1 $In a Bipolar Junction Transistor (BJT), which region is the most heavily doped?$

A.

Base

B.

Collector

C.

Emitter

D.

Both Base and Collector

2 $Which of the following correctly describes the physical size of the three regions in a BJT?$

A.

Base > Emitter > Collector

B.

Collector > Emitter > Base

C.

Emitter > Collector > Base

D.

Base > Collector > Emitter

3 $What does the term 'Bipolar' in Bipolar Junction Transistor refer to?$

A.

The device has two poles

B.

The conduction is due to two types of charge carriers: electrons and holes

C.

The device operates in two regions: active and saturation

D.

The device has two PN junctions

4 $In the symbol of a BJT, the arrow on the emitter indicates the direction of:$

A.

Electron flow

B.

Conventional current flow

C.

Hole drift

D.

Base current only

5 $What is the relationship between the emitter current (), base current (), and collector current () in a BJT?$

A.

B.

C.

D.

6 $The common-base current gain is denoted by . What is its typical value?$

A.

Between 0.95 and 0.99

B.

Between 10 and 100

C.

Exactly 1

D.

Less than 0.5

7 $The relationship between common-emitter current gain () and common-base current gain () is given by:$

A.

B.

C.

D.

8 $If a transistor has a of 99, what is the value of ?$

A.

0.99

B.

1.01

C.

0.98

D.

0.999

9 $Which of the following describes the biasing of junctions for a BJT operating in the active region?$

A.

Emitter-Base junction forward-biased, Collector-Base junction forward-biased

B.

Emitter-Base junction reverse-biased, Collector-Base junction reverse-biased

C.

Emitter-Base junction forward-biased, Collector-Base junction reverse-biased

D.

Emitter-Base junction reverse-biased, Collector-Base junction forward-biased

10 $When a BJT acts as a closed switch (ON state), it operates in which region?$

A.

Active region

B.

Cut-off region

C.

Saturation region

D.

Breakdown region

11 $When a BJT acts as an open switch (OFF state), it operates in which region?$

A.

Active region

B.

Cut-off region

C.

Saturation region

D.

Inverse-active region

12 $The collector leakage current in a common-emitter configuration is related to the common-base leakage current by:$

A.

B.

C.

D.

13 $Which BJT configuration provides the highest voltage gain but a current gain of less than unity?$

A.

Common-Emitter (CE)

B.

Common-Collector (CC)

C.

Common-Base (CB)

D.

Both CE and CC

14 $Which BJT configuration is also known as an 'Emitter Follower'?$

A.

Common-Base (CB)

B.

Common-Emitter (CE)

C.

Common-Collector (CC)

D.

Common-Drain (CD)

15 $Which configuration is most widely used for audio frequency power amplification due to its high power gain?$

A.

Common-Base (CB)

B.

Common-Emitter (CE)

C.

Common-Collector (CC)

D.

Common-Gate (CG)

16 $What is the phase difference between the input and output voltage signals in a Common-Emitter (CE) amplifier?$

A.

B.

C.

D.

17 $The input characteristics of a CE configuration are plotted as a graph between:$

A.

and at a constant

B.

and at a constant

C.

and at a constant

D.

and at a constant

18 $The output characteristics of a CE configuration are plotted as a graph between:$

A.

and at a constant

B.

and at a constant

C.

and at a constant

D.

and at a constant

19 $What phenomenon occurs when the reverse-bias voltage increases, causing the effective base width to decrease?$

A.

Zener effect

B.

Avalanche effect

C.

Early effect

D.

Hall effect

20 $Which of the following BJT configurations is best suited for impedance matching (connecting a high impedance source to a low impedance load)?$

A.

Common-Base (CB)

B.

Common-Emitter (CE)

C.

Common-Collector (CC)

D.

None of the above

21 $What is the primary purpose of transistor biasing?$

A.

To increase the voltage gain

B.

To establish a stable DC operating point (Q-point)

C.

To decrease the input impedance

D.

To invert the input signal

22 $The DC load line is a straight line drawn on the output characteristics of a transistor. What does its slope represent?$

A.

B.

C.

D.

23 $On a DC load line, the point where the line intersects the Y-axis (axis) corresponds to which condition?$

A.

Ideal Cut-off

B.

Ideal Saturation

C.

Active operating point

D.

Breakdown point

24 $On a DC load line, the point where the line intersects the X-axis (axis) corresponds to which condition?$

A.

Ideal Cut-off

B.

Ideal Saturation

C.

Active operating point

D.

Quiescent point

25 $For a faithful amplification without clipping, where should the Operating Point (Q-point) ideally be located?$

A.

Near the saturation region

B.

Near the cut-off region

C.

Exactly at the origin

D.

In the middle of the active region on the DC load line

26 $In a silicon BJT operating as a switch in the saturation region, what is the typical value of ?$

A.

B.

C.

D.

27 $In a Fixed Bias circuit, what is the formula for the base current ?$

A.

B.

C.

D.

28 $Why is the Fixed Bias circuit rarely used in practical amplifier applications?$

A.

It requires too many components

B.

