3rd year final Flashcards
The process by which impurities are added to a semiconducting material to change its electric characteristics is called.
Doping
When voltage is applied to a diode, the action occuring in the ____ region either blocks current flow or passes current.
Depletion
Capacitive filter elements can be used for smoothing the output _____ across the load.
voltage
A diode will conduct normal current when the ___ is positive with respect to the_____.
Anode, cathode
The ____ converts AC to a pulsating DC voltage.
Rectifier
What determines the load polarity of a power supply the that converts AC to DC?
diode
P-Type semiconductors have been doped with a_____ of free electrons.
Deficiency
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 _____.
Shorted
The primary purpose of a Zener diode is to act as a ______.
Voltage regulator
List 4 ways that Diodes can be used in signal and power circuits.
- Detectors of Radio Waces
- Logic Functions
- Switching
- Signal mixers
Regardless of the way an SCR is shut down, the process is called _____.
Commutation
An SCR stays off until a point called ____ breakover voltage is reached.
Forward
A ____ device has the ability to produce a voltage in the presence of light.
Photovoltaic
The first automatic fire alarm detection device was a _____.
Fuseable link heat detector
A_____switch is not a supervisory switch.
a.Room temp b.Vane type flow C.Valve tamper
D.Water Level
B.Vane type flow
The most appropriate detection for an atrium is a ____.
Projected beam smoke detector
A short circuit on a fire alarm initiating device circuit causes a ____ signal.
Trouble
The minimum sound pressure level for an audible fire alarm notification appliance at the pillow in a sleeping area is _____ dBA.
75
A firestopping material that expands when heated is referred to as ______.
Intumescent
What is the maximum distance that visible notification appliances must be located from the end of a corridor?
15 ft
There are five primary functions of a fire alarm system. Name Four
- Early Detection
- Occupant notification
- Safely control functions
- Building systems management
Non power-limited fire alarm systems have a maximum operating voltage of ____volts.
600
Upon detection of a trouble condition, fire alarm system controls must initiate a trouble signal within ____ seconds.
200
Name 3 types of supervising stations systems
- Central
- Remote
- Proprietary
List the four emergency control functions that may be controlled by a fire alarm system.
- Elevator recall
- HVAC shutdown
- Door unlocking
- Stairway pressurization
Name the three basic parts of fire protection
- Detection
- Containment
- Suppression
A ___device has the ability to produce a voltage in the presence of light.
Photo voltaic
Regardless of the way an SCR is shut down, the process is called_____.
Commutation
An SCR stays off until a point called ____ breakover voltage is reached.
Forward
When light strikes a transparent surface, it is divided into 2 beams….
reflective and refractive
During testing, a forward biased P-N junction will indicate….
Low resistance
A ____ is a device that receives a small signal and produces a larger signal.
Amplifier
The principle operation of fiber optic cable
Total internal reflection
List 5 steps for processes involved in a complete power supply system.
a. Convert to AC power
b. Rectify ac to pulsating DC
c. Filter DC
d. regulate output
e. divide output
The main difference between LED and LCD is….
LEDS emit light, LCDs control light
The primary function of an optocopuler is to provide electrical____ between inputs and outputs.
Isolation
Which type of fiber optic cable offers the highest data transmission speed?
Single Mode
Name 3 parts of fiber optic cable
- Core
- Cladding
- Buffer
Name 2 advantages of photo operated devices
Quick switch time,
No contact bounce
List 3 ways to prevent transistor thermal instability
- heat sink
- Feedback current
- Voltage divider
4 advantages of fiber optic cable over conventional copper cable
- Lighter
- No interference
- Data security
- Faster and larger data capacity
Why is lower impedance in a transformer a concern?
Higher current flows when a short circuit happens
A buck boost is typically used to change voltage between ___ and ___ volts.
5 and 25
Harmonics create problems by causing excess ____ in a transformer.
Heat
If frequecy is increased in a parallel RC circuit, the current will ____.
Increase
3 ways to guard a transformer
Elevation, barrier, partitions
Two functions served by the liquid in a liquid-immersed transformer
- Keeps it cool (temperature)
- Insulated
- Dielectric
Two limitations of auto transformers
- Low impedance
2. No isolation between windings
List 4 ways to maintain a transformer (things to look for)
a. Loose nuts and bolts
b. Coil damage
c. Loose lamination
d. build up of dust
List the four ways diodes can be used in power and signal circuits
a. Logic functions
b. As a switch
c. Signal mixers
d. Radio wave detectors.
5 functions of a fire alarm system
- Early detection
- Occupant notification
- Building systems management
- Emergency control functions
- Notification of the police department.
