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GATE 2019 EE – Question 44

Analog and Digital Electronics · Operational amplifiers: characteristics and applications · 2 marks · Multiple choice

In the circuit below, the operational amplifier is ideal. If $V_1=10$ mV and $V_2=50$ mV, the output voltage ($V_{out}$) is

Diagram for GATE 2019 EE question 44
  1. 100 mV
  2. 400 mV
  3. 500 mV
  4. 600 mV

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Correct answer: (B) 400 mV

Explanation

This is a difference amplifier with equal ratios $\frac{100\text{ k}}{10\text{ k}}=10$, so $V_{out}=10(V_2-V_1)=10\times40\text{ mV}=400$ mV.