Basic Electricity

.535 Millivolts

.535V is

Output device

A motor is a type of electrical ___________________.

5.5Ω

A parallel circuit has 3 resistors. R1=10Ω, R2=20Ω, and R3=30Ω. What is the total resistance of the circuit?

14.85A

Find the current. 208 Volts, 14Ω

18.5Ω

Find the resistance. 13 Volts, 0.7 Amps

132.4Ω

Find the total inductive reactance in a parallel circuit where XL1=940Ω, XL2=231. and XL3=464Ω.

71.4

Find the voltage. Resistance is 17Ω and current is 4.2.

Parallel

In a __________________ circuit, the voltage available to each branch is equal to the source voltage.

Autotransfomer

Only has one coil for both primary and secondary

Voltage

Potential difference refers to _____________________.

Watts

Power is measured in ________________________.

14.4 Amps

What is the current?

To resist changes in current flow

What is the purpose of an inductor?

Yes - but the circuit will operate with reduced current

Will a parallel circuit operate if one of its branches has an open?

.625

What is the total resistance?

Farad

What is the unit of measurement for capacitance?

Henry's

What is the unit of measurement for inductance?

1,000,000 - Mega

What is the value of the prefix M?

1,000

What is the value of the prefix k?

1/1000th - Milli

What is the value of the prefix m?

1/1,000,000th - Micro

What is the value of the prefix µ?

1.5V

What is the voltage drop across each lamp? (C batteries are 1.5V)

Circuit breaker

What is this symbol?

Run capacitor

What is used to continuously adjust current or phase shift to a motors windings in an effort to optimize the motor's torque and efficiency performance?

Parallel

What type of circuit is this?

Wye

What type of circuit is this?

Variable Resistor

What type of resistor can be adjusted?

Alexandro Volta

Who invented the battery?

Thomas Edison

Who invented the light bulb?

Andre Ampere - Founder of amperage

Who is this?

George Simon Ohm

Who is this?

Nikola Tesla - Founder of AC Current

Who is this?

Thomas Edison - Invented the light bulb

Who is this?

Thomas Edison - Edison was a proponent of DC current instead of AC current

Who was Tesla's rival?

Start windings

Which type of windings draw heavy current at startup on a motor?

Start windings

Which windings on a single phase motor are pulled out of the circuit by a centrifugal switch after the motor is running?

Nikola Tesla

Who invented AC electricity?

True

(T/F) A method of troubleshooting a parallel circuit to find a short is to connect an ohmmeter across the main line with the power turned off.

1. Lighting 2. Volume knob 3. Television controls

3 Applications of a variable resistor

1. Commercial building lighting 2. Switch controlled outlets 3. Ceiling fan controls

3 examples of combination circuits

1. Solenoid 2. Relay 3. Motor

3 examples of electromagnetic devices

5,000,000

5Mega Ohms is equivalent to how many Ohms?

8 volts

A 12 volt series circuit has a 100Ω resistor and a 200Ω resistor. What is the voltage drop across the 200Ω resistor?

Bad

A SPST switch reads resistance of 000 while in the off position. Is the switch good or bad?

Short Circuit

A _____________ in the branch of a parallel circuit will cause excess current to flow.

Battery

A _____________ is a common source of DC current.

Short circuit

A ______________ in the branch of a parallel circuit can cause a short circuit across the power supply.

12 volts

A battery gives 12 volts to a 17Ω lamp. What voltage will it give to a 20Ω lamp?

Yes - Because 370 volts is the peak voltage rating of the capacitor.

A capacitor has a voltage rating of 370 volts. Will it work on a 208 circuit?

Equal

A capacitor in a DC circuit will charge to a voltage __________ to the source voltage.

direct short

A circuit breaker that trips immediately indicates a __________________________.

2637.6

A circuit in the US has inductance of 7 henries. What is the Inductive reactance?

40Ω

A series circuit has a 10Ω resistor, a 20Ω resistor, and a 30Ω resistor. The 20Ω resistor is shorted from one side to the other and is bypassed. What is the resistance total?

