Analog Electronics MCQs

1.In a common base amplifier configuration, how does the AC collector voltage relate to the AC base voltage?

The AC voltage at the collector is 180° out of phase with the AC voltage at the baseThe AC voltage at the emitter is 180° out of phase with the AC voltage at the baseThe AC voltage at the collector is in phase with the AC voltage at the baseNone of the above

2.Why is it important to encapsulate a transistor?

To block radio frequency interferenceTo stop photo-emission phenomenaTo prevent the escape of free electronsTo provide mechanical durability

3.A cascade amplifier is formed by connecting which combination of amplifier stages?

Common-collector followed by common-baseCommon-emitter followed by common-baseCommon-base followed by common-collectorCommon-emitter followed by common-collector

4.Three identical amplifiers, each with a voltage gain of 50, an input resistance of 1 kΩ, and an output resistance of 250 Ω, are connected in series. What is the overall open-circuit voltage gain (in dB) of the combined amplifier?

49 dB51 dB98 dB102 dB

5.An operational amplifier with a slew rate of 1 V/µs is configured to provide a gain of 40 dB. To ensure distortion-free amplification of sinusoidal signals from DC up to 20 kHz, what is the maximum allowable input voltage amplitude?

6.Given an npn BJT with transconductance gm = 38 mA/V, capacitances cμ = 10⁻¹⁴ F and cπ = 10⁻¹³ F, and a DC current gain β₀ = 90, what are the values of the cutoff frequency fT and the transition frequency fβ?

fT = 1.64 × 10⁸ Hz and fβ = 1.47 × 10¹⁰ HzfT = 1.47 × 10¹⁰ Hz and fβ = 1.64 × 10⁸ HzfT = 1.33 × 10¹² Hz and fβ = 1.47 × 10¹⁰ HzfT = 1.47 × 10¹⁰ Hz and fβ = 1.33 × 10¹² HzNone of the above

7.When a MOSFET switch is turned on, it can be modeled as which of the following components?

8.Given a transistor with a current gain (β) of 0.98, a collector leakage current (Ico) of 6µA, and a base current (Iβ) of 100µA, what is the collector current (Ic)?

9.What type of feedback does an unbypassed resistor provide in a common emitter amplifier?

Voltage shunt feedbackCurrent series feedbackNegative voltage feedbackPositive current feedback

10.If a differential amplifier has a differential gain of 20,000 and a CMRR of 80 dB, what is the value of its common-mode gain?

11.What type of component can a MOSFET function as?

Capacitor controlled by currentCapacitor controlled by voltageInductor controlled by currentInductor controlled by voltage

12.Among the transistor amplifier configurations listed, which one provides the highest voltage gain?

13.The horizontal intercept of the DC load line corresponds to which ideal transistor condition?

14.What is the highest efficiency achievable in a Class B amplifier?

Nearly 99%Around 85%Up to 50%Approximately 25%

15.Adding a resistor to the emitter terminal of a common amplifier helps stabilize the DC operating point against changes in which factors?

Temperature variations aloneOnly the transistor's current gain (β)Both temperature fluctuations and transistor gain (β) changesNeither temperature nor β variationsNone of these

16.Which type of amplifier is most frequently utilized in sample and hold circuits?

A non-inverting amplifier with unity gainAn inverting amplifier with unity gainAn inverting amplifier set to a gain of 10An inverting amplifier configured for a gain of 100

17.In a full-wave rectifier circuit with two ideal diodes, where Vdc represents the average output voltage and Vm is the maximum voltage across a resistive load, which of the following correctly describes the relationship between Vdc and the peak inverse voltage (PIV) of the diode?

Vdc equals Vm divided by π, and PIV is twice VmVdc is two times Vm divided by π, and PIV equals 2VmVdc is two times Vm divided by π, and PIV equals VmVdc equals Vm divided by π, and PIV equals VmNone of the above