Electrical Units

Unit		Notes
Volt	V	Measure of potential difference
Ampere	A	Measure of current flow
Watt	W	Unit of power: 1 volt supplying one ampere
Coulomb	C	Unit of charge: 1 ampere flowing for 1 second. Mostly used for scientific purposes - the day-to-day measure, used for example in determining the charge available from a battery, is the Ampere-hour (Ah) or milliAmpere-hour (mAh).
Ohm		Measure of resistance or impedance
Farad	F	Measure of capacitance
Henry	H	Measure of inductance
Mho		Measure of conduction: Reciprocal ohm = 1/ohms (rarely used)

In an electrical circuit the current (I) flowing through the circuit depends upon the voltage applied to it (V) and the resistance of the circuit (R):

I =	V
	R

The Power in the circuit (P) is the product of the voltage and the current:

P = V * I