Basic Electrical Units


Test your knowledge

Before starting the chapter, let’s see how much you know!


When the free electrons move from atom to atom of a conductor or semiconductor, they typically bounce around randomly. Once a voltage is applied to the material, the electrons move from the negative towards the positive.

Remember that electrons have a negative charge. Since the negative side of the voltage source repels the electrons, they move away from it and head towards the positive side, which they are attracted to.

Current, in electrical terms, is the rate of the flow of charge. The current in a conductor is measured by the amount of charge (number of electrons) that flows past a certain point in a unit of time:

I =Q / t

An ampere, or amp, is the unit for current. This is symbolized by A.

The short video below does an excellent job of explaining current and voltage.



Current and Voltage video by Matrix Education is under a Creative Commons Attribution License.


Icon for the Creative Commons Attribution 4.0 International License

Basic Electricity Copyright © 2019 by Chad Flinn is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

Share This Book