Stored Electricity: Voltage and Volts ($V$)

Stored electricity is called voltage and is measured in volts. More precisely, voltage is the difference in electric potential energy between two points.

One volt is equal to 1 joule ($J$, see physics) per 1 coulomb ($C$), or $V = \frac{J}{C}$. A coulomb is a quantity of electrical charge (i.e. electrons or protons). Volts can also be expressed in terms of watts and amps: $V=W/A$.

Another way to put it is, a volt is the amount of electricity required to accelerate 1kg by 1 meter per second squared (a joule) for 1 second (resulting in a displacement of $1m$), divided by the quantity of electrical charges (coulombs). In other words, a volt is "how much work can be done per coulomb".

Voltage can be derived by Ohm's Law as $V = IR$.

Common Voltages

Video: Voltage (Khan Academy)

History

Volts and voltage are both named after Alessandro Volta, who invented the first battery in 1800.

Deeper Knowledge on Voltage and Volts

Conductance and Siemens

The ability to conduct to current, measured in siemens

Resistance and Ohms

Opposition to current, measured in ohms

Watt's Law (Power Law)

A formula to define the relationship between power, voltage, and current (P=IV)

Ohm's Law

A formula for determining voltage, current, and resistance

Broader Topics Related to Voltage and Volts

Charge and Coulombs

How force is exerted in electromagnetic field, measured in coulombs

International System of Units (SI)

Formal terms and definitions of the metric system

Electrical Engineering

Build and deconstruct electrically powered devices

Electricity

Energy that results from charged particles