Subtopics in this chapter
- 1.1Basic concept
- 1.2Network theorems
- 1.3Alternating current fundamentals
- 1.4Semiconductor devices
- 1.5Signal generator
- 1.6Amplifiers
What is usually tested
Expect direct questions on circuit laws and definitions: Ohm's and Kirchhoff's laws, series and parallel circuits, star-delta conversion, and the network theorems (superposition, Thevenin, Norton, maximum power transfer). AC questions cover rms and average values, resonance, power factor and three-phase relations. In electronics, the favourites are diode behaviour, BJT configurations and biasing, MOSFET and CMOS basics, oscillator types and conditions, amplifier classes and ideal op-amp properties.
Sample questions with answers
Choose an answer to check it, or open "Show answer". These 12 are taken from the 452 questions for this chapter in the practice bank.
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The SI unit of inductance is:
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Answer: A. Henry
Inductance is measured in henry (H).
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Kirchhoff's Current Law is based on the conservation of:
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Answer: A. Charge
KCL: total current entering a node equals total current leaving, i.e., charge is conserved.
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In a series RLC circuit at resonance, the impedance is:
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Answer: C. Purely resistive
At resonance XL = XC, they cancel, leaving only resistance.
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The superposition theorem can be applied only to circuits that are:
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Answer: D. Linear
The total response is the sum of the responses to each source alone only if the circuit is linear.
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The generation of alternating voltage in an alternator is based on:
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Answer: A. Faraday's law of electromagnetic induction
An emf is induced in a coil whenever the magnetic flux linking it changes.
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In the expression e = Em sin(wt) for an alternating emf, the quantity w is the:
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Answer: C. Angular frequency
The angular frequency is 2 x pi x f, in radians per second.
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A p-n junction diode in forward bias offers:
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Answer: B. Low resistance
Forward bias lowers the barrier, allowing current to flow with low resistance.
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An n-type semiconductor is produced by doping pure silicon with:
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Answer: A. A pentavalent impurity such as phosphorus
Each pentavalent atom donates one free electron, so electrons are the majority carriers.
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An oscillator is a circuit that:
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Answer: C. Produces a periodic output without any external input signal
It converts DC power from the supply into an AC signal.
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The type of feedback used in an oscillator is:
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Answer: D. Positive feedback
Part of the output is fed back in phase with the input so that the signal sustains itself.
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The main function of the output stage of an amplifier is to:
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Answer: A. Deliver the required signal power to the load efficiently
The output stage must have a low output resistance and supply large currents with little distortion.
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In a class A output stage, the transistor conducts for:
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Answer: B. The full 360 degrees of the input cycle
The transistor is biased at the middle of its operating range and never turns off.
Practise this chapter
The full mock tests mix 10 questions from this chapter with 10 from each of the other nine, under the real 2-hour limit. Chapter practice mode lets you work through this chapter alone, untimed, with the explanation shown after every question. Go to the mock tests