# Electrical Current

### After reading this section you will be able to do the following:

• Explain how an electrical current is produced.
• Describe how electrical current is quantified and measured.

Electricity is a term used to describe the energy produced (usually to perform work) when electrons are caused to directionally (not randomly) flow from atom to atom. In fact, the day-to-day products that we all benefit from, rely on the movement of electrons. This movement of free electrons between atoms is called electrical current. Current is typically designated as I in circuits. When current flow is controlled it can be used to do useful work. Electricity can be very dangerous and it is important to know how to work with it safely.

## Amperage

It is very important to have a way to measure and quantify the flow of electrical current. The flow of electrons is measured in units called amperes or amps (A) for short. An amp is the amount of electrical current that exists when a number of electrons, having one coulomb of charge, move past a given point in one second. As a reminder, a coulomb is the charge carried by 6.25 x 10^18 electrons. 6.25 x 10^18 is scientific notation for 6,250,000,000,000,000,000. Since we cannot count this fast and we cannot even see the electrons, we need an instrument to measure the flow of electrons. An ammeter or a multimeter is used to indicate how many amps of current are flowing in an electrical circuit.

### Review

1. Electricity is a word used to describe the directional flow of electrons between atoms.
2. The directional movement of electrons between atoms is called electrical current.
3. Amperage is a term used to describe the number of electrons moving past a fixed point in a conductor in one second.
4. Current is measured in units called amperes or amps.