Semiconductor Troubleshooting MCQ Quiz — Part 2 of 5

A. Bias Junction Terminal

B. Basic Junction Thyristor

C. Binary Junction Transducer

D. Bipolar Junction Transistor ✓ Correct answer

A. Both junctions are reverse biased

B. The collector-base junction is forward biased and the emitter-base junction is reverse biased

C. Both junctions are forward biased

D. The emitter-base junction is forward biased and the collector-base junction is reverse biased ✓ Correct answer

A. The emitter ✓ Correct answer

B. All three are doped equally

C. The collector

D. The base

A. IE = IB + IC (emitter current equals the sum of base and collector current) ✓ Correct answer

B. IC = IE + IB

C. IE = IC - IB

D. IB = IE + IC

A. The voltage gain of the transistor

B. The ratio of collector current to base current (IC/IB) ✓ Correct answer

C. The ratio of collector current to emitter current (IC/IE)

D. The ratio of base current to emitter current (IB/IE)

A. A very small base current can control a much larger collector current ✓ Correct answer

B. The base-emitter junction is permanently reverse biased

C. The transistor cannot be used for amplification

D. The transistor will always operate in cutoff

A. So that most carriers injected from the emitter pass through to the collector instead of recombining in the base ✓ Correct answer

B. So that the base can carry the majority of the transistor's total current

C. To increase the transistor's breakdown voltage rating

D. To prevent the transistor from conducting at all

A. Both junctions forward biased

B. Both junctions reverse biased

C. Emitter-base junction reverse biased and collector-base junction forward biased

D. Emitter-base junction forward biased and collector-base junction reverse biased ✓ Correct answer

A. Only the collector-base junction is forward biased

B. The base is left floating (disconnected)

C. Both junctions are reverse biased

D. Both the emitter-base and collector-base junctions are forward biased ✓ Correct answer

A. The collector is shorted to the emitter

B. Both the emitter-base and collector-base junctions are reverse biased ✓ Correct answer

C. Only the emitter-base junction is forward biased

D. Both junctions are forward biased

A. To increase the transistor's voltage gain

B. To set the collector supply voltage

C. To reverse bias the collector-base junction

D. To limit the base current to a safe value that still reliably drives the transistor into saturation ✓ Correct answer

A. There is no fixed phase relationship

B. The output leads the input by 90 degrees

C. The output is inverted, 180 degrees out of phase with the input ✓ Correct answer

D. The output is exactly in phase with the input

A. Very high, often several hundred, with phase inversion

B. Negative and less than -1

C. Approximately 1 (unity), with no phase inversion ✓ Correct answer

D. Exactly zero under all conditions

A. Common collector (emitter follower) ✓ Correct answer

B. Common emitter

C. None of these provide impedance matching

D. Common base with high voltage gain

A. The transistor's maximum power rating

B. The DC bias condition (base current, collector current, and collector-emitter voltage) with no AC signal applied ✓ Correct answer

C. The peak AC output voltage during operation

D. The exact moment the transistor switches fully on

A. It gives perfectly stable bias regardless of transistor replacement

B. It requires no resistors at all to implement

C. It provides very poor thermal stability, allowing the Q-point to drift significantly with temperature and beta variation ✓ Correct answer

D. It only works with PNP transistors, never NPN

A. It eliminates the need for a collector resistor

B. It doubles the transistor's maximum voltage rating

C. It provides a stable Q-point that is largely independent of variations in the transistor's beta ✓ Correct answer

D. It removes the need for any power supply

A. It has no effect on bias stability

B. It increases the transistor's current gain beyond its rated beta

C. It reverse biases the base-emitter junction permanently

D. It provides negative feedback that stabilizes the Q-point against temperature and beta variations ✓ Correct answer

A. A destructive cycle where rising temperature increases collector current, which generates more heat, further increasing current until the transistor is damaged ✓ Correct answer

B. A phenomenon that only affects FETs, not BJTs

C. A normal and desirable characteristic of all amplifier circuits

D. A condition where the transistor cools itself as current increases

A. To increase the transistor's current gain

B. To increase the surface area for dissipating heat, keeping the junction temperature within safe limits ✓ Correct answer

