About Voltage
Voltage (electric potential difference) is measured in volts (V), the SI unit. It describes the force that drives electric current through a circuit.
Household current is typically 120 V (US) or 230 V (EU); high-voltage transmission lines operate in the hundreds of kilovolts range.
Pro Tips
Use Ohm's Law (V = I × R) to relate voltage, current, and resistance in a circuit.
Battery voltages: AA cell is 1.5 V, a car battery is 12 V, and EV packs range from 400–800 V.