Parallel

A short circuit in a ___________ circuit can damage or destroy the power supply.

cause an excessive amount of current to flow.

A short circuit in a branch of a parallel circuit will

120 VAC (Volts Alternating Current)

A standard household wall outlet has a voltage supply of __________ volts.

Solid-state

A time-delay relay that uses an RC timing circuit is called a(n) _________________ time-delay relay

176.75 Volts

A wall outlet read 125 volts. What is the peak voltage?

Bad

A wire reads a resistance of "O.L". Is the wire good or bad?

Bad

A wire reads resistance of "I". Is the wire good or bad?

Alternating Current

AC

24 volts

According to Kirchhoff's voltage law for series circuits, if a series circuit has a resistor with a voltage drop of 5 volts and another resistor with a voltage drop of 19 volts, what is the source voltage?

ion

An atom gains an electron. What is the atom called now.

Current Flow

An inductor is a coil that opposes changes in ________________.

Circuit

Any path that allows the electrons to leave the power supply an return to the power supply is called a

Schematic diagram

Documentation that is helpful in troubleshooting a circuit.

Switch

Basic electrical component to open and close a circuit.

Off

Before "ohming" out a component, make sure the voltage is turned _______________.

isolated

Before checking continuity on a component, make sure the component is ___________________ from the rest of the circuit.

Farads

Capacitance is measured in ______________.

Farads

Capacitance is measured in _____________________.

apparent resistance to AC by a capacitor.

Capacitive reactance is

Filter out the unwanted AC voltage

Capacitors are commonly used in DC power supplies to _________________________.

Voltage Divider

Circuit that uses resistors to drop source voltage to a lower voltage

Inductor

Coil that opposes any change in current flow

Control Transformer

Commonly used to reduce line voltages of 240VAC or 480VAC to 120VAC

Parallel

Components wired in parallel in a series-parallel circuit will display characteristics of a _______________ circuit.

Amps

Current is measured in _______________________.

Direct Current

DC

Transformer

Device that transforms one AC voltage to another AC voltage

Electromotive Force

EMF

60Ω

Each light has 20Ω of resistance. What is the total resistance of this circuit.

least resistance

Electricity follows the path of ________________.

Volts

Electromotive Force is measured in _________________.

Pushbutton switch

Manually operated switch where you push a button

XLT=1/(1/XL1 + 1/XL2 + 1/XL3...)

Formula for Total Parallel Inductive Reactance

XCT=XC1 + XC2 + XC3...

Formula for calculating Total Series Capacitive Reactance.

LT=L1 + L2 + L3...

Formula for calculating Total Series Inductance

CT=C1 + C2 + C3...

Formula for calculating total parallel capacitance.

Hertz or Hz

Frequency is measured in _______________.

Rheostat

High voltage variable resistor

Divide input voltage by the turns ratio

How do you calculate the output voltage of a transformer?

1. Disconnect the power supply 2. Look for visible signs of damage 3. Connect an ohmmeter across the main line

How do you check for a short in a parallel circuit?

1. Verify primary coil continuity 2. Verify secondary coil continuity 3. Verify no continuity between primary and secondary coils 4. Verify no continuity between either coil and ground

How do you troubleshoot a transformer?

5VAC

How do you write 5 volts AC

5V or 5VDC

How do you write 5 volts DC?

127 volts

If the peak voltage in a circuit is 180 volts, what is the RMS value?

25%

If you connect a 240 volt heating element up to 208 volts, how much decrease in efficiency will you have?

Resistance will suddenly rise

If your meter is set to ohms and connected across the main line, what will happen if you disconnect the branch that contains a short?

Actual

In __________________ current flow theory electrons flow from negative to positive.

Conventional

In __________________ current flow theory electrons flow from positive to negative.

A

In a 3 phase breaker panel, what phase is the 4th breaker down on the right.

