 1 Joule/second.

Energy – is a measure of the capacity of a system to do work.  It is the work a system does in changing with respect to a reference point or starting point.  Energy is expressed in Joules.

Inductance – is a property of a conductor in which a change in current creates a voltage.  Self inductance is when a voltage is created within the conductor itself, and mutual inductance is when a voltage is created in nearby conductors as well. Inductors, or coils of wire are used to concentrate the magnetic field.  The Henry is the SI unit for inductance.

Capacitance – is the ability to store electrical charge.  Capacitors are used to do so.  The Farad is the SI unit for measuring Capacitance. Farad = Joules / Voltage squared.