The GATE Grind

GATE 2021 IN – Question 40

Analog Electronics · Operational amplifiers and applications · 2 marks · Multiple choice

The ideal OPAMP has output $V_o=5$ V. The value of $R_L$ in the shown circuit is ______ k$\Omega$.

Diagram for GATE 2021 IN question 40
  1. 2.5
  2. 5
  3. 25
  4. 50

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Show answer and explanation

Correct answer: (C) 25

Explanation

The equal 10-kΩ divider at the inverting input gives V−=Vo/2=2.5 V, so V+=2.5 V. KCL at V+ gives (2.5−1)/10k+(2.5−5)/10k+2.5/RL=0.

Hence 2.5/RL=0.1 mA and RL=**25 kΩ, C**.