# Robotics Basics: Resistors

in #robotics3 years ago (edited)

# 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.)