1.
Typical burglar alarm systems can usually be powered by any of the following types of power supplies except
Correct Answer
A. 24VAC
Explanation
The question asks for the type of power supply that cannot power typical burglar alarm systems. The options provided are 24VAC, 12VDC, 6VDC, and 24VDC. The correct answer is 24VAC because it is the only option that is not a DC (direct current) power supply. Typical burglar alarm systems require DC power supplies, so 24VAC is not suitable for powering them.
2.
A 7aH battery is designed to deliver
Correct Answer
D. All of the above
Explanation
Battery age, temperature, and other factors may contribute to a lower than expected delivery. Always reserve a 20 percent factor when performing battery calculations.
3.
Battery calculations should always allow for a little extra power in calculating loads. That extra power is usually
Correct Answer
D. 20 percent
Explanation
Battery calculations should always allow for a little extra power in calculating loads. This extra power is usually added as a safety margin to ensure that the battery can handle unexpected fluctuations or variations in the load. By allowing for 20 percent extra power, it ensures that the battery will have enough capacity to meet the demands of the load even in unforeseen circumstances.
4.
A diode is used to
Correct Answer
B. Limit current flow to one direction.
Explanation
A diode is a semiconductor device that allows current to flow in only one direction. It acts as a one-way valve for electric current, allowing it to pass through in one direction while blocking it in the opposite direction. This property of the diode makes it useful for limiting the current flow to one direction in a circuit, preventing any reverse flow. Therefore, the correct answer is "limit current flow to one direction."
5.
The color code on a 42K Ohm resistor would be
Correct Answer
C. Yellow, red, orange
Explanation
The color code on a resistor represents the resistance value. In the given options, the color code "yellow, red, orange" corresponds to a resistance value of 42K Ohms. The first band being yellow represents the digit 4, the second band being red represents the digit 2, and the third band being orange represents the multiplier 1,000. Therefore, the combination of these colors indicates a resistance value of 42,000 Ohms or 42K Ohms.
6.
Which of the following would not be considered an over-current protection device?
Correct Answer
A. Resistor
Explanation
A resistor is not considered an over-current protection device because its purpose is to limit the flow of current in a circuit, rather than protect against excessive current. Resistors are used to control the amount of current flowing through a circuit by providing resistance to the flow of electrons. In contrast, over-current protection devices such as fuses, circuit breakers, and PTCs are specifically designed to detect and interrupt excessive current flow to prevent damage to the circuit or equipment.
7.
LEDs are
Correct Answer
C. Light Emitting Diodes
Explanation
LEDs, or Light Emitting Diodes, are electronic devices that emit light when an electric current passes through them. They are used in various applications such as lighting, displays, and indicators due to their energy efficiency, long lifespan, and compact size. LED technology has become increasingly popular in recent years as it offers significant advantages over traditional lighting sources, including lower energy consumption and reduced environmental impact.
8.
Which of the following statements is true?
Correct Answer
D. Transformers should be matched to the panel power supply specified by the manufacturer.
9.
Exceeding the manufacturer’s listed draw on aux power by less than 10 percent is acceptable because they underrate the power supply for that purpose.
Correct Answer
B. False
Explanation
The statement suggests that it is acceptable to exceed the manufacturer's listed draw on aux power by less than 10 percent because they underrate the power supply for that purpose. However, the correct answer is false. Exceeding the manufacturer's listed draw on aux power, even by less than 10 percent, is not acceptable as it can potentially damage the power supply or other components. It is important to adhere to the manufacturer's specifications to ensure safe and proper functioning of the equipment.
10.
Current flows with the least amount of resistance through which wire?
Correct Answer
D. 6AWG
Explanation
The smaller the number, the larger the wire size.
11.
Which of the following is a resettable device?
Correct Answer
C. Circuit Breaker
Explanation
A circuit breaker is a resettable device that is used to protect electrical circuits from overloads and short circuits. It automatically interrupts the flow of electricity when it detects a fault, preventing damage to the circuit and potential fire hazards. Unlike a fuse, which needs to be replaced after it is blown, a circuit breaker can be reset by simply switching it back on after the fault has been resolved. Therefore, a circuit breaker is the correct answer as it can be reset and reused multiple times.
12.
Amperage and voltage are the same.
Correct Answer
B. False
Explanation
Volts and amps are two of the three components of Ohm’s Law. The third is resistance.
13.
Which of the following is correct?
Correct Answer
A. 420mA+1A+0.6A=2.02A
Explanation
To perform your calculations, remember that 1000mA is equal to 1 Amp.
14.
Which of the following will provide power for the greatest amount of time?
Correct Answer
D. 4 4 volt, 24 Amp batteries wired in parallel
Explanation
The 4 4 volt, 24 Amp batteries wired in parallel will provide power for the greatest amount of time because when batteries are wired in parallel, their capacities add up. Therefore, the total capacity of the batteries in this option is 4 times the capacity of a single battery, which is 24 Amps. This is greater than the capacities of the other options, making it the correct answer.
15.
A UPS
Correct Answer
B. Is backup battery power supply that engages during a light and power source outage and has a limited amount of current it can deliver.
Explanation
The correct answer is "is a backup battery power supply that engages during a light and power source outage and has a limited amount of current it can deliver." This explanation accurately describes a UPS (Uninterruptible Power Supply), which is a device that provides backup power to electrical devices in the event of a power outage. It uses batteries to store energy and deliver it when the main power source is unavailable. The statement also mentions that a UPS has a limited amount of current it can deliver, highlighting an important characteristic of this type of power supply.