Untitled Deck Flashcards
(39 cards)
On an Electrical diagram, what does the symbol S2 indicate?
one double pole switch
What is the main function of the drop relay in a closed circuit security alarm system?
to latch the coil to keep the circuit in the alarm condition
Which of these detectors uses a microphone?
audio
How many volts should be expected between the red and white conductors on an energized circuit containing black, red, green and white conductors?
120 volts
One ampere is defined as the flow rate current per second of one:
coulomb
Which of the following opens and closes or interrupts the voltage or power?
relay
A television signal is measured in which of the following?
megahertz
Which one of these switching systems places many inter leveled telephone conversations onto one telephone line?
time division multiplexing
According to the Lineman’s and Cableman’s Handbook, what is the advantage of wood distribution poles to concrete poles?
cost
According to the Lineman’s and Cableman’s Handbook, the recommended hole depth for a 50’ wood pole set in soil is at least:
7’
The total opposition to AC in a circuit which includes resistance, inductance and capacitance is called?
electrical impedance
What connection using 3 resistors will provide maximum total resistance?
all 3 resistors in series
A current that leaves its intended path and returns to the source bypassing the load causes the circuit to be:
shorted
When installing a half inch format camera, looking at the building 30’ away, and it is 18’ in height and 22’ wide, what is the mm lens size that is required?
8 mm
What is the benefit of a covert CCTV system over an overt system?
catch a repeated offender
On a screen, what will give you the greatest number of views?
multiplexer
What is a conductor’s insulation rating based on?
Circuit voltage
Which of the following affects the resistance of a conductor?
material
What type of output is preferred when selecting an amplifier for a 5 speaker public address system install?
ease of matching impedance
Windings in a transformer go around a:
Core
Cable TV coax can be tested by using what?
digital multimeter
What does CCTV stand for?
Closed circuit television
What is the maximum bandwidth of a standard television channel?
8 mhz
A three phase system has no voltage to the neutral load. What is the minimum size neutral needed?
No neutral needed