Selector switch

Manually operated switch where you select a position and turn the switch knob to it.

Insulator

Material that does not conduct electricity very well.

10 gauge

In your service van you have 12 gauge wire and 10 gauge wire. Which is the bigger gauge of wire?

DC

Inductance affects a ____________ circuit only when the current is first turned on, off, or there is a change in load resistance.

Henrys

Inductance is measured in ______________________.

No

Is a ceiling fan/lights an example of a series circuit?

Yes

Is a commercial buildings lighting systems an example of a combination circuit?

Yes

Is an electrical outlet controlled by a switch an example of a series-parallel circuit?

1/10th

It only takes _________________ of an amp to kill you.

Potentiometer

Low voltage variable resistor

Knife switch

Manually operated switch used when visual confirmation of the switch state is needed.

AC

Most of the electrical power produced in the world is _________.

It went down.

My amperage went up. What happened to my resistance?

Electrolytic, Non-Polarized, and Variable

Name 3 types of capacitors.

Actual current theory

Name the theory. Electrons flow from negative to positive.

Conventional current theory

Name the theory. Electrons flow from positive to negative.

Series Capacitance

Name this formula.

Variable resistor

Name this symbol.

Schematic diagram

Represents components with standard symbols

Ohms

Resistance is measured in ____________________.

carbon

Resistors are typically made from ____________________.

Metal

Run capacitors typically have a ____________ case.

Single pole single throw

SPST stands for

single

Start capacitors are used to start some ______________ phase motors.

Bleed Resistor

Start capacitors typically have a _________________ to drain off voltage when it is not being used.

Common

Switch contact that incoming power is connected to.

Normally open

Switch contacts which are closed when acted upon by an operator.

Normally closed

Switch contacts which are opened when acted upon by an operator.

60

The AC electricity produced in the U.S cycles ___________ times per second.

Capacitive Reactance

The apparent resistance to AC by a capacitor is called _____________________.

Primary Winding

The current load of a transformer is the current drawn by the ___________________.

Positive

The highest potential of current flow in conventional current theory is the ___________ terminal.

L

The letter that represents inductance in formulas is _____________.

10

The load resistance value in a voltage divider should be at least ___________ times greater than the resistance value of the voltage divider resistor.

Negative

The lowest potential of current flow in conventional current theory is the ___________ terminal.

an open.

The most common circuit fault is ....

Voltage

The potential difference between two points in a circuit is called ___________________.

power in = power out = loss

The power relationship on a transformer states that

Power In = Power Out + Loss

The power relationship on a transformer states that _________________________.

Inductive reactance

The resistance provided by an inductor in an AC circuit is called __________________.

True

True or false. Current flows through the neutral line when a machine is operating.

True

True or false: Nickel is a good conductor of electricity.

False

True or false: Rubber is a good conductor of electricity.

True

True or false: Silver is a good conductor of electricity.

Power Supply

To maintain a constant voltage output under varying loads requires a constant voltage ______________.

Distribution Transformer

Transformer with a center tap on the secondary

volt amperes

Transformers are usually rated in units called

Volt Amperes

Transformers are usually rated in units called _____________.

Mutual inductance

Transformers operated off the principle of ___________.

Voltage divider

Using resistors in a circuit to produce a voltage lower than the source voltage is called a ___________________ circuit.

1. Excessive current to flow 2. Damage or destruction of the power supply 3. A short circuit across the power supply

What can a short circuit in a parallel branch cause?

Thermal circuit breakers

What do the symbols on the right side of this disconnect represent?

The rest of the circuit to operate with a reduced current

What does an open in a branch of a parallel circuit cause?

micro

What does the symbol µ represent?

60 Hertz

What is the Hertz in the United States?

3.6 amps per phase

What is the amperage draw per phase on a 240 volt 3-phase 1500 watt motor?

12 gauge wire

You are pulling a new circuit that connects to a 20 amp breaker. What size of wire do you need?

10 gauge

You are pulling a new circuit that connects to a 