1.
What is the definition of impedance?
Correct Answer
A. A Combination Of Resistance And Reactance, Expressed In Ohms
Explanation
Impedance is defined as a combination of resistance and reactance, expressed in ohms. Resistance refers to the opposition to the flow of electric current, while reactance refers to the opposition to the change in electric current caused by inductance or capacitance. Impedance takes into account both of these factors and is measured in ohms. Therefore, the correct answer is "A Combination Of Resistance And Reactance, Expressed In Ohms."
2.
What is the value of a resistor that has the following color bands: red, red, red, gold?
Correct Answer
B. 2.2k Ohms, 5%
Explanation
The value of a resistor can be determined by interpreting the color bands on it. In this case, the color bands are red, red, red, gold. The first three red bands indicate a value of 2, and the gold band represents a tolerance of 5%. Therefore, the value of the resistor is 2.2k Ohms with a tolerance of 5%.
3.
What is the SI unit for potential difference?
Correct Answer
B. Volt
Explanation
The SI unit for potential difference is the volt. Potential difference, also known as voltage, is the measure of the electric potential energy per unit charge between two points in a circuit. It is measured in volts and represents the amount of work done to move a unit of charge from one point to another. Current, ampere, and watt are all related to electrical measurements, but they do not represent the SI unit for potential difference.
4.
Two resistors are wired in parallel. Which of the following statements is true?
Correct Answer
A. The Total Resistance Will Be Less Than The Sum Of The Two
Explanation
When two resistors are wired in parallel, the total resistance will be less than the sum of the two resistors. This is because in a parallel circuit, the current has multiple paths to flow through, and each resistor offers a different path of resistance. As a result, the total resistance is reduced compared to having just one resistor. This can be calculated using the formula: 1/RTotal = 1/R1 + 1/R2, where RTotal is the total resistance and R1 and R2 are the resistances of the individual resistors.
5.
Name the three leads of a field-effect transistor (FET)?
Correct Answer
A. Source, Gate, And Drain
Explanation
The three leads of a field-effect transistor (FET) are the Source, Gate, and Drain. The Source is the terminal through which current enters the transistor, the Gate controls the flow of current, and the Drain is the terminal through which current exits the transistor.
6.
What is an inductor called that is designed for the specific purpose of passing DC while blocking AC?
Correct Answer
C. Choke
Explanation
A choke is an inductor that is specifically designed to allow the flow of direct current (DC) while blocking alternating current (AC). It is used to filter out unwanted AC signals in electronic circuits, allowing only the desired DC signal to pass through. Rectifier diodes and triacs are not specifically designed for this purpose, making them incorrect choices.
7.
A capacitor is best described by which one of the following statements?
Correct Answer
A. A Device That Store Electrical Energy And Blocks The Flow Of DC
Explanation
A capacitor is a device that stores electrical energy and blocks the flow of direct current (DC). It consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied across the plates, the capacitor stores energy in an electric field. It can release this stored energy when needed, making it useful for various applications such as energy storage, filtering, and timing circuits. The capacitor does not amplify current or provide resistance, and it can also allow the flow of alternating current (AC) depending on the frequency and capacitance value.
8.
The electron flow in a circuit passes through a NPN transistor from _________ to ___________?
Correct Answer
A. Emitter, Collector
Explanation
In a NPN transistor, the electron flow occurs from the emitter to the collector. The emitter is the region where the majority carriers (electrons) are emitted, while the collector is the region where these majority carriers are collected. Therefore, the correct answer is "Emitter, Collector".
9.
What is the main difference between the function of a SCR and a triac?
Correct Answer
D. The Scr Can Be Triggered In Only One Direction, While The Triac Can Be Switched On In Either Direction
Explanation
The main difference between the function of a SCR (Silicon Controlled Rectifier) and a triac is that the SCR can be triggered in only one direction, while the triac can be switched on in either direction. This means that the SCR can only conduct current in one direction, while the triac can conduct current in both directions. This makes the triac more versatile and suitable for applications where bidirectional current flow is required.
10.
What is the distinguishing feature of a thyristor?
Correct Answer
A. A Momentary Pulse Of Gate Current Switches Them On
Explanation
A distinguishing feature of a thyristor is that it can be switched on by a momentary pulse of gate current. This means that the thyristor can be controlled and turned on by a short burst of current applied to its gate terminal. This feature allows for precise control and operation of the thyristor in various applications.
11.
In a basic transistor circuit, what is the most significant factor in determining if a transistor performs as a switch or as an amplifier?
Correct Answer
C. The Control Circuit
Explanation
The control circuit is the most significant factor in determining if a transistor performs as a switch or as an amplifier. The control circuit controls the biasing and base current of the transistor, which determines its operating mode. In switch mode, the control circuit provides enough base current to fully saturate the transistor, turning it on like a closed switch. In amplifier mode, the control circuit provides a small base current to operate the transistor in its active region, allowing it to amplify the input signal. Therefore, the control circuit plays a crucial role in determining the transistor's functionality.
12.
Why are PNP transistors used less often than NPN transistors?
Correct Answer
A. Pnps Switch Slower And Are Generally More Expensive Than Npns
Explanation
PNP transistors are used less often than NPN transistors because they switch slower and are generally more expensive. The switching speed of a transistor is an important factor in many applications, especially in high-frequency circuits. NPN transistors have faster switching times compared to PNP transistors, making them more suitable for many electronic devices. Additionally, the cost of PNP transistors is generally higher due to their less common usage and lower availability in the market. Therefore, NPN transistors are preferred in most cases due to their faster switching speed and lower cost.
13.
A P-channel enhancement type MOSFET performs much the same function as a PNP transistor. What is the main difference?
Correct Answer
C. A Mosfet Is Controlled By Voltage Rather Than Current
Explanation
The main difference between a P-channel enhancement type MOSFET and a PNP transistor is that the MOSFET is controlled by voltage rather than current. In a MOSFET, the gate voltage controls the flow of current between the source and the drain terminals. This voltage-controlled operation allows for faster switching and better control over the current flow compared to a PNP transistor, which is controlled by current.
14.
Why is a transistor defined as a an amplifying device?
Correct Answer
B. The Current In The Output Circuit Is Greater Than The Current In The Input Circuit
Explanation
A transistor is defined as an amplifying device because the current in the output circuit is greater than the current in the input circuit. Transistors are used to amplify electrical signals, meaning they increase the strength or amplitude of the signal. This is achieved by controlling the flow of current between the input and output circuits. By increasing the current in the output circuit compared to the input circuit, the transistor effectively amplifies the signal.