# Numerical - Average dc output voltage of a chopper with ON time of 20ms and OFF time of 15 ms

## What will be the average dc output voltage of a chopper which is supplied by 500 V dc with ON time of 20ms and OFF time of 15 ms ?

**Options:**

a. 150 V

b. 230 V

c. 285 V

d. 325 V

Correct Answer: c. 285 V

**Explanation:**

According to given data,

T_{ON} = 20 ms = 20 x 10 ^{-3} s

T_{OFF} = 15 ms = 15 x 10 ^{-3} s

T = T_{ON} + T_{OFF}

T = (20 x 10 ^{-3} + 15 x 10 ^{-3} ) = 35 x 10^{-3} s

Therefore, duty cycle of the chopper is given by,

T = T_{ON} / T = 20 x 10 ^{-3} / 35 x 10^{-3} = 0.57

Thus, average dc output voltage of chopper can be evaluated by,

V_{L} = V_{dc} x duty cycle = 500 x 0.57 = 285 V