Question

In the circuit given below, the value of RL for which it absorbs maximum power is ___________

(a) \(\frac{400}{3}\) Ω

(b) \(\frac{2}{9}\) kΩ

(c) 350.38 Ω

(d) \(\frac{4}{9}\) kΩ

I got this question in an internship interview.

The doubt is from Advanced Problems on Millman’s Theorem and Maximum Power Transfer Theorem topic in division Useful Theorems in Circuit Analysis of Network Theory

Answer 1

The correct choice is (c) 350.38 Ω

Explanation: 5 = 200I – 50 × 2I

Or, I = \(\frac{5}{100}\) = 0.05 A

VOC = 100 × 3I + 200 × I = 25 V

V1 = \(\frac{\frac{5}{50}}{\frac{1}{50} + \frac{1}{200} + \frac{1}{100}} \)

= \(\frac{0.1}{0.02+0.005+0.01} \)

= 2.85 V

I = \(\frac{2.85}{100}\) = 0.0142 A = 14.2 mA

ISC = \(\frac{2.85}{100}\) + 3 × 0.0142 = 0.07135 A

∴ RTH = \(\frac{V_{OC}}{I_{SC}}  = \frac{25}{0.07135}\) = 350.38 Ω.