C. To electrically insulate the transistor from the circuit

D. To reduce the transistor's switching speed intentionally

A. A single transistor with two collectors

B. Two transistors connected in parallel to share load current equally with no gain change

C. A transistor combined with a Zener diode for voltage regulation

D. Two transistors connected so the emitter of the first drives the base of the second, giving a very high combined current gain ✓ Correct answer

A. Black probe on the base, red probe on the emitter

B. Neither connection should show any reading

C. Red probe on the base, black probe on the emitter ✓ Correct answer

D. Red probe on the collector, black probe on the base

A. PNP transistors cannot be tested with a multimeter

B. Only the collector-emitter junction can be tested on a PNP transistor

C. The probe polarity is reversed; the black (negative) probe on the base shows forward conduction to the emitter and collector ✓ Correct answer

D. There is no difference at all between NPN and PNP testing

A. The transistor is a healthy PNP type only

B. The transistor has internally shorted and must be replaced ✓ Correct answer

C. The multimeter is set to the wrong voltage range

D. The transistor is functioning completely normally

A. The meter needs to be switched to AC voltage mode

B. The junction is open-circuited internally and the transistor has failed ✓ Correct answer

C. The transistor is working exactly as expected

D. The transistor is a Darlington pair

A. Forward-Emission Transistor; it only works in reverse bias

B. Frequency-Enhanced Transistor; it requires an AC-only supply

C. Fixed-Emitter Transistor; it is identical in operation to a BJT

D. Field-Effect Transistor; it is voltage-controlled rather than current-controlled like a BJT ✓ Correct answer

A. Much lower input impedance

B. Input impedance is not a meaningful FET parameter

C. Exactly the same input impedance as a BJT

D. Much higher input impedance ✓ Correct answer

A. The forward current flowing into the gate terminal

B. The temperature of the drain terminal only

C. The physical rotation of the device

D. The reverse-bias voltage applied to the gate, which controls the width of the depletion region extending into the channel ✓ Correct answer

A. The gate-source voltage at which the channel becomes fully depleted and drain current is reduced to a very small value ✓ Correct answer

B. The supply voltage required to turn the JFET fully on

C. The voltage at which the JFET permanently short circuits

D. The forward voltage drop of the gate-channel junction

A. Zero volts at all times, never varied

B. Negative, meaning the gate is reverse biased with respect to the source ✓ Correct answer

C. Alternating polarity every half cycle regardless of application

D. Positive and forward biased

A. Mechanically Operated Switching Field-Effect Transistor

B. Metal-Oxide-Semiconductor Field-Effect Transistor ✓ Correct answer

C. Modulated Oscillation Semiconductor Field-Effect Type

D. Multi-Output Semiconductor Field-Effect Terminal

A. The gate is completely insulated from the channel by a thin oxide layer, so essentially no DC current flows into the gate ✓ Correct answer

B. The gate is made of a special high-resistance metal alloy

C. The gate is directly connected to the source internally

D. MOSFETs actually have lower input impedance than JFETs

A. OFF, since no conducting channel exists until a sufficient gate voltage is applied to create one ✓ Correct answer

B. Permanently damaged if gate voltage is zero

C. ON, fully conducting until switched off by gate voltage

D. Always in saturation regardless of gate voltage

A. It behaves identically to an enhancement-mode device in every way

B. It cannot conduct current under any bias condition

C. ON, because a conducting channel already exists and gate voltage can be used to deplete (reduce) it ✓ Correct answer

D. OFF, since it requires a gate voltage to create any channel at all

A. Static discharge only affects the MOSFET's case, never its internal structure

B. MOSFETs conduct static electricity better than any other component

C. The extremely thin gate oxide layer can be permanently punctured by the high voltages present in static discharges ✓ Correct answer

D. MOSFETs have no protective packaging of any kind

A. Store them loosely in a plastic bag with leads separated and exposed

B. Apply power to the device before touching its leads

C. Keep the leads shorted together, for example in conductive foam, and use a grounded wrist strap when handling them ✓ Correct answer

