3rd year final

Question 1

The process by which impurities are added to a semiconducting material to change its electric characteristics is called.

Answer 1

Doping

Question 2

When voltage is applied to a diode, the action occuring in the ____ region either blocks current flow or passes current.

Answer 2

Depletion

Question 3

Capacitive filter elements can be used for smoothing the output _____ across the load.

Answer 3

voltage

Question 4

A diode will conduct normal current when the ___ is positive with respect to the_____.

Answer 4

Anode, cathode

Question 5

The ____ converts AC to a pulsating DC voltage.

Answer 5

Rectifier

Question 6

What determines the load polarity of a power supply the that converts AC to DC?

Answer 6

diode

Question 7

P-Type semiconductors have been doped with a_____ of free electrons.

Answer 7

Deficiency

Question 8

When testing a Zener diode with a Vom your readings indicate a low resistance in both directions, you could probably conclude the Zener diode is _____.

Answer 8

Shorted

Question 9

The primary purpose of a Zener diode is to act as a ______.

Answer 9

Voltage regulator

Question 10

List 4 ways that Diodes can be used in signal and power circuits.

Answer 10

1. Detectors of Radio Waces
2. Logic Functions
3. Switching
4. Signal mixers

Question 11

Regardless of the way an SCR is shut down, the process is called _____.

Answer 11

Commutation

Question 12

An SCR stays off until a point called ____ breakover voltage is reached.

Answer 12

Forward

Question 13

A ____ device has the ability to produce a voltage in the presence of light.

Answer 13

Photovoltaic

Question 14

The first automatic fire alarm detection device was a _____.

Answer 14

Fuseable link heat detector

Question 15

A_____switch is not a supervisory switch.
a.Room temp b.Vane type flow C.Valve tamper
D.Water Level

Answer 15

B.Vane type flow

Question 16

The most appropriate detection for an atrium is a ____.

Answer 16

Projected beam smoke detector

Question 17

A short circuit on a fire alarm initiating device circuit causes a ____ signal.

Answer 17

Trouble

Question 18

The minimum sound pressure level for an audible fire alarm notification appliance at the pillow in a sleeping area is _____ dBA.

Answer 18

75

Question 19

A firestopping material that expands when heated is referred to as ______.

Answer 19

Intumescent

Question 20

What is the maximum distance that visible notification appliances must be located from the end of a corridor?

Answer 20

15 ft

Question 21

There are five primary functions of a fire alarm system. Name Four

Answer 21

1. Early Detection
2. Occupant notification
3. Safely control functions
4. Building systems management

Question 22

Non power-limited fire alarm systems have a maximum operating voltage of ____volts.

Answer 22

600

Question 23

Upon detection of a trouble condition, fire alarm system controls must initiate a trouble signal within ____ seconds.

Answer 23

200

Question 24

Name 3 types of supervising stations systems

Answer 24

1. Central
2. Remote
3. Proprietary

Question 25

List the four emergency control functions that may be controlled by a fire alarm system.

Answer 25

1. Elevator recall 2. HVAC shutdown 3. Door unlocking 4. Stairway pressurization

Question 26

Name the three basic parts of fire protection

Answer 26

1. Detection 2. Containment 3. Suppression

Question 27

A ___device has the ability to produce a voltage in the presence of light.

Answer 27

Photo voltaic

Question 28

Regardless of the way an SCR is shut down, the process is called_____.

Answer 28

Commutation

Question 29

An SCR stays off until a point called ____ breakover voltage is reached.

Answer 29

Forward

Question 30

When light strikes a transparent surface, it is divided into 2 beams....

Answer 30

reflective and refractive

Question 31

During testing, a forward biased P-N junction will indicate....

Answer 31

Low resistance

Question 32

A ____ is a device that receives a small signal and produces a larger signal.

Answer 32

Amplifier

Question 33

The principle operation of fiber optic cable

Answer 33

Total internal reflection

Question 34

List 5 steps for processes involved in a complete power supply system.

Answer 34

a. Convert to AC power b. Rectify ac to pulsating DC c. Filter DC d. regulate output e. divide output

Question 35

The main difference between LED and LCD is....

Answer 35

LEDS emit light, LCDs control light

Question 36

The primary function of an optocopuler is to provide electrical____ between inputs and outputs.

Answer 36

Isolation

Question 37

Which type of fiber optic cable offers the highest data transmission speed?

Answer 37

Single Mode

Question 38

Name 3 parts of fiber optic cable

Answer 38

1. Core 2. Cladding 3. Buffer

Question 39

Name 2 advantages of photo operated devices

Answer 39

Quick switch time, | No contact bounce

Question 40

List 3 ways to prevent transistor thermal instability

Answer 40

1. heat sink 2. Feedback current 3. Voltage divider

Question 41

4 advantages of fiber optic cable over conventional copper cable

Answer 41

1. Lighter 2. No interference 3. Data security 4. Faster and larger data capacity

Question 42

Why is lower impedance in a transformer a concern?

Answer 42

Higher current flows when a short circuit happens

Question 43

A buck boost is typically used to change voltage between ___ and ___ volts.

Answer 43

5 and 25

Question 44

Harmonics create problems by causing excess ____ in a transformer.

Answer 44

Heat

Question 45

If frequecy is increased in a parallel RC circuit, the current will ____.

Answer 45

Increase

Question 46

3 ways to guard a transformer

Answer 46

Elevation, barrier, partitions

Question 47

Two functions served by the liquid in a liquid-immersed transformer

Answer 47

1. Keeps it cool (temperature) 2. Insulated 3. Dielectric

Question 48

Two limitations of auto transformers

Answer 48

1. Low impedance | 2. No isolation between windings

Question 49

List 4 ways to maintain a transformer (things to look for)

Answer 49

a. Loose nuts and bolts b. Coil damage c. Loose lamination d. build up of dust

Question 50

List the four ways diodes can be used in power and signal circuits

Answer 50

a. Logic functions b. As a switch c. Signal mixers d. Radio wave detectors.

Question 51

5 functions of a fire alarm system

Answer 51

1. Early detection 2. Occupant notification 3. Building systems management 4. Emergency control functions 5. Notification of the police department.