The Q-point is highly unstable and dependent on temperature and

C.

It provides very low voltage gain

D.

It draws too much power from the power supply

29 $The Stability Factor with respect to leakage current is defined as:$

A.

B.

C.

D.

30 $What is the stability factor for a standard Fixed Bias circuit?$

A.

B.

C.

D.

31 $What is Thermal Runaway in a BJT?$

A.

The melting of the transistor casing due to high external temperature

B.

A self-destructive process where increased temperature increases leakage current, increasing power dissipation, leading to further temperature rise

C.

The sudden drop in at high temperatures causing the transistor to turn off

D.

The increase of drop beyond due to localized heating

32 $In an Emitter Feedback Bias circuit, the inclusion of the emitter resistor provides which type of feedback?$

A.

Positive voltage feedback

B.

Positive current feedback

C.

Negative current feedback

D.

Negative voltage feedback

33 $In a Voltage Divider Bias (or Emitter Bias) circuit, how does the stability factor compare to that of a Fixed Bias circuit?$

A.

It is much higher

B.

It is much lower (closer to 1)

C.

It is exactly the same

D.

It is negative

34 $What is the primary function of an Emitter Bypass Capacitor () in an amplifier circuit?$

A.

To block DC voltage from the power supply

B.

To provide an AC short circuit across the emitter resistor to prevent a drop in AC voltage gain

C.

To improve the DC stability factor

D.

To couple the output signal to the load

35 $In a typical BJT datasheet, the parameter refers to:$

A.

AC current gain ()

B.

DC current gain ()

C.

Common-base current gain ()

D.

Input impedance

36 $In a BJT datasheet, what does the parameter (Transition Frequency) denote?$

A.

The frequency at which the transistor burns out

B.

The frequency at which the common-emitter current gain drops to unity (1)

C.

The minimum operating frequency of the transistor

D.

The resonant frequency of the parasitic capacitances

37 $What does the Maximum Power Dissipation rating () on a BJT datasheet specify?$

A.

The amount of power the BJT supplies to the load

B.

The maximum AC power the transistor can output

C.

The maximum safe product of and the transistor can withstand without overheating

D.

The power required to turn on the transistor

38 $Which leakage current roughly doubles for every rise in temperature for a silicon transistor?$

A.

B.

C.

D.

39 $On a transistor datasheet, represents the maximum voltage between:$

A.

Collector and Base with Emitter open

B.

Collector and Emitter with Base open

C.

Collector and Emitter with Base shorted to Emitter

D.

Base and Emitter with Collector open

40 $Which of the following describes the Safe Operating Area (SOA) of a power BJT?$

A.

A region on the load line where the gain is highest

B.

The range of input frequencies it can amplify

C.

A graphical boundary defined by max current, max voltage, max power dissipation, and secondary breakdown limits

D.

The physical space required around the transistor on a PCB

41 $In an NPN transistor, the majority charge carriers in the base region are:$

A.

Electrons

B.

Holes

C.

Both electrons and holes

D.

Ions

42 $If the base current is and, what is the collector current ?$

A.

B.

C.

D.

43 $Why is a coupling capacitor used at the input of a BJT amplifier?$

A.

To increase the DC voltage level

B.

To filter out high-frequency noise

C.

To block DC from the input signal source while allowing AC signals to pass

D.

To prevent thermal runaway

44 $What happens if the Q-point is selected too close to the cut-off region on the DC load line?$

A.

The positive half-cycle of the output voltage may be clipped

B.

The amplifier will have zero voltage gain

C.

Thermal runaway will occur immediately

D.

The transistor will permanently remain in saturation

45 $The derating factor of a BJT tells us how to reduce the maximum power rating based on:$

A.

The operating frequency

B.

The load resistance

C.

An increase in ambient or case temperature

D.

The age of the component

46 $For a PNP transistor, the active region requires which polarities relative to the base?$

A.

Emitter is negative, Collector is positive

B.

Emitter is positive, Collector is negative

C.

Both Emitter and Collector are positive

D.

Both Emitter and Collector are negative

47 $A transistor acting as a switch in an electronic robot circuit is typically driven by:$

A.

A pure sinusoidal wave

B.

A constant DC voltage matching the Q-point

C.

A digital signal (High/Low) like PWM

D.

A low-amplitude audio signal

48 $The parameter 'Thermal Resistance' () found on a datasheet is critical for calculating:$

A.

The required base bias resistor

B.

The value of the coupling capacitor

C.

The size of the heat sink required

D.

The transition frequency limits

49 $In BJT action, what is the 'Emitter Injection Efficiency' ()?$

A.

The ratio of minority carriers reaching the collector to those injected by the emitter

B.

The ratio of current from injected majority carriers to the total emitter current

C.

The efficiency of the power supply

D.

The ratio of output voltage to input voltage

50 $Fundamentally, a Bipolar Junction Transistor acts as a:$

A.

Voltage-controlled voltage source

B.

Voltage-controlled current source

C.

Current-controlled current source

D.

Current-controlled voltage source

Unit 2 - Practice Quiz