Resist is the word which means “to oppose”. Resistance is the property of opposing the flow of electrons, in a conductor or a semiconductor. A Resistor is an electronic component which has the property of resistance.

Symbol and Units

The symbol for a Resistor is as shown below.

The units of resistance is Ohms, which is indicated by Ω (omega).

The formula for resistance is

R = V/I

Where V is Voltage and I is Current. It would really be difficult to manufacture the resistors with each and every value. Hence, few values are chosen and the resistors of such values are only manufactured. These are called as “Preferred Values”. In practice, the resistors with near values are chosen to match the required applications. This is how a practical resistor looks like −