What is Resistor, Symbol, Types, Resistor Color Coding

A resistor is an electronic component. The work of a resistor is to resist the flow of electricity. This flow of electricity is called current. In other words, the resistor stops the overflow of electricity. Every resistor has values that tell how resists current flow. This resistance value is called ohm. The resistance is used in the electronics circuit and also used in the printed circuit boards. The main work of the resistor is stopping the overflow of current in the circuit. This is called a resistor.

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Symbol of a Resistor

Types of Resistor

There are different types of resistors but will explain the main types of resistors.

Variable Resistor

The variable resistor is able to have its electrical resistance adjusted. The variable resistor is used in electrical circuits because variable resistors help to control voltage and current. The main work of variable resistors deal with voltages and currents that are a part of the circuit. The variable resistors are mostly used in electric circuits to adjust the value of current and voltage. Variable resistors adjust the value of voltages by changing the resistances and keeping the current constant.

Variable Resistor
Variable Resistor

Working of Variable Resistor

The variable resistor is a resistor of which the electric resistance value can be adjusted. A fixed resistor has a resistance that does not change. The symbol shows the variable resistor that varies the value of voltage and does not change the value of voltages. The variable resistors adjust the value of current in the electric circuit. In a circuit, the variable resistors connect with voltage and current.

This is the circuit diagram of a variable resistor.

circuit diagram of a variable resistor

Uses of variable resistor

Variable resistors are mostly used for electric circuits to regulate the value of current and voltages.

Different types of variable resistor

  • Potentiometer
  • Rheostat
  • Thermistor

Linear Resistor

The linear resistor’s resistance does not vary with the flow of current through it. When we applied voltages in the circuit so the current always be proportional to the voltages applied across it. Linear resistors are classified into two types.

  • Fixed resistor
  • Variable resistor.

This circuit diagram of the linear resistor.

circuit diagram of the linear resistor
circuit diagram of the linear resistor

Working of Linear Resistor

The linear resistor absorbs the electrical energy in the process where it acts as a hindrance to the flow of electricity by reducing the voltage. The electronic circuits the heat dissipation is typically a fraction of a watt. In the words, the linear resistor work according to the circuit. In the diagram voltage through current flows in the whole circuit.

Use of Linear Resistors

The linear resistors use in tuning and calibration the circuit. Today, the usage of rheostats was replaced by electronic switching. The rheostats have lower efficiency.

Non- linear Resistor

The non-linear resistor works as the voltages and current characteristics vary non-linearly. The value of current and voltages vary depending on other factors such as light and temperature, but they may not be linear.

Working of non-linear resistor

Non-linear resistors work because the electrical current flowing through them changes with the exchanges in applied voltages or temperature and does not change according to ohm’s law. In the words, the non-linear resistors are working according to ohm’s law.

This circuit diagram of a non-linear resistor.

Uses of non-linear resistor

The non-linear resistor is used for protecting the device from over-voltage conditions. Non-linear resistors are used for measurement and control purposes. The non-linear resistor used for the resistance decrease as the temperature increase.

non-linear resistor
non-linear resistor

Series Resistor

Series resistors are connected back to back in a single line. In the circuit, the series resistor is also connected in a single line. The current will equal flow through all the resistors. Resistors in series are said to have a common current. In other words, the current will be same in the all points which are connected in a single line.

This is a diagram of a series resistors.

diagram of a series resistors
diagram of a series resistors


The diagram shows all the resistor joints in a single line. Two or more resistors will connect in series when the same amount of current flows through all the resistors. In the circuit, when the connected voltage and resistors are also connected in series that circuit works so current flows the same all the connected resistors. If any resistor is broken or a fault occurs, then the entire circuit is turned off.

Uses of Series Resistors

Series resistors are mainly used in low-power-based circuits. Series resistors are used in voltage divider circuits. The series circuit connections are frequently used in electrical equipment.

Parallel resistor

Two resistors are joined between the same two nodes, they are in parallel. Resistors connected in parallel have the same voltages drop but the currents flowing through these resistors are not necessarily the same. In the electrical, parallel resistors do not always look like two parallel lines.

This is a diagram of a parallel resistor.

diagram of a parallel resistor
diagram of a parallel resistor


In the parallel circuit, two or more paths for the current to flow through simply remember that parallel means two paths up to thousands of paths. The flow of electricity is divided between each according to the resistance along each route. When branches meet at a common point, the current branches out and recombined. When resistors are joined in parallel circuits more current flows from the source than would flow for any of them individually and the total resistance is lower.

Uses of parallel Resistor

The use of a parallel resistor in every home electrical wiring can be done in parallel circuit form. Parallel circuits are used for computer hardware design. Parallel resistors are used in the dc power supply of the automobile industry.

Resistors Color Coding

The four-band color code is the most common variation. Resistors have two bands for the resistance value, one multiplier, and one tolerance band. The diagram shows the four bands are brown, red, green, and orange.

This is a diagram of color coding resistors.

Resistors Color Coding
Resistors Color Coding

Uses of color code resistor

Color code uses in broadcast products. If color code is mentioned on the component easily identify its value and function. I mentioned resistor symbols, their types, uses, and color-coding resistors.

Who invented Resistor Color Coding?

The resistor colour code was invented in the 1920s by the Radio Manufacturers Association (RMA)

Also, Read What is Diode?

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