GATE Electrical Engineering - Complete Master Library

 

GATE Electrical – Analog Electronics

Practice Problems – Page 12

This section contains practice problems based on Inverting Operational Amplifier circuits.

---

Problem 111

Question:

An inverting amplifier has Rf = 10 kΩ and Rin = 2 kΩ. Find voltage gain.

Solution:

Av = −Rf / Rin

Av = −10000 / 2000

Av = −5

---

Problem 112

Question:

If input voltage is 0.5 V and gain is −10, find output voltage.

Solution:

Vo = Av × Vin

Vo = −10 × 0.5 = −5 V

---

Problem 113

Question:

What is the input impedance of an inverting amplifier?

Answer:

Input impedance ≈ Rin.

---

Problem 114

Question:

If Rin = 5 kΩ and Rf = 25 kΩ, calculate voltage gain.

Solution:

Av = −Rf / Rin

Av = −25k / 5k = −5

---

Problem 115

Question:

Why is the inverting input terminal called virtual ground?

Answer:

Because voltage at the inverting terminal is approximately zero due to negative feedback.

---

Problem 116

Question:

What is phase shift of an inverting amplifier?

Answer:

180°

---

Problem 117

Question:

If Rf = Rin, what is voltage gain?

Answer:

Av = −1

---

Problem 118

Question:

Which op-amp circuit performs signal inversion?

Answer:

Inverting amplifier

---

Problem 119

Question:

What happens if feedback resistor increases?

Answer:

Voltage gain increases.

---

Problem 120

Question:

What is the main advantage of negative feedback in op-amp?

Answer:

It stabilizes gain and reduces distortion.