Resistor is a passive component which resists the flow of electric current. Resistance is the property of resistor by which it opposes the flow of electric current.
💡Table of Contents
- About Carbon composition resistor
- About Wire wound resistor
- About Metal film or carbon film resistor
What is Variable resistor or adjustable resistor ?
Types of Resistor
Resistors are classified into two types :
- Fixed resistor
- Variable resistor or adjustable resistor
Fixed resistor
Fixed resistor have fixed or constant resistance value .The
fixed resistor is the most common resistor.
The circuit symbol of fixed resistor is :
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| Circuit symbol of fixed resistor |
Types of fixed resistor
The fixed resistor further classified as
1. Carbon composition resistor
2. Wire wound resistor
3. Metal film resistor or carbon film resistor.
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| Types of Resistor |
1. Carbon composition resistor
It's resistive part is made up of carbon dust or graphite
and a non conducting ceramic or clay powder mixture.
The value of resistance of resistor depends upon the ratio
of carbon to ceramic ( conductor to insulator ).
If the value of a above ratio is high in a resistor than its
resistive resistance value is low. If the value of above ratio is low in a
resistor then its resistance value is high .
The mixture is moulded into cylindrical shape with metal
wire.
Carbon composition resistor is very cheap and widely used
component .
2. Wire wound resistor
Wire wound resistor is made of winding a wire around an
insulating cylindrical core of ceramic.
Usually wire of materials such as conductor nichrome or
magnin are used which have high resistivity.
Wire wound resistor have more accuracy than carbon
composition material.
3. Metal film or carbon film resistor
Its resistive part is made up of resistive material like
pure carbon or some metal.
Generally oxide material used for film material.
The resistive value of resistor is controlled by increasing
the desired thickness of film.
Metal film resistor have a much better temperature stability
than carbon composition resistor.
Variable resistor
Variable resistor are resistors whose resistance can be
changed between 0 to a certain maximum value.
They usually have three leaders, two fixed and one movable
lead. They are commonly used as volume control and in Voltage Regulator.