D. Handle them only while standing on a carpeted floor

A. The transistor having too high a current gain for any input signal

B. The Q-point being poorly centered or the input signal amplitude being too large, driving the transistor into saturation or cutoff ✓ Correct answer

C. Using a well-centered Q-point with a small input signal

D. The load resistor value being exactly matched to the source impedance

A. Approximately 0.2 V

B. Approximately 12 V

C. Approximately 5 V

D. Approximately 0.6 to 0.7 V ✓ Correct answer

A. It has no measurable effect on circuit behavior

B. The circuit will draw exactly zero current under all conditions

C. The transistor may appear to be partially or fully 'on' even when it should be fully off, causing unintended load activation or excess heat ✓ Correct answer

D. The transistor will always show a perfectly open circuit reading

A. The load resistor is open circuit

B. The transistor has failed with an internal collector-emitter short ✓ Correct answer

C. The supply voltage polarity is reversed

D. The base resistor value is too small

A. The transistor is a Darlington pair

B. An open circuit within one of the transistor's internal junctions, such as an open base-emitter junction ✓ Correct answer

C. The transistor's current gain (beta) is too high

D. The transistor's collector-emitter junction has shorted

A. A clamp meter measuring AC current only

B. An oscilloscope probe alone

C. A standard analog wattmeter

D. A multimeter with a built-in transistor-tester (hFE) socket ✓ Correct answer

A. JFETs require no biasing at all to operate

B. JFETs always provide much higher voltage gain than any BJT circuit

C. JFETs generally exhibit lower input noise and draw negligible gate current, reducing loading effects on sensitive sources ✓ Correct answer

D. JFETs cannot be damaged by static electricity, unlike BJTs

A. A MOSFET is voltage-driven and needs virtually no continuous gate current, simplifying drive circuitry and reducing drive power loss ✓ Correct answer

B. A MOSFET cannot be damaged by excessive drain current under any condition

C. A MOSFET requires a continuous base current proportional to load current, just like a BJT

D. A MOSFET always has a lower voltage rating than any comparable BJT

A. High voltage gain but a current gain of less than 1, along with very low input impedance and no phase inversion ✓ Correct answer

B. Always producing a 180-degree phase-inverted output

C. Extremely high input impedance, higher than common-collector

D. The highest current gain of all three configurations

A. Manufacturers design all transistors to tolerate unlimited current safely

B. Exceeding these ratings can cause excessive heat buildup and permanent damage to the transistor junction ✓ Correct answer

C. The transistor's beta value automatically adjusts to prevent any overcurrent condition

D. Exceeding the ratings only affects the transistor's color coding, not its function

A. It inverts the phase of the signal by 180 degrees before the load

B. It converts the AC signal into a regulated DC voltage

C. It boosts the voltage of the signal by a large factor before the load

D. It matches impedance and supplies the current gain needed to drive the low-impedance load without loading down the source ✓ Correct answer

A. The lead order is universally identical for every TO-92 transistor ever made

B. The flat face of the package always indicates the emitter lead only, regardless of part number

C. The leads are always color-coded red, black, and green

D. The manufacturer's datasheet pinout diagram, since lead order can vary between transistor types and manufacturers ✓ Correct answer

A. Thermal compound is used only for cosmetic purposes

B. Mica washers improve the transistor's current gain

C. The transistor's collector may be internally connected to the metal tab, so insulation prevents an unwanted electrical connection to the grounded heatsink while still conducting heat ✓ Correct answer

D. Insulation is required to prevent the heatsink from melting

A. Pure emitter bias with a dual supply only

B. Fixed base bias with no feedback resistor

C. Zener diode bias applied to the collector only

D. Collector-to-base bias (collector feedback bias) ✓ Correct answer

It is for ITI, diploma and B.Tech students, apprentices and working technicians who want to test fault-finding knowledge. The explanations are written to teach the reason, not just the answer.

Attempt the quiz first without looking. Then open the answer key, read the explanation for every question you missed, and retake the part after a day to see whether the explanation stuck.

No, but the parts build on one another: fundamentals first, then components, then circuits and real-world scenarios. Part 5 is the best test of whether you can apply the earlier parts to a live fault.