GROL Amplifier and Oscillator Circuits 2

Question 1

In a Colpitts oscillator, the frequency-determining tank circuit consists of:

Accepted Answer

Two capacitors and one inductor

Answer

Two inductors and one capacitor

Answer

One capacitor and two resistors

Answer

Three resistors in a ladder network

Question 2

What distinguishes a Hartley oscillator from a Colpitts oscillator?

Accepted Answer

A Hartley oscillator uses a tapped inductor in its tank circuit

Answer

A Hartley oscillator uses two capacitors in its tank circuit

Answer

A Hartley oscillator requires a crystal for frequency stability

Answer

A Hartley oscillator uses only resistors and capacitors

Question 3

Why are crystal-controlled oscillators preferred in commercial radio transmitters?

Accepted Answer

They provide superior frequency stability compared to LC oscillators

Answer

They generate higher output power than LC oscillators

Answer

They require no external power supply

Answer

They automatically adjust to changing channel conditions

Question 4

The Barkhausen criterion states that for sustained oscillation, the total loop gain must be:

Accepted Answer

Equal to unity with a total phase shift of 0° or 360°

Answer

Greater than unity with exactly 90° of phase shift

Answer

Less than unity with any phase shift

Answer

Equal to zero

Question 5

Which oscillator circuit is commonly used with a quartz crystal because it requires only one active device and connects the crystal directly in the feedback path?

Accepted Answer

Pierce oscillator

Answer

Colpitts oscillator

Answer

Hartley oscillator

Answer

Clapp oscillator

Question 6

In a three-section RC phase-shift oscillator, what is the total phase shift contributed by the RC ladder network?

Accepted Answer

180°

Answer

90°

Answer

270°

Answer

360°

Question 7

A Clapp oscillator improves on the Colpitts design primarily by:

Accepted Answer

Adding a series capacitor with the inductor to reduce the effect of transistor capacitance variations

Answer

Replacing the transistor with a vacuum tube for higher stability

Answer

Using a crystal as the primary frequency element

Answer

Eliminating the need for a feedback network