All Free Electrical Engineering MCQs with Answers

• A. equal to the positive supply voltage
• B. equal to the negative supply voltage
• C. equal to zero
• D. equal to CMRR

Explanation: With equal zero-voltage inputs, the ideal differential input voltage is zero, so the ideal op-amp output is also zero.

• A. both inputs are grounded
• B. the outputs are connected together
• C. an identical signal appears on both the inputs
• D. the output signal are in-phase

Explanation: Common-mode operation means the same voltage signal is applied simultaneously to both inputs.

• A. half of either collector current
• B. equal to either collector current
• C. two times either collector current
• D. equal to the difference in base currents

Explanation: The tail current is the sum of the two transistor collector currents. With balanced inputs, each collector carries half the tail current…

• A. increases
• B. decreases
• C. is not affected
• D. depends on Ri

Explanation: Opening the feedback resistor removes negative feedback, causing the amplifier gain to rise toward the much larger open-loop gain.

• A. has a voltage gain of 1
• B. is noninverting
• C. has no feedback resistor
• D. has all of these

Explanation: A voltage follower uses 100% negative feedback, giving a closed-loop voltage gain of approximately 1 without phase inversion.

• A. difference between two base currents
• B. average of two base currents
• C. collector current divided by current gain
• D. none of these

Explanation: Input offset current is the magnitude of the difference between the two input bias currents, written as |I_B1 − I_B2|.

• A. difference between two emitter currents
• B. sum of two emitter currents
• C. collector current divided by current gain
• D. collector voltage divided by collector resistance

Explanation: The tail current is the total current supplied to the two transistor emitters, so it equals I_E1 + I_E2.

• A. the noninverting input
• B. the inverting input
• C. both iputs
• D. top of the tail resistor

Explanation: A common-mode signal is the same signal applied simultaneously to both inputs of a differential amplifier.

• A. differential amplifier
• B. class B push-pull amplifier
• C. CE amplifier
• D. swamped amplifier

Explanation: The differential input stage allows an op-amp to amplify the voltage difference between its two inputs while rejecting common-mode…

• A. a mechanical ground
• B. an a.c. ground
• C. a virtual ground
• D. an ordinary ground

Explanation: A virtual ground is maintained at approximately 0 V by circuit action but has no direct physical connection to ground, so it is not a path…

• A. Is increased
• B. Is decreased
• C. Remains the same
• D. None of the above

Explanation: Making the CRT control grid more negative repels more electrons from the beam, reducing the beam current.

• A. Silicon
• B. Germanium
• C. Copper
• D. None of the above

Explanation: Silicon is the standard material for most ICs because it forms reliable semiconductor junctions and a useful insulating SiO₂ layer.

• A. Transistors
• B. Diodes
• C. Resistors
• D. Large inductors and transformers

Explanation: Transistors, diodes, and practical resistors can be fabricated on an IC, but large inductors and transformers require bulky magnetic…

• A. A resistor
• B. An insulating layer
• C. Mechanical output
• D. None of the above

Explanation: The SiO₂ layer is electrically insulating and is used for isolation and, in MOS devices, as the gate dielectric.

• A. Resistors
• B. Capacitors
• C. Transistors and diodes
• D. None of the above

Explanation: Transistors and diodes are active components because they control or rectify electrical signals, while resistors and capacitors are…

• A. Very large
• B. Large
• C. Extremely small
• D. None of the above

Explanation: An integrated circuit places many components on one semiconductor chip, so its physical size is extremely small compared with a circuit…

• A. Thin films
• B. Monolithic
• C. Hybrid
• D. None of the above

Explanation: Monolithic ICs are formed on a single semiconductor substrate and are the most commonly used type because they are compact, reliable, and…

• A. Digital
• B. Linear
• C. Both digital and linear
• D. None of the above

Explanation: Computers mainly perform logic and arithmetic using binary states, so their integrated circuits are predominantly digital rather than…

• A. Digital IC
• B. Linear IC
• C. Both digital and linear IC
• D. None of the above

Explanation: An audio amplifier must continuously amplify varying voltage or current waveforms, making it a linear IC application.

• A. Thin-film
• B. Hybrid
• C. Thick-film
• D. Monolithic

Explanation: Monolithic ICs, in which all components are fabricated on one chip, are the most widely used because mass production makes them small…