B2U1 Electrical Theory Flashcards
What is a compound?
, Two or more different elements chemically joined together.
What three parts make up an atom?
(1) Proton.
(2) Neutron.
(3) Electron.
What is a free electron?
An electron located in the valence shell
What occurs when an atom becomes unbalanced?
Ionization.
What is current?
The flow of electrons.
What are the factors that affect the amount of resistance?
(1) Type of material.
(2) The length.
(3) The cross-sectional area.
(4) The temperature of the conductor.
What is a characteristic of AC?
AC continually changes magnitude and occasionally changes direction.
What does Ohm’s Law describe?
The relationship between voltage, current, and resistance.
What is Ohm’s Law?
A relationship, where current is inversely proportional to voltage and directly proportional to resistance.
What is the most common power source in a DC circuit?
A battery.
What is the unit of resistance of a circuit?
The component that a circuit operates.
What determines the amperage it will hold before the temperature rises enough to melt the wire in a fuse?
The size of the fuse wire.
What do grounds protect should the circuit have problems?
Personnel in the area as well as the equipment.
What are DC series circuits?
Circuits with only one path for electron flow through two or more units of resistance.
What is an easy way to remember the characteristics of a series circuit?
Sum, same, sum, sum.
What are parallel circuits?
Circuits that have more than one path for electron flow with only one resistor in each leg of the circuit.
What are the methods to calculate the total resistance in a parallel circuit?
Product over sum, reciprocal, and equal resistance methods.
What is an easy way to remember the characteristics of a parallel circuit?
Same, sum, smaller, sum.
What are series-parallel circuits?
More than one path for current to flow but have at least one resistor that receives the total circuit current passing through it.
What are combination circuits?
Similar to series-parallel circuits except the series resistor does not carry the full circuit current.
What is an electrical cycle?
A complete series of events that begin and end at the same point.
What do the two lines on the sine wave graph represent?
(1) Magnitude.
(2) Time.
What does the frequency of electricity refer to?
The number of occurrences of a complete series of events over a specified time.
What is the effective value of voltage?
The percentage of peak voltage it takes to produce the same amount of work as a DC circuit.
What type of household appliances have inductors?
Refrigerators. Fans.
Vacuum cleaners. Blenders.
Since inductance is the characteristic of an AC electrical circuit that contains an inductor, what does it cause?
An opposition to any CHANGE in current flow
What two things determine the extent of the opposition in an inductive circuit?
(1) The frequency of the applied voltage.
(2) the amount of inductance that is present in the circuit.
What typically makes up this core of a transformer because of the ability to improve magnetic fields?
Soft Iron
What do transformers use to produce voltage on the secondary coil?
Mutual Induction
How is a capacitor constructed?
Two plates of conductive material separated by an insulating material called dielectric.
Since capacitance is the property of a capacitor, what does it cause in a circuit?
An opposition to any CHANGE in the value of voltage.
What does the mnemonic ELI the ICEman spell out for you?
What phase shift takes place when you work with reactive circ
What is true power?
All of the power used in a circuit.
What is reactive power?
The power created by inductance or capacitance.
What is apparent power?
The power you think you are providing from your power source if you look at your voltage and current.
What does a P-type material, called the anode, have a concentration of?
Holes
How should you connect a battery to a diode to get a forward bias connection?
With the negative side of a battery connects to the cathode and the positive side of the battery connects to the anode.
How does current flow in a diode?
Only flows in one direction.
What is a rectifier?
A device that changes AC into DC.
How many diodes does a three-phase bridge rectifier have?
6
What are the four basic types of wiring diagrams used in the Power Production career field?
One-line, schematic, connection, and inter-connection diagrams.
What type of diagram is most useful when troubleshooting equipment malfunctions?
A schematic diagram.
Explain what each of the letters and numbers in wire X130A12 identify.
X identifies the circuit is an AC circuit, 130 is the circuit number, A is the circuit progression letter and 12 is the wire gauge (size).
List the three rules of circuit tracing.
Use the technical manual to understand the circuit operation, identify all circuit components on the diagram by circling or highlighting and trace circuit as you read the circuit description.
Everything in the universe is made up of
a. matter.
b. electrons.
c. compounds.
d. valence shells.
