# What Is a Resistor And What Does It Do

Resistors are components which help control the current flow in a circuit. In case there is high resistance, the current available for a voltage is low and vice versa. The mechanism of controlling the current flow is that resistors convert electrical energy into heat. This is done by collision between electrons and ions between resistors when they move current. They are found in every electrical device which is made in this world. It has two terminals through which electricity is passed. It is designed to drop the voltage as current passes from one terminal to the other.

### Instructions

• 1

Functions

Resistorsâ€™ function is to resist flow of electricity which eventually results in drop of voltage. They are usually found in components within electrical networks of almost every circuit. There are three parameters of resistors i.e. resistance which is calculated in ohms, manufacturing tolerance and heat dissipation which is measured in watts.

• 2

Identification

Colour coded rings are used to determine the value of resistors. You might see five rings in many resistors but four-band resistors are most common. These rings might be close or far and the cluster of rings indicate first and second digit. The third ring is the multiplier while the fourth ring is the tolerance of resistor. It is either gold (5 per cent) or silver (10 per cent). The fifth or the last ring refers to the quality of the resistor. Following are the resistor colour codes

Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Violet = 7
Grey = 8
White = 9
In case there is a cluster of rings coloured brown green orange gold and red. It will be read as 15,000 ohms with a tolerance of five per cent.

• 3

Uses

Resistors are used to form heating elements as they are able to convert electrical energy into heat energy. They are the heating elements in iron, heaters, electric stoves, toasters, hair dryers and many other things. Besides this, they are also used to create filaments in light bulbs.

In addition to these, they are placed in series with each other after being voltage dividers. Their purpose is to create voltage from an input which is either fixed or variable.

Resistors are also used in filtering of signals and are used in circuits in TV and radios.