Question 1

-Is the circuit in Figure midpoint biased?

Accepted Answer

B

Question 2

The most commonly used type of transistor biasing is

Accepted Answer

Voltage-divider bias is the most commonly used type of transistor biasing because it provides excellent stability of the operating point independent of the transistor's beta (β) value or variations in temperature.

Question 3

The term quiescent means

Accepted Answer

Quiescent means being at a state of inactivity or being at rest, which does not imply being midpoint biased or active.

Question 4

What is the primary drawback to using emitter bias?

Accepted Answer

Emitter bias requires a dual-polarity power supply, which can be a limitation in some applications due to increased complexity and cost.

Question 5

As temperature increases, the value of hFE

Accepted Answer

As temperature increases, the minority carrier concentration increases, which in turn increases the base current. This results in a decrease in hFE.

Question 6

-The value of VCEoff) for the circuit in Figure is

Accepted Answer

VCEoff) = VCC - VBE = 20 V - 10 V = 10 V

Question 7

-The value of ICsat) for the circuit in Figure is

Accepted Answer

The answer of

-The value of ICsat) for the...

Question 8

An emitter bias circuit has values of VCC = +8 V and VEE = -8 V. The value of VCEoff) for the circuit is

Accepted Answer

VCE(off) is the collector-emitter voltage when the transistor is in the cutoff state, essentially when it is turned off. In an emitter bias circuit, VCE(off) is calculated by taking the difference between the supply voltages VCC and VEE, which in this case is +8 V - (-8 V) = 16 V.

Question 9

Why is midpoint bias desirable for most linear amplifiers?

Accepted Answer

Midpoint bias is desirable because it allows the amplifier to operate optimally for AC signals, ensuring that the output signal is not distorted and can swing equally in both directions from the quiescent point.

Question 10

The value of ICsat) for the circuit in Figure  is

Accepted Answer

IC(sat) refers to the saturation current of the transistor, which is the maximum current that can flow through the collector-emitter junction when the transistor is fully on. To determine this value, we need to consider the circuit's configuration, including the supply voltage, the resistors in the circuit, and the transistor's characteristics. Without the specific figure or circuit details, a general approach to find IC(sat) involves using Ohm's law and the transistor's saturation condition. The correct answer would typically depend on these details, but given only the choices, the explanation is based on common circuit analysis principles.

Question 11

-The value of VCEoff) for the circuit in Figure  is

Accepted Answer

VCE(off) is the collector-emitter voltage when the transistor is in the cutoff state, meaning no base current is flowing, and the transistor is off. In this state, the transistor behaves like an open switch, so VCE would equal the supply voltage, which is 10 V.

Question 12

The change in ICQ and VCEQ that can occur when temperature changes is known as

Accepted Answer

The change in ICQ and VCEQ due to temperature variations is referred to as Q-point shift. This term describes how the quiescent or operating point of a transistor amplifier circuit can move or shift with changes in temperature, affecting the circuit's performance.

Question 13

Which of the following is the likely to experience significant changes in the values of ICQ and VCEQ as a result of changes in temperature?

Accepted Answer

Base bias circuits are highly sensitive to variations in temperature because they lack any form of feedback to stabilize the operating point. Changes in temperature can significantly affect the base-emitter voltage and, consequently, the collector current (ICQ) and collector-emitter voltage (VCEQ). Other biasing methods, like voltage-divider, emitter-feedback, and collector-feedback bias, incorporate feedback mechanisms that help stabilize the operating point against temperature variations and transistor parameter changes.

Question 14

Which of the following is a characteristic of emitter bias ?

Accepted Answer

Emitter bias typically involves a low emitter potential and a base potential close to 0 V, but not necessarily a collector potential equal to VCC.

Question 15

The spec sheet for a given transistor contains the following table: hFE = 5 to 200 when IC = 1 mA hFE = 70 to 350 when IC = 10 mA hFE = 100 to 400 when IC = 20 mA hFE = 150 to 450 when IC = 100 mA
The transistor is being used in a circuit with the following values: VCC = 20 V, RC = 820 Ω, and RE = 180 Ω. What value of hFE should be used in the analysis of the circuit?

Accepted Answer

The value of hFE should be chosen based on the operating current. Assuming the circuit is designed to operate around IC = 10 mA, the typical hFE value would be around the midpoint of the range given for that current, which is approximately 157.

Question 16

Base bias is used primarily in switching applications.

Accepted Answer

Base bias is a method of biasing a transistor that is commonly used in switching applications due to its simplicity and ability to quickly turn the transistor on and off.

Question 17

The simplest transistor biasing circuit is called

Accepted Answer

Base bias is considered the simplest form of transistor biasing because it involves directly applying a DC bias voltage to the base of the transistor relative to its emitter. This method is straightforward but can lead to stability issues with variations in temperature or transistor beta (β) values.

Question 18

-Is the circuit in Figure  midpoint biased?

Accepted Answer

Midpoint biasing is a technique used in amplifiers to set the operating point at the center of the load line, allowing for maximum symmetrical signal swing. If the circuit is designed with this in mind, it is midpoint biased.

Question 19

A transistor has a rating of hFE = 50 to 450. What value of hFE should be used for circuit analysis purposes?

Accepted Answer

The answer of A transistor has a rating of hFE...

Question 20

-Is the amplifier in Figure midpoint biased?

Accepted Answer

Midpoint biasing refers to a specific method of biasing a transistor in an amplifier circuit to ensure it operates in the active region for both halves of an input signal. Without seeing the figure, we cannot definitively say if the amplifier is midpoint biased. However, the question implies doubt about the biasing method, suggesting the correct answer is that it is not midpoint biased.

Quiz 7: DC Biasing Circuits

-Is the circuit in Figure midpoint biased?

The most commonly used type of transistor biasing is

The term quiescent means

What is the primary drawback to using emitter bias?

As temperature increases, the value of hFE

-The value of VCEoff) for the circuit in Figure is

-The value of ICsat) for the circuit in Figure is

An emitter bias circuit has values of VCC = +8 V and VEE = -8 V. The value of VCEoff) for the circuit is

Why is midpoint bias desirable for most linear amplifiers?

The value of ICsat) for the circuit in Figure is

-The value of VCEoff) for the circuit in Figure is

The change in ICQ and VCEQ that can occur when temperature changes is known as

Which of the following is the likely to experience significant changes in the values of ICQ and VCEQ as a result of changes in temperature?

Which of the following is a characteristic of emitter bias ?

Base bias is used primarily in switching applications.

The simplest transistor biasing circuit is called

-Is the circuit in Figure midpoint biased?

A transistor has a rating of hFE = 50 to 450. What value of hFE should be used for circuit analysis purposes?

-Is the amplifier in Figure midpoint biased?