Electrical Quantities & Ohm's Law
study the basic electrical quantities used in electrical work, including voltage, current, resistance, and power.
Ohm's Law explains the relationship between voltage, current, and resistance and is one of the most important calculations used by electricians.
Voltage
Voltage is the electrical pressure that pushes current through a circuit. Voltage is measured in volts (V).
Current
Current is the flow of electrical charge through a circuit. Current is measured in amperes (A).
Resistance
Resistance opposes the flow of current. Resistance is measured in ohms (Ω).
Power
Electrical power is the rate at which electrical energy is used. Power is measured in watts (W).
Ohm's Law can be used to calculate voltage, current, or resistance when the other two values are known.
V = I × R
Where:
V = Voltage
I = Current
R = Resistance