# Robotics Basics: Resistors

# Resistors:

Resistors are this tiny electronic components that you'll see in almost everything. They are extremely important. And today, you are going to learn about them.

## What do they do? :

Think of drinking a drink with a straw. Now if you were to slightly apply pressure on the straw by pinching it; the flow of the drink into your mouth would decrease. This is exactly what a resistor does.

With the resistor we can **limit the flow of electricity.** Every **electronic component** requires a specific amount of voltage and current. If the limit is exceeded then the component is damaged. There is **possibility of damage** to the other components as well. The risk of causing an explosion or a fire also exists. For this reason we use resistors to **reduce the voltage and maintain the current** supplied to an electrical component.

## How to find out the required resistance:

To find out the required resistance of an electrical component Ohm's law is required. **According to Ohm's law:
R=V/I (R = Resistance; V = Supplied Voltage - Voltage Drop; I = Current; )**

Required Voltage = ( Supplied Voltage - Voltage Drop ) / Current

The resistance is denoted by Ohm

A typical red LED has a voltage drop of **1.8 Volt and current requirement of 25 mA (0.025 A)**. If we supply 5 Volt electricity then the required resistance will be **(( 5 - 1.8 ) / 0.025) = 128 Ohm**.

Since, 128 Ohm resistors are hard to find, **220 Ohm resistor is used instead**. (Using a smaller value resistor is risky.)