# What are amps, watts, volts and ohms?

Amps, watts, volts and ohms are units of measurement in a similar way that the metre is a unit for distance. The ampere (often shortened to amp) is the unit of electric current. The symbol for amps is A. Current is a measurement of how much charge is moving through a particular point in a unit of time. One amp is the current generated when 6.242 x 1018 electrons pass a particular point per second. That’s 6,242 followed by 15 zeros – a lot of electrons! Watts are a measurement of electrical power. The symbol for the watt is W and one watt = one joule per second (joule is the unit of energy). So a 60W light bulb converts 60 joules of electrical energy to heat and light energy every second!
Volts are the unit of measurement for voltage. Voltage is a measurement of electrical potential energy per unit charge and one volt is equivalent to one joule per coulomb (coulomb is the unit of charge).
When current flows through something, it’ll experience resistance. This is measured in ohms. Some materials like wood have a high resistance which means little current can flow through. Other materials like copper have a low resistance and conduct electricity well.