Potentiometers: SAQ Solutions

Listed below are the solutions to the SAQ on Potentiometers:

1. B. Resistor
   A potentiometer is a variable resistor whose resistance can be changed based on the type of potentiometer (ex: manually change resistance with a screwdriver, or change with a dial).
2. By the equation R = ρL/A, increasing the length of the conductive material inside the potentiometer through the slider arm increases resistance of a given half of the potentiometer.
3. To create a rheostat, the potentiometer is connected in series with the circuit and pins 1 and 2 are used. To create a voltage divider, the potentiometer is connected in parallel with the circuit and pins 1, 2, and 3 are used.
   A rheostat is mainly used to apply a variable current to an external circuit, while a voltage divider is often used to get a variable output voltage between the two resistors.
4. No. If we want gain to be accurate at -100, we should choose actual resistors. Potentiometers are useful for testing different resistance values or knowing a general threshold. They can be used if resistance movement is intentional. Here, slight variations or inaccuracies in resistance can lead to incorrect gains.