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Overview
Voltage is the difference in electric potential between two points. It tells how much energy per unit charge is available or required as charge moves between those points. Voltage is central to batteries, outlets, circuits, electronics, power systems, and electrical safety.
Potential Difference
Voltage is not usually a property of a single isolated point. It is a difference between two points. A battery creates a voltage between its terminals.
Energy per Charge
Voltage measures energy per unit charge. A higher voltage means more energy is transferred for each unit of charge moving through a device or circuit element.
Voltage Sources
Batteries, generators, solar cells, and power supplies can maintain voltage differences. These sources separate charge or convert other forms of energy into electrical energy.
Voltage and Current
Voltage can drive current through a complete conducting path. The amount of current depends on voltage and the resistance or impedance of the circuit.
Voltage Drop
A voltage drop occurs across a circuit element when electrical energy is transferred to that element, often becoming heat, light, motion, or stored energy.
Measuring Voltage
A voltmeter measures potential difference between two points. It is connected in parallel with the circuit element or points being measured.
Voltage and Safety
High voltage can be dangerous because it can drive harmful current through the body if a conducting path exists. Electrical safety depends on voltage, current, resistance, contact conditions, and duration.
Common Mistakes
A common mistake is saying voltage flows. Current flows; voltage is a potential difference that can drive current.
Why This Matters in Physics
Voltage links electric fields, energy, charge, circuits, batteries, power supplies, electronics, and electrical safety.