Potentiometer Working
Potentiometer
also known as pot is generally used in circuits to provide variable
resistance or variable voltage. The heart of the potentiometer is a
resistive strip inside it through which one can adjust the amount of
resistance/voltage to pass in a circuit through it. Potentiometers are
commonly used in circuits for various purposes like to control volume in
audio circuits, to regulate the speed of the motor in a fan, as light
dimmer, etc.
A potentiometer is shown in the images below.
You can see there are three terminals on the potentiometer which are used to connect it to any external circuit.
The metal cap in the above image forms the outer covering and encloses all parts of the potentiometer.
The metal bearing shown in the left side of the above image is used for mechanical connections.
You
can see two concentric circles in the image above. The outer black arc
(resistive strip) on the plate is the heart of the potentiometer. It is
used to provide variable resistance to the circuit. The inner circle
made up of a conductive material is connected to the middle terminal.
As
shown in the figure, the brush, generally made up of stainless steel
has two sections of dents. First one with three dents moves on the
resistive strip and second one with two dents moves on the inner circle
which is connected to the middle terminal (wiper).
The
brush is attached to the shaft. It moves on the plate and the
resistance applied to the circuit, depends on the position of the brush
on the plate.
When
we rotate the external shaft, the position of the brush varies
accordingly. The resistance applied in a circuit depends on the position
of the brush. The brush is designed so as to connect the resistive
strip to the middle terminal via inner conductive circular metal plate
which in turn is connected to the middle terminal of potentiometer at
every instant.
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