Question

An alternating voltage V = 150 sin(314)t is supplied to a device which offers a resistance of 20 Ω in forward direction of electric current while preventing the flow of electric current in reverse direction. The form factor is ___________

(a) 0.57

(b) 0.318

(c) 1.414

(d) 1.57

The question was posed to me during an interview.

This is a very interesting question from Advanced Problems on Millman’s Theorem and Maximum Power Transfer Theorem topic in portion Useful Theorems in Circuit Analysis of Network Theory

Answer 1

The correct option is (d) 1.57

For explanation I would say: From the voltage equation, we can get Vm = 150 V and Im = 150 / 20 = 7 A

RMS value of the current, Irms = Im / 2 = 7/2 = 3.5 A

Average value of the current, Iavg = Im / π = 2.228 A

Form factor = Irms / Iavg = 3.5 / 2.228 = 1.57.