Below are some of the more common definitions and math to go along with them.

Volt (V)

Volt is the electrical unit of voltage. One volt is the energy of 1 joule that is consumed when electric charge of 1 coulomb flows in the circuit.

1V = 1J / 1C

Ampere (A)

Ampere is the electrical unit of electrical current. It measures the amount of electrical charge that flows in an electrical circuit per 1 second.

1A = 1C / 1s

Ohm (Ω)

Ohm is the electrical unit of resistance.

1Ω = 1V / 1A

Watt (W)

Watt is the electrical unit of electric power. It measures the rate of consumed energy.

1W = 1J / 1s

1W = 1V · 1A

Decibel-milliwatt (dBm)

Decibel-milliwatt or dBm is a unit of electric power, measured with logarithmic scale referenced to 1mW.

10dBm = 10 · log10(10mW / 1mW)

Decibel-Watt (dBW)

Decibel-watt or dBW is a unit of electric power, measured with logarithmic scale referenced to 1W.

10dBW = 10 · log10(10W / 1W)

Farad (F)

Farad is the unit of capacitance. It represents the amount of electric charge in coulombs that is stored per 1 volt.

1F = 1C / 1V

Henry (H)

Henry is the unit of inductance.

1H = 1Wb / 1A

siemens (S)

siemens is the unit of conductance, which is the opposite of resistance.

1S = 1 / 1Ω

Coulomb (C)

Coulomb is the unit of electric charge.

1C = 6.238792×1018 electron charges

Ampere-hour (Ah)

Ampere-hour is a unit of electric charge. One ampere-hour is the electric charge that flow in electrical circuit, when a current of 1 ampere is applied for 1 hour.

1Ah = 1A · 1hour

One ampere-hour is equal to 3600 coulombs.

1Ah = 3600C

Tesla (T)

Tesla is the unit of magnetic field.

1T = 1Wb / 1m2

Weber (Wb)

Weber is the unit of magnetic flux.

1Wb = 1V · 1s

Joule (J)

Joule is the unit of energy.

1J = 1 kg · 1(m / s)2

Kilowatt-hour (kWh)

Kilowatt-hour is a unit of energy.

1kWh = 1kW · 1h = 1000W · 1h

Hertz (Hz)

Hertz is the unit of frequency. It measures the number of cycles per second.

1 Hz = 1 cycles / s

*Special thanks goes out to the guys at RapidTables.com for putting this together*