A. Matter
What is the smallest unit a compound can be broken down into without changing characteristics of the compound?
a. Proton.
b. Nucleus.
c. Molecule.
d. Compound.
B. Molecule
What is the purest part of a substance that can be broken down and retains its properties as that element?
a. Element.
b. Nucleus.
c. Electron.
d. Compound.
A. element
What are the three parts of an atom?
a. Proton, nucleus, and neutron.
b. Proton, neutron, and electron.
c. Nucleus, proton, and electron.
d. Nucleus, electron, and neutron.
B. Proton, neutron, electron
How many free electrons do conductors have in the valence shell?
a. 1 to 3.
b. 4.
c. 5 to 8.
d. 9 or more.
A. 1 to 3
In contrast to good conductors, we consider substances that have how many free electrons to be insulators?
a. Between 1 and 3.
b. Between 3 and 5.
c. Between 5 to 8.
d. 9 or more.
C. Between 5 to 8
Semiconductors are not good conductors or insulators and are made of substances that have how many free electrons?
a. 3.
b. 4.
c. 8.
d. 9 or more.
B. 4
What symbol do we commonly use to represent resistance?
a. Roman letter £ (lira).
b. Greek letter Δ (delta).
c. Roman letter ψ (wye).
d. Greek letter Ω (omega).
d. Greek letter Ω (omega).
When it comes to resistance in a piece of wire, what does a smaller surface area cause?
a. Increased power.
b. Lower resistance.
c. Decreased power.
d. Higher resistance
B. Lower Resistance
What type of voltage normally maintains the same magnitude, but may vary?
a. Alternating current (AC).
b. Direct current (DC).
c. Apparent power.
d. Reactive power.
B. Direct Current (DC)
What type of voltage continually changes magnitude and occasionally changes direction?
a. Alternating current (AC).
b. Direct current (DC).
c. Apparent power.
d. Reactive power.
A. Alternating Current (AC)
Ohm’s Law describes the relationship between
a. voltage, current, and power.
b. resistance, current, and power.
c. resistance, voltage, and power.
d. voltage, current, and resistance.
D. voltage, current, and resistance.
What is the relationship of current based on Ohm’s Law?
a. Directly proportional to power and directly proportional to voltage.
b. Inversely proportional to power and directly proportional to resistance.
c. Directly proportional to voltage and inversely proportional to resistance.
d. Inversely proportional to voltage and directly proportional to resistance.
d. Inversely proportional to voltage and directly proportional to resistance.
What device allows you to control a direct current (DC) circuit manually?
a. Relay.
b. Switch.
c. Rectifier.
d. Transformer.
B. Switch
Which direct current (DC) circuits have only one path for electron flow?
a. Series.
b. Simple.
c. Parallel.
d. Series-parallel.
A. Series
What method of calculating total resistance of a parallel circuit only works when calculating two resistors?
a. Reciprocal method.
b. Equal resistor method.
c. Product over sum method.
d. Adding all resistors together.
C. Product over sum method
What type of direct current (DC) circuit has more than one path for current to flow but have at least one resistor that receives the total circuit current passing through it?
a. Series circuit.
b. Simple circuit.
c. Parallel circuit.
d. Series-parallel circuit.
D. Series-Parallel circuit
What is the characteristic for total power in a series parallel circuit?
a. Product of the power at the individual resistors.
b. Less than the lowest power value at a resistor.
c. Sum of the power at each individual resistor.
d. The same throughout the circuit.
c. Sum of the power at each individual resistor.
What type of circuit typically has a parallel circuit with one or more legs having series portions?
a. Series circuit.
b. Parallel circuit.
c. Combination circuit.
d. Series parallel circuit.
C. Combination circuit
When you hear about the frequency of electricity, it refers to the number of complete cycles that occur in
a. 1 second.
b. 10 seconds.
c. 30 seconds.
d. 1 minute.
A. 1 second
In an alternating current (AC) voltage signal, how many peaks does each cycle have?
a. 1.
b. 2.
c. 3.
d. 4.
B. 2
What component does a magnetic field have little to no influence on?
a. Resistors.
b. Inductors.
c. Capacitors.
d. Transformers
A. Resistors
A good example of a use for a variable resistor is a
a. winding for an electrical motor.
b. rectifier for a battery charger.
c. dimmer switch for a light.
d. coil for a power supply.
