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117 Cards in this Set
- Front
- Back
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The ability to utilize all types of communication skills is ____ to the HVACR technician.
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Very Important |
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Itis important to be ____ in filling out service orders so that office staff,other technicians, and customers will know what work you completed on the job
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clear
complete concise |
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When explaining to a customer that you haveadjusted the system charge, what term should you use? |
Refrigerant |
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Listening carefully to what a customer is tellingyou ____.
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can help you diagnose the problem
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When you arrive at a service call and meet thecustomer, you should ____. |
Listen to the customer first,then ask questions
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What is the volume of a room that measures 10 ftby 20 ft with an 8-ft ceiling? |
LxWxH 1,600 ft3 |
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What is the formula for finding CFM requirementsfor a house?
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CFM=SQft x ceiling x air changes /60
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What is the cross-sectional area of a 10-inround metal duct? |
Note: Area of a circle = π x radius^2
79 in2 |
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How do you find velocity pressure of a duct? |
Velocity = 4005 x (thesquare root of velocity pressure
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Customers depend on you to be ____. |
honest loyal patient |
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Before leaving a service call, you should besure to ____. |
Demonstrate system operation anddescribe basic maintenance procedures to the customer.
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What is the advantage of using a tube cutter tocut copper pipe?
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It can cut hard or soft drawn copper It leaves no metal shavings to contaminate the system It produces a clean, square cut |
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Spring-type benders may be used on ____. |
Soft drawn copper
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A flaring tool is used to ____. |
Make a mechanical joint in tubing.
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A swaging tool is used to ____.
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Solder tubing without the use of couplings
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What is one of the advantages of a glass-stemthermometer?
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It is very accurate
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In discussing human comfort, the temperaturemost commonly referred to is ____.
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Dry-bulb
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A sling psychrometer uses two glass-stemthermometers. One measures,______ and the other measures ____. |
Wet-bulb
Dry-bulb |
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A standard refrigeration manifold uses what type of element to measure pressure?
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Bordon tube
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What is the pressure range of a standard-compound gauge on a refrigerant manifold? |
30 in. Hg to 500 psig
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What is the best tool for removing moisture andnon-condensibles from a system before adding refrigerant?
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Vacuum pump
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A vacuum gauge reads pressure in ____. |
Microns
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Which of the following is not a method of leakdetection?
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Moronic
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To prevent the release of refrigerant to the atmosphere while removing it from a system, what type of equipment must be used? |
Recovery machine
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An anemometer uses a small fan blade to measure____.
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Air velocity
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What is one of the advantages of using silverbrazing rods for copper-to-copper joints? |
No flux is required
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“Housekeeping" includes ____. |
Disposal of waste
Fire prevention and protection Proper storage of materials |
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What type of eye protection should you wear when drilling overhead?
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Goggles
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What agency regulates cylinders and chemicalstransported in a service vehicle? |
DOT
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Material safety data sheets ____. |
Contain information about personal protective equipment
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When should oxygen be used in a refrigeration system? |
Never
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Which of the following classifications of fire extinguishers should be used for electrical fires?
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Class C is an electrical fire, extinguishing agent: carbon chemicals, extinguishing agent: foam dioxide
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Which of the following categories could beconsidered a hazardous atmosphere in a confined space?
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Asphyxiating
Flammable Toxic |
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Which of the following best describes anasphyxiating atmosphere?
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Low oxygen level
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If a ladder is placed against a wall that is 20ft tall, what is the proper distance away from the wall for the base of the ladder?
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For every 4ft up the ladder needs to be 1ft out at the bottom
5 ft |
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When using a ladder, you should always ____. |
Maintain three points of contact
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What is one of the most important safety precautions that you can take when working on electrical equipment? |
Disconnect and lock out power before starting unless testing requires the power to be on
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When does a ground fault circuit interrupter open an electric circuit?
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When current travels through a ground path other than the neutral
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Proper lockout/tag out procedures state thatlocks placed on a lockout device may be removed ____.
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Only by the person who installed the locks
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A natural cooling process produced by moistureon the skin changing to low-pressure steam is called ____.
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Evaporation
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During the heating season, human comfort can be enhanced without changing the temperature of the air by ____.
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adding moisture
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During the cooling season, dampers on bypass humidifiers should be ____.
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Completely closed
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All matter can exist as a ____.
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liquid
solid gas |
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Stored energy is called ____ energy.
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Potential
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Heat that you can feel and measure directly witha thermometer is called ____ heat. |
Sensible
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The heat energy change associated with a phase(state) change is called ____ heat.
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Latent
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The amount of heat (Btu) needed to raise the temperate of 1 lb of a substance 1°F is called the ____ heat of the substance.
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Specific
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The latent heat of fusion is the amount of energy required to change 1 lb of a substance from the ____ phase to the ____phase without changing its temperature. |
Liquid, Solid
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At 32°F, 1 lb of ice can be changed to 1 lb of water by adding ____ Btu.
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144 Btu
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At 212°F, 1 lb of water can be changed to 1 lbof steam by adding ____ Btu.
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970 Btu
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When liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added,the vapor is said to be ____.
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Saturated
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When a vapor is heated to a temperature higherthan its saturation point, both the added heat and the temperature above saturation are called ____.
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Superheat
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The process of molecules escaping from the surface of a liquid is called ____. |
Evaporation
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The process of a solid turning directly into a vapor without going through the liquid state is called ____. |
Sublimation
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The continuous movement of molecules within a liquid or gas is called ____ energy.
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Kinetic |
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Enthalpy includes both ____ and ____ heatenergy. |
Latent, Sensible |
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The measurement of the force that gravity exertsis called ____. |
Weight |
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The amount of matter in a substance is called____. |
Mass |
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Weight per unit volume or mass per unit of volume is called ____. |
Density |
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Volume per unit of mass or weight is called____. |
Specific volume |
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Under standard conditions, air weighs approximately ____ lb/ft3. |
0.075 lb/ft3 |
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Convert Fahrenheit temperature Celsius. |
C= (F-32)/1.8 |
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Convert Celsius to Fahrenheit. |
F= (1.8xC) +32 |
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If the absolute temperature of a gas is doubled,under constant pressure the volume will be ____. |
Doubled
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What is the formula to figure the change ofvolume of Air when temperature change is applied?
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Volume is VF=VI (Tf/Ti)
T=F+460 I= Initial F=Final |
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How do you find absolute pressure?
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Gauge pressure + 14.7
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The law that applies to the total pressure exerted by a mixture of gases or vapors is called ____ .
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Dalton's Law
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A coulomb is a charge of ____ electrons. |
6.28 x 10^18
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An ampere is a measurement of ____. |
Electron flow
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Voltage is best described as the ____.
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Force that moves electrons through a circuit
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Current in a circuit is limited by ____. |
Resistance
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A substance that permits the free movement ofelectrons is called a (n) ____.
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Conductor
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Which of the following conductors would have the least resistance?Ashort, large-diameter conductor |
A short, large-diameter conductor
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If the voltage in a circuit is doubled and the resistance remains the same, the current will ____. |
Double
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What is the voltage of a circuit if the resistance is 5Ω and the current is 5 A? |
25 V
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A circuit has a voltage of 10 V and a current of 5 A. What is the resistance? |
2 Ω
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The total resistance of a series circuit is equal to the ____. |
Sum of all the resistances in the circuit
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The total current in a parallel circuit is ____.
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The sum of the currents through the individual paths
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The rate of doing work is called ____.
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Power
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One kilowatt is equal to ____. |
1,000 W U
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The following equations is used to solve for electric power? |
P = E x I
P = I^2 x R P = E^2 / R |
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What is the power in a circuit that has acurrent of 10 and a resistance of 10Ω?
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1 kW
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The voltage induced in each turn of the secondary coil of a transformer is ____.
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The same as the voltage induced per turn of the primary coil
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The load rating of a transformer is stated in ____.
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Volt-Amperes
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An A/C induction motor consists of a stationarypart called the ____ and a rotating part called the ____. |
Stator, Rotor
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What is the synchronous speed of a three-phasemotor that has six poles and is operated on a 60-Hz alternating current? |
1,200 RPM
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How does the power factor of an inductive motoraffect efficiency?
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The lower the power factor, the less efficient the motor is.
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Which of the following single-phase ac motorsdoes not have a start winding?
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Shaded-pole
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A centrifugal switch opens the start winding circuit when a capacitor-start motor reaches approximately ____% of its fullspeed.
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75 to 80%
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A run capacitor is always connected to the ____and ____ terminals. |
Start, Run
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Terminal No. 1 on all potential relays is always connected to the ____. |
Start capacitor
Note: Terminal No. 1 on all potential relays is always connected to the start capacitor. Terminal No. 2 is always connected to the start winding terminal on the motor or compressor. Terminal No. 5 is always connected to the common terminal of the motor or compressor. |
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The coil of a voltage relay is between terminal____ and terminal ____ of the relay. |
2, 5
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What type of ac motor has the highest startingtorque and the greatest efficiency?
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Three-phase
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How many terminals does a dual-voltage three-phase motor have?
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9
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The primary function of any wiring diagram is to____.
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Aid the technician in finding the problem
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How many functions is an individual circuit in acontrol system designed to control?
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One
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The five basic components common to all schematics are a power supply, a path, a load, a legend, and a ____. |
Switch
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The intention of the overall schematic is toshow how the circuit ____. |
Functions
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The type of schematic that provides the most helpful troubleshooting information for the service technician is the ____diagram.
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Ladder
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Devices that consume power and convert it tosome other form of energy, such as motion or heat, are ____.
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Loads
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The normal dividing line for voltage changes ina schematic is the ____. |
Transformer
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The part of the schematic that lists and explains the system components is called the ____.
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Legend
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Relays and contactors are ____ control switches.
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Electrically operated
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A (n) ____ circuit allows the same current toflow through all of the components.
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Series
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A (n) ____ circuit has multiple paths forcurrent flow. |
Parallel
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What types of circuits are primarily used in control and safety applications?
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Series-Parallel
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When testing with a voltmeter, you should place the meter ____. |
In parallel with the circuit being tested
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What does a resistance rating of 0Ω indicate? |
There is a short circuit
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When you use an ohmmeter, the circuit beingmeasured must be ____.
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Isolated from all energy sources
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When you test a switch with an ohmmeter, a reading of ____ indicates that the switch is closed.
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0 Ω
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On all meters, digital and analog, the scaleused should indicate the measurement ____.
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Close to the middle of the range
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When testing across a closed switch in an energized circuit, you should read ____.
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0 V ac
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When using a standard clamp-on ammeter, youshould ____ before taking a reading.
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Make sure that the jaws are closed
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When testing compressor windings, you take thefollowing readings:
C to R: 2 Ω C to S: infinite resistance R to S: infinite resistance What is the diagnosis? |
The start winding is open
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Capacitance meters must be used on capacitors____.
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That have been removed from the circuit
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When testing a thermostat wire that has been removed from the circuit, you measure 0 Ω between red and white. This indicates that ____.
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There is a short
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When testing with an ammeter, you should place the meter ____. |
In series with the circuit being tested
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