Flashcards in HVAC electrical test Deck (85)
What is current flow?
The flow of electrons in the circuit.
What is impedance?
Opposition to alternating current flow?
Like charges will..
Repel each other.
Any material that will readily release electrons is called?
The symbol for current is?
Electricity can produce
Heat, light, magnetism
The safety ground conductor is usually color coded?
An electron has?
A negative charge
What is resistance?
Opposition to current flow
How many watts of power are used by a heater operating at 460 volts and drawing 5 amps?
What type of meter uses it's own battery?
In electrical wiring, a black colored wire usually indicates....
The hot conductor
How are fuses sized?
Amps and volts
Two 120 volt motors are wired in a series, one is a 60 watt motor, the other is a 4 watt motor. The result would be...?
Neither motor would operate normally
What would be the result of three defrost heaters, each 12.5 ohms, wired in a series to a 115 volt power supply, it the heaters were to supply a 360 watt heating load?
Heaters do not energize
What is generally considered to be the maximum allowable (+ or -) supply voltage variation?
Capacitors are rated in...
Microfarads and volts
When testing a capacitor with an analog ohmmeter, the needle on the meter should..
Deflect towards zero then return to infinite reading.
What is the term used to describe the output side of a transformer?
One horsepower is equal to _______ watts.
How much resistance must be placed in a 110 volt circuit in order to limit the current to 2 amps?
A. 55 ohms
B. 110 ohms
C. 30 ohms
D. None of the above
A parallel circuit contains a 18 ohm and a 9 ohm resistor. The total resistance equals...
A. 6 ohms
B. 27 ohms
C. 8 ohms
D. 10 ohms
In a series circuit, the voltage drop across each resistance (load) will...
A. Always add up to equal the source voltage.
B. Depend on the value of each resistor.
C. Depend on the current flow in the circuit.
D. All of the above
All the above
The total resistance of a parallel circuit will be...
A. The sum of all resistances
B. Equal to the largest resistance
C. Equal to the smallest resistance
D. Less than the smallest resistance.
Less than the smallest resistance
Which of the following statements about current is true?
A. Current flow is the same as voltage
B. Current flow will increase when voltage increases.
C. Current flow will increase when resistance increases.
D. Current flow will decrease when voltage increases.
Current flow will increase when voltage increases.
When resistors are wired in parallel...
A. The current through any one resistor will be the same as the total circuit current.
B. The voltage drop across each resistor will be the same as the applied source voltage.
C. The voltage drop across each resistor will depend on the value of each resistor.
D. The total resistance is determined by adding the values of each resistor.
The voltage drop across each resistor will be the same as the applied source voltage.
Which of the following is equal to 2.1 KV?
A. 21 volts
B. 210 volts
C. 2100 volts
D. 21000 volts
Which of the following is equal to 100 milliamps?
A. 1.0 amperes
B. 10.0 amperes
C. 0.10 amperes
D. 0.01 amperes
(each amp is equal to 1000 milliamps)
A capacitor analyzer is designed to..
A. Read power factor percentage
B. Diagnose an open or shorted capacitor.
C. Read the microfarad rating of a capacitor.
D. All of the above
Read the microfarad rating of a capacitor