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Question
State the uses of a potentiometer.
Solution 1
The applications of the potentiometer discussed above are used in a laboratory. Some practical applications of the potentiometer are given below.
- Voltage divider: The potentiometer can be used as a voltage divider to change the output voltage of a voltage supply.
- Audio control: Sliding potentiometers are commonly used in modem low-power audio systems as audio control devices. Both sliding (faders) and rotary potentiometers (knobs) are regularly used for frequency attenuation, loudness control and for controlling different characteristics of audio signals.
- Potentiometer as a sensor: lf the slider of the potentiometer is connected to the moving part of a machine, it can work as a motion sensor. A small displacement of the moving part causes a change in potential which is further amplified using an amplifier circuit. The potential difference is calibrated in terms of displacement of the moving part.
- To measure the emf (for this, the emf of the standard cell and potential gradient must be known).
- To compare the emfs of two cells.
- To determine a cell's internal resistance.
Solution 2
a. Potentiometer as a voltage Divider:
1. The potentiometer can be used as a voltage divider to continuously change the output voltage of a voltage supply. 
2. As shown in the above figure, potential V is set up between points A and B of a potentiometer wire.
3. One end of a device is connected to positive point A and the other end is connected to a slider that can move along wire AB.
4. The voltage V gets divided in the proportion of lengths l1 and l2, such that
V1 = `("dV"("l"))/("dL")` and
V2 = `("dV"("L" - "l"_1))/("dL")`
b. Potentiometer as an audio control:
1. Sliding potentiometers are commonly used in modern low-power audio systems as audio control devices.
2. Both sliding (faders) and rotary potentiometers (knobs) are regularly used for frequency attenuation, loudness control, and for controlling different characteristics of audio signals.
c. Potentiometer as a sensor:
1. If the slider of a potentiometer is connected to the moving part of a machine, it can work as a motion sensor.
2. A small displacement of the moving part causes changes in potential which is further amplified using an amplifier circuit.
3. The potential difference is calibrated in terms of the displacement of the moving part.
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