Types of Resistors

We already know that resistor is an electrical component which controls the flow of current. In this post, you’ll learn different types of resistors.

Linear resistors

Linear resistors exhibit a direct relationship between current and voltage. i.e the current increases when the voltage increases and current decreases when the voltage decreases. In simple words, they obey the Ohm’s law.

Fixed linear resistors

They have a fixed value which can’t be changed:
  1. Carbon composition resistors: These are simple resistors which are often found in our labs. Their value of resistance is indicated by rounded colored bands. The ratio of insulation material determines the actual resistance they possess. They are available in values 1 ohm to 25 mega ohms.
  2. Wire wound resistors: They contain an insulation core around resistor wire which is made of tunsten or manganin. They are usually rated at 2 watt to 100 watts and are available from 1 kohms to 200 kohms.
  3. Thin film resistors: They contain a thin film around the conduction material.

Variable linear resistors

They possess a variable value of resistance.

  1. Potentiometer: It is three terminal device which has rotating knob over its body and can be used to obtain a variable voltage.
  2. Rheostat: It is used to control the current flow through the circuit.
  3. Trimmers: They are modern potentiometers. A screwdriver is used to rotate their knobs for obtaining a variable output.

Nonlinear resistors

  1. Thermistor: A two-terminal device whose resistance changes with the change in temperature
  2. Varistors: A resistor which is used to protect circuit from voltage spikes.
  3. Photoresistor: Its resistance changes with the intensity of light.
Let’s watch this video to visually understand the construction and working of resistors.

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