C. Dimmer switch for a light
What do we call the induced voltage that moves in the opposite direction as the applied voltage in an inductor?
a. Cross currents.
b. Mutual induction.
c. Induced resistance.
d. Counter electromotive force (EMF).
D. Counter electromotive force (EMF)
What alternating current (AC) characteristic causes an opposition to any CHANGE in current flow?
a. Capacitance.
b. Inductance.
c. Resistance.
d. Reactance.
B. Inductance
What component may increase or decrease voltage in a circuit?
a. Inductor.
b. Capacitor.
c. Oscillator.
d. Transformer.
D. Transformer
If the secondary coil of a transformer has less coil turns, what does the transformer do to meet circuit needs?
a. Steps the voltage level up.
b. Steps the voltage level down.
c. Maintains the voltage level the same.
d. Isolates the circuit from other components.
B. Steps the voltage level down
If the secondary coil of a transformer has more coil turns, what does the transformer do to meet circuit needs?
a. Steps the voltage level up.
b. Steps the voltage level down.
c. Maintains the voltage level the same.
d. Isolates the circuit from other components.
A. Steps the voltage level up
What type of transformer only uses a secondary coil?
a. Potential.
b. Isolation.
c. Current.
d. Power.
C. Current
What is the insulating material called that separates the two plates of conductive material in a capacitor?
a. Carbon.
b. Dielectric.
c. Sulfuric acid.
d. N-type materi
B. Dielectric
What alternating current (AC) characteristic causes an opposition to any CHANGE in the value of voltage?
a. Capacitance.
b. Inductance.
c. Resistance.
d. Reactance
A. Capacitance.
NOTE:
Capacitance is for voltage
Inductance is for current
Since most of the capacitors you will see have a rating much lower than one farad, what do we refer to these as, represented by μf?
a. Microfarad.
b. Megafarad.
c. Minifarad.
d. Milifarad.
A. Microfarad
Which mnemonic spells out the phase shift in an alternating current (AC) circuit?
a. ROY G BIV.
b. ALI the ACE.
c. ROE the EAR.
d. ELI the ICEman.
D. ELI the ICEman
What do we call the power created by inductance or capacitance?
a. Apparent power.
b. Reactive power.
c. Evident power.
d. True powe
B. Reactive power
What is the bias of a diode when we connect the positive terminal of the battery to the P- type material and the negative terminal of the battery to the N-type material?
a. Forward.
b. Cathode.
c. Reverse.
d. Anode.
A. Forward
How much resistance does a diode offer to the current flow when the power source connects in the forward bias direction?
a. None.
b. Low.
c. Moderate.
d. High.
B. Low
In reference to reverse bias, what happens when the majority carriers move outward allowing the barrier voltage to increase?
a. Decrease in the depletion region.
b. Increase in the depletion region.
c. Decrease in the forbidden band.
d. Increase in the forbidden band
B. Increase in the depletion region
What are the four basic types of wiring diagrams used in the power production field?
a. One-line, schematic, connection, and interconnection diagrams.
b. One-line, schematic, connection, and troubleshooting diagrams.
c. One-line, connection, troubleshooting, and interconnection diagrams.
d. Schematic, connection, troubleshooting, and interconnection diagrams.
a. One-line, schematic, connection, and interconnection diagrams.
Which diagram shows the connection of an installation or its component devices and equipment?
a. One-line.
b. Schematic.
c. Connection.
d. Interconnection.
C. Connection
Which diagram provides complete wire numbers, plug and jack pin numbers, and cannon plug numbers required to completely extract and troubleshoot specific circuits?
a. One-line.
b. Schematic.
c. Connection.
d. Interconnection.
C. Connection
What do dot-dash lines mean on an interconnection diagram?
a. Outline of the generator.
b. Outline the panel sections.
c. Sections that work together.
d. Sections that work independent
B. Outline the panel sections
What diagram should include all wire numbers, device code numbers, and area designations?
a. A one-line.
b. A schematic.
c. An extraction.
d. A circuit card.
C. An extraction
Which diagram is the most important of all diagrams because it is your guide through the connection diagram?
a. One-line.
b. Schematic.
c. As-built.
d. Interconnection.
B. Schematic
