Ohm's law

 Educational level: this is a secondary education resource.
 Educational level: this is a tertiary (university) resource.

Based on the work of Georg Simon Ohm, Ohm's law is one of three fundamental laws which begin the study of electronics, in partnership with Kirchhoff's Voltage Law and Kirchhoff's Current Law, laws. These three laws form the frame on which the rest of electronics is constructed. It's important to note that these laws don't apply everywhere, but definitely apply with great precision in wires, which are used to connect most electronic parts together in a circuit. Though individual parts may or may not be analysed by Ohm's law, their relationship to the circuit can be. Any student completing a course in electronics should be capable of quoting Ohm's law in his or her sleep. Not because they learn it once, but because it's used repeatedly in conjunction with almost every other task in electronics.

The Ohm's law

Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.

${\displaystyle V=IR}$

In the electrical circuit,there are three factors

Current,denoted by I
Potential difference, denoted by V
Resistance,denoted by R.
${\displaystyle I={\frac {V}{R}}\;\;\;\;\;\;\;or\;\;\;\;\;\;\;V=I\cdot R}$

Example:

If you have one amp (1A) of current flowing through a 2 ohm resistor, how much voltage will be across it?
 2 volt Correct, I=1, R=2, I*R=V, 1*2=2 1 volts Try again, using ohm`s law 1/2 a volt Try again, did you switch current and voltage? 3 volts Try again, do not add them together, use I*R=V