A flow of electrons forced into motion by voltage is known as current. The atoms in good conductors such as copper wire have one or more free electrons of the outer ring constantly flying off. Electrons from other nearby atoms fill in the holes. There are billions of electrons moving aimlessly in all directions, all the time in conductors

# CURRENT

### What is current?

A flow of electrons forced into motion by voltage is known as current. The atoms in good conductors such as copper wire have one or more free electrons of the outer ring constantly flying off. Electrons from other nearby atoms fill in the holes. There are billions of electrons moving aimlessly in all directions, all the time in conductors.

When an emf (voltage) is impressed across a conductor it drives these free electrons away from the negative force toward the positive. This action takes place at near the speed of light, 300,000,000 metres per second although individual electrons do not move far they have a shunting effect. This is similar to a number of cars pulled up at traffic lights when the last vehicle fails to stop and hits the second last vehicle which in turn hits the third last vehicle...............

The amount of current in a circuit is measured in amperes (amps). Smaller units used in electronics are milli-amps mA (1 / 1,000th of an ampere) and micro-amps uA (1 / 1,000,000th of an ampere). An ampere is the number of electrons going past a certain point in one second.

The quantity of electrons used in determining an ampere is called "coulomb" which one ampere is one coulomb per second. A coulomb is 6,280,000,000,000,000,000 or 6.28 X 10 18 electrons.

This (a coulomb) is the unit of measuring electrical quantity or charge.

### RELATED TOPICS ON CURRENT

electron theory

voltage

ohms law

resistance

resistor colour code chart

Want to create a page link to me from your site? It couldn't be easier. No HTML knowledge required; even the technophobes can do it. All you need to do is copy and paste, the following code. All links are greatly appreciated; I sincerely thank you for your support.

Copy and paste the following code for a text link:

```<a href="https://www.electronics-tutorials.com/basics/current.htm" target="_top">visit Ian Purdie VK2TIP's "Current" Page</a>```

and it should appear like this:
visit Ian Purdie VK2TIP's "Current" Page

the author Ian C. Purdie, VK2TIP of www.electronics-tutorials.com asserts the moral right to be identified as the author of this web site and all contents herein. Copyright © 2000 - 2001, all rights reserved. See copying and links. These electronic tutorials are provided for individual private use and the author assumes no liability whatsoever for the application, use, misuse, of any of these projects or electronics tutorials that may result in the direct or indirect damage or loss that comes from these projects or tutorials. All materials are provided for free private and public use.
Commercial use prohibited without prior written permission from www.electronics-tutorials.com.