# Analog Circuits Questions and Answers – Hartley Oscillator-1

This set of Analog Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Hartley Oscillator-1”.

1. Recommended frequency range of Harley oscillator is __________
a) 30KHz-30MHz
b) 1KHz-10MHz
c) 2Hz-3MHz
d) 0.5KHz-40MHz

Explanation: Recommended frequency range of the Hartley oscillator is 30KHz-30MHz. Frequencies higher or lower than this range will cause distortion.

2. Lower frequencies are not practically possible in the case of Harley oscillator because of the requirement of low ___________ value.
a) Capacitance
b) Resistance
c) Inductance
d) Gain

Explanation: Lower frequencies are theoretically possible in Hartley oscillator however in practice, the achievement of required inductive value is a problem.

3. Which type of feedback is used by Hartley oscillator?
a) Voltage series feedback
b) Current series feedback
c) Voltage shunt feedback
d) Current shunt feedback

Explanation: The feedback used in Hartley oscillator is Voltage series feedback.

4. Which component of Hartley oscillator is used in the feedback system?
a) Inductor
b) Resistor
c) Capacitor
d) Transistor

Explanation: Center tapped inductors are used in Hartley oscillator to ensure feedback. These are often in parallel to a variable capacitor, and feedback is sent into the base of the transistor.

5. Which of the following network is used to give feedback to transistor of Hartley oscillator?
a) Inductive fixed bias
b) Capacitive fixed bias
c) Inductive voltage divider
d) Capacitive voltage divider

Explanation: Inductive voltage divider bias is used, wherein a center tapped inductor in parallel to a capacitor is in the feedback network to the base of the transistor/amplifying element.

6. How many capacitors are there in the tank circuit of Hartley oscillator?
a) 1
b) 2
c) 3
d) 0

Explanation: There is only one capacitor is used in the tank circuit of Hartley oscillator.

7. How many inductors are there in the tank circuit of Hartley oscillator?
a) 1
b) 2
c) 3
d) 0

Explanation: There are two inductors in the tank circuit and one capacitor, in the Hartley oscillator. Often though, we use a center tapped inductor instead of two inductors.

8. The frequency of Hartley oscillator is expressed as __________
(Where L is effective inductance and C is the capacitance)
a) 1/(4ᴨ√LC)
b) 1/(2ᴨ√LC)
c) 1/(3ᴨ√LC)
d) √3/(2ᴨ√LC)

Explanation: Frequency of Hartley oscillator can be expressed as 1/(2ᴨ√LC). L is the total cumulatively coupled mutual inductance if two separate coils are used with mutual inductance M. Frequency of oscillation can be adjusted by varying the tuning capacitor C or the inductance.

9. Active element used in Hartley oscillator is __________
a) Cell
b) Voltage regulator
c) Diode
d) Transistor

Explanation: Active element used in the Hartley oscillator is Transistor for amplification purposes.

10. Hartley oscillator uses which type of feedback?
a) Negative feedback
b) Positive feedback
c) No feedback
d) Positive or Negative depends upon the frequency

Explanation: As normal oscillators, Hartley oscillator also uses positive feedback for sustained oscillation.

Sanfoundry Global Education & Learning Series – Analog Circuits.

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