Question 1

Which of the following biasing combinations is not normally associated with any of the three transistor operating regions?
A) A forward biased E-B junction and a reverse biased C-B junction
B) A reverse biased E-B junction and a reverse biased C-B junction.
C) A reverse biased E-B junction and a forward biased C-B junction.
D) A forward biased E-B junction and a forward biased C-B junction.

Accepted Answer

A reverse biased E-B junction and a forward biased C-B junction is not normally associated with any of the three transistor operating regions.

Question 2

A BJT has values of IE = 12 mA and IB = 600 μA. What is the exact value of beta?
A) 20
B) 21
C) 19
D) None of these are correct.

Accepted Answer

C

Question 3

Ideally, the total collector current through a saturated transistor is determined by
A) The voltage source and the total resistance in the collector and emitter circuits.
B) VCE and VCC.
C) VCC, VCE, and the total base circuit resistance.
D) the transistor.

Accepted Answer

The total collector current in a saturated transistor is primarily determined by the voltage source (VCC) and the total resistance present in the collector and emitter circuits. This is because, in saturation, the transistor acts almost like a closed switch, allowing current to flow based on the external circuit parameters rather than the transistor's characteristics.

Question 4

-The transistor in Figure  is operating in
A) cutoff.
B) saturation.
C) the active region.
D) the limited region.

Accepted Answer

The answer of

-The transistor in Figure  is...

Question 5

Beta β) is the ratio of
A) collector current to emitter current.
B) base current to collector current.
C) collector current to base current.
D) emitter current to collector current.

Accepted Answer

Beta (β) is defined as the ratio of the collector current (Ic) to the base current (Ib), which is represented in choice C.

Question 6

-The transistor in Figure is operating in
A) cutoff.
B) saturation.
C) the active region.
D) the limited region.

Accepted Answer

The answer of

-The transistor in Figure is operating...

Question 7

A BJT has values of IE = 15 mA and IC = 14.95 mA. What is the exact value of beta?
A) 300
B) 299
C) 1.003
D) 250

Accepted Answer

Beta (β) is calculated as the ratio of the collector current (IC) to the base current (IB). Given IC = 14.95 mA and IE = 15 mA, we first find IB = IE - IC = 15 mA - 14.95 mA = 0.05 mA. Then, β = IC / IB = 14.95 mA / 0.05 mA = 299.

Question 8

VCE is measured
A) from the collector terminal to ground.
B) from the collector terminal to the emitter terminal.
C) from the emitter terminal to ground.
D) from the collector-emitter junction to ground.

Accepted Answer

VCE stands for the voltage across the collector-emitter terminals of a transistor, meaning it is measured from the collector terminal to the emitter terminal.

Question 9

When a transistor is in saturation, VCE is approximately equal to
A) VCC.
B) ICRC.
C) 0 V.
D) VE.

Accepted Answer

In saturation, a transistor is fully on, and the collector-emitter voltage (VCE) drops to a very low value, close to 0 V, indicating that the transistor is allowing maximum current to flow from collector to emitter.

Question 10

Under normal circumstances, which BJT terminal currents are approximately equal in value?
A) IC and IB
B) IC and IE
C) IE and IB
D) No two currents are ever approximately equal in value

Accepted Answer

IC and IE are approximately equal in value because the base current IB is much smaller than the collector and emitter currents in a BJT (Bipolar Junction Transistor), making IC ≈ IE in most operating conditions.

Question 11

When a BJT is in cutoff, VCE is approximately equal to
A) VCC.
B) ICRC.
C) 0 V.
D) VE.

Accepted Answer

In cutoff mode, a Bipolar Junction Transistor (BJT) is essentially off, meaning no current flows through the collector-emitter path. As a result, the voltage across the collector-emitter (VCE) is approximately equal to the supply voltage (VCC), since there is minimal voltage drop across the transistor.

Question 12

Bipolar junction transistors BJTs) are commonly used in
A) linear amplifiers.
B) high-speed electronic switches.
C) rectifiers.
D) all of the above.
E) both A and B above.

Accepted Answer

Bipolar junction transistors (BJTs) are widely used in linear amplifiers due to their ability to amplify analog signals, and in high-speed electronic switches because of their fast switching capabilities. They are not typically used as rectifiers; that role is more commonly filled by diodes.

Question 13

-The value of IC in a transistor amplifier is determined by
A) the values of VCC, RC, and VCE.
B) the value of IB for any operating region other than saturation).
C) the value of VCE only.
D) the value of VB.

Accepted Answer

The value of IC (collector current) in a transistor amplifier is primarily determined by the value of IB (base current) for any operating region other than saturation, as per the transistor's operation principles.

Question 14

A BJT has values of α = 0.9985 and IC = 15 mA. What is the value of IB for the component?
A) 22.5 μA
B) 15.15 mA
C) 14.85 mA
D) None of these are correct.

Accepted Answer

The base current $I_B$ can be calculated using the relation between the collector current ($I_C$), the current gain ($\alpha$), and $I_B$, given by $I_C = \alpha I_E + I_B$, where $I_E$ is the emitter current. Since $I_E = I_C + I_B$ and $\alpha = \frac{I_C}{I_E}$, rearranging for $I_B$ gives $I_B = I_C(1 - \alpha) / \alpha$. Substituting the given values, $I_B = 15mA \times (1 - 0.9985) / 0.9985 = 22.5 \mu A$.

Question 15

The condition where increases in IB will not cause further increases in IC is called
A) cutoff.
B) saturation.
C) active operation.
D) limit operation.

Accepted Answer

Saturation in a transistor occurs when increases in the base current (IB) no longer cause increases in the collector current (IC), indicating that the transistor is fully "on" and cannot allow more current through regardless of further increases in IB.

Question 16

The arrow on the BJT schematic symbol identifies
A) the emitter terminal and the type of BJT.
B) the collector terminal and the type of BJT.
C) the base terminal and the type of BJT.
D) none of the above.

Accepted Answer

The arrow on the BJT (Bipolar Junction Transistor) schematic symbol identifies the emitter terminal and indicates whether the BJT is an NPN or PNP type, thus indicating the type of BJT.

Question 17

The BJT is a
A) voltage-controlled device.
B) current-controlled device.
C) frequency-controlled device.
D) power-controlled device.

Accepted Answer

The Bipolar Junction Transistor (BJT) is a current-controlled device, where the input current (base current) controls the output current (collector current).

Question 18

When both BJT junctions are reverse biased, the component is said to be in
A) cutoff.
B) saturation.
C) active operation.
D) limit operation.

Accepted Answer

When both junctions of a Bipolar Junction Transistor (BJT) are reverse biased, the transistor is in the cutoff region, meaning it is essentially off and not conducting current.

Question 19

IC and VCE are directly proportional.

Accepted Answer

IC (collector current) and VCE (collector-emitter voltage) are not directly proportional. In a bipolar junction transistor (BJT) operating in the active region, IC is primarily determined by the base current IB and not significantly affected by VCE.

Question 20

A BJT has a beta rating of 400. What is the value of alpha for the device?
A) 1.0025
B) 0.0025
C) 0.9975
D) None of these are correct.

Accepted Answer

Alpha (α) is related to beta (β) in a BJT by the formula α = β / (β + 1). Substituting β = 400 gives α = 400 / (400 + 1) = 400 / 401 = 0.9975.

Quiz 6: Bipolar Junction Transistors

Which of the following biasing combinations is not normally associated with any of the three transistor operating regions?

A BJT has values of IE = 12 mA and IB = 600 μA. What is the exact value of beta?

Ideally, the total collector current through a saturated transistor is determined by

-The transistor in Figure is operating in

Beta β) is the ratio of

-The transistor in Figure is operating in

A BJT has values of IE = 15 mA and IC = 14.95 mA. What is the exact value of beta?

VCE is measured

When a transistor is in saturation, VCE is approximately equal to

Under normal circumstances, which BJT terminal currents are approximately equal in value?

When a BJT is in cutoff, VCE is approximately equal to

Bipolar junction transistors BJTs) are commonly used in

-The value of IC in a transistor amplifier is determined by

A BJT has values of α = 0.9985 and IC = 15 mA. What is the value of IB for the component?

The condition where increases in IB will not cause further increases in IC is called

The arrow on the BJT schematic symbol identifies

The BJT is a

When both BJT junctions are reverse biased, the component is said to be in

IC and VCE are directly proportional.

A BJT has a beta rating of 400. What is the value of alpha for the device?