question_answer

The arm PQ can revolve with uniform speed continuously about P round the circular uniform potentiometer track\[X-Y-Z\]. The voltage between RS will vary with respect to time

A)  Sinusoid ally    

B)         Linearly

C)  Rectangular

D)         Like saw tooth  

Correct Answer: D

Solution :

 The equivalent circuit similar to that of the standard potentiometer configuration can be drawn as below: Point is at zero potential of point\[Z\]is equal to that of the positive terminal of the battery. As the arm \[PQ\]goes from \[X\]to\[Z\], the potential difference between the point\[R\]and\[S\]goes on decreasing linearly. The potential difference becomes zero when the wiper arm is at point\[Z\]. Then the wiper rotating clockwise comes in contact with point\[X\]. So, the potential difference instantaneously becomes maximum. This repeats itself as shown below: This wave form is like teeth of a hand saw.