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Q & A: Variable resistors

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Most recent answer: 01/29/2012
HOW variable resistor is adjucted in circuit? why variable resistor has three terminals?
- zubair farooq (age 20)
The three-terminal variable resistor is also known as the potentiometer. Here is a nice diagram of the potentiometer:

If only two terminals are used (the middle one and either A or B), the potentiometer acts as a usual variable resistor. Since the resistance of a linear resistive material is proportional to its length, turning the knob and changes the resistance.

The potentiometer serves as a voltage divider when all three terminals are used. The output voltage across the middle lead and either A or B can be adjusted while the voltage across A and B remains the same.

- Tsung

(published on 01/29/2012)

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