Question

Find rms value of output voltage of a 220 V input Type A chopper for a duty ratio of 0.25, assuming a voltage drop of 2 V across the chopper when it is on.

• A. 109 V
• B. 110 V
• C. 55 V
• D. 54.5 V

Hint:

RMS output of a chopper: \( V_{\text{rms}} = V \sqrt{D} \), where \( V \) is effective ON voltage.

Answer 1

The Correct Option is A

Effective voltage when the chopper is ON = \( V = 220 - 2 = 218 \, \text{V} \) Duty ratio \( D = 0.25 \) The rms output voltage of a Type A chopper is: \[ V_{\text{rms}} = V \sqrt{D} = 218 \times \sqrt{0.25} = 218 \times 0.5 = 109 \, \text{V} \]