In this lesson, you will learn the Ohm’s law, which is the formula of electronics that you will find everywhere.

The Ohm’s law

The below is a simple resistor circuit with a battery.

$V$ is voltage in Volt (V). $I$ is current in Ampere (A). $R$ is resistor value in Ohm (ohm).

$V = I \times R$ $R = { V \over I }$ $I = { V \over R }$

When the current is 1 A, and the resistor is 2 ohm, the voltage is;

$V = I \times R = 1 A \times 2 ohm = 2 (V)$

When the voltage is 5 V, and the current is 500 mA (0.5 A), the resistor is:

$R = { V \over I } = { 5V \over 500 mA } = 10 (ohm)$

When the voltage is 5 V, and the resistor is 2 ohm, the current is;

$I = { V \over R } = { 5 V \over 2 ohm } = 2.5 (A)$

Power equation

Power is an amount of work. For example, a 1,000 W fan does two times more work than 500 W fan, i.e. it makes more flow of wind.

$P (W) = V \times I = ( I \times R ) \times I = I^2 \times R$

Other lessons

Other lessons in Electronics Basic Course: