GATE Electrical Engineering - Complete Master Library

 

GATE Electrical – Analog Electronics

Practice Problems – Page 19

This section contains mixed problems from Diodes, Transistors, Operational Amplifiers, Filters and Oscillators.

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Problem 181

Question:

What is the cut-in voltage of a silicon diode?

Answer:

≈ 0.7 V

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Problem 182

Question:

What is the cut-in voltage of a germanium diode?

Answer:

≈ 0.3 V

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Problem 183

Question:

If β = 100 and base current is 40 μA, find collector current.

Solution:

Ic = β × Ib

Ic = 100 × 40 μA = 4 mA

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Problem 184

Question:

What is the ripple factor of a full wave rectifier?

Answer:

0.482

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Problem 185

Question:

What is the efficiency of a full wave rectifier?

Answer:

81.2%

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Problem 186

Question:

If op-amp gain = 20 and input voltage = 0.2 V, find output voltage.

Solution:

Vo = Av × Vin

Vo = 20 × 0.2 = 4 V

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Problem 187

Question:

What is the slope of first order filter?

Answer:

−20 dB/decade

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Problem 188

Question:

What is the slope of second order filter?

Answer:

−40 dB/decade

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Problem 189

Question:

Which oscillator uses positive feedback?

Answer:

All oscillator circuits use positive feedback.

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Problem 190

Question:

What is the ideal CMRR of an op-amp?

Answer:

Infinite