Unit 12 Flashcards
Continually and rapidly reversing current 
Alternating current
Protects the circuit from an overload
Circuit breaker
Device used to measure resistance
Ohmmeter
Component that is neither a conductor or insulator, but a partial conductor
Semiconductors
Coil of wire wrapped around an iron core that induces a current to another coil of wire, wrapped around the same iron core
Transformer
Unit of power
Watts
Smallest amount of a substance that can exist
Atom
Used to measure current without breaking a circuit to install the meter
Clamp on meter
Amount of charge that can be stored
Capacitance
When an atom has more electrons than protons
Negative charge
Total voltage is applied across each resistance. Current is divided between the different loads, and total current is equal to the sum of the current in each branch. Total resistance is less than the value of the smallest resistance.
Parallel circuit
Used to measure current in a circuit
Ammeter
Materials with a few electrons in the outer orbit, such as gold, silver, copper and aluminum
Conductor
Has a negative charge and travels around the nucleus in orbits or shells
Electron
Total effect of resistance in a circuit consist of pure resistance, inductive, reactants, and capacitive reactants
Impedance
A resistor that is sensitive to temperature
Thermistor
A force causing a magnetic field to attract ferrous materials, or where light poles of a magnet repel, and unlike poles, attract each other
Magnetism
May be used as a switch or a device to amplify an electrical signal
Transistor
Voltage is divided across the different resistances. Total current flows through each resistance or load. Resistances are added together to obtain total resistance.
Series circuit
Device that allows heat to be dissipated into the surrounding air
Heat sink
T/F
In a capacitive circuit, volt lags current
True
T/F
Total resistance of a parallel circuit is less than the value of the smallest resistance
True
T/F
Current in a series circuit is the same, regardless of where it is measured
True
T/F
In a pure resistive circuit, voltage lead current
False
T/F
If wire is wound into a coil, and a circuit is passed through it, the coil, carrying an electrical circuit is called a solenoid/electromagnet
True
T/F
Electrons flow from positive to negative in a direct current circuit (DC)
False
T/F
Inductive loads, primarily generate a magnetic field, whereas resistive load generate light and or heat
True
T/F
Lightbulbs in a serious circuit will all have the same bright, regardless of the resistance, and each lightbulb
False
T/F
As resistance in a circuit increases, current decreases
True
T/F
A rectifier is used to change AC current into DC current
True
The full load amperage (FLA) reading on a fan motor data plate is 1.5A. What is the lock rotor amperage (LRA) for the fan motor? 
7.5A. Divide LRA by 5 to get FLA
The proper way to discharge a capacitor before testing it is to use a resistor that has a resistance of _______ Kohms and rated for __________watts
20K ohms ; 5watts
How are the three terminals on a dual capacitor marked?
Common, herm, fan
As temperature in a wire increases, resistance _____________.
Increases
What would the voltage in a DC circuit be if there were a current flow of .5 A and a load resistance of 50 ohms?
25 volts.
Draw the electrical symbol for a temperature switch that closes on the rise, commonly used and a cooling thermostat
Draw the electrical symbol for a pressure switch in a normally closed position (N.C)
Draw the electrical symbol for an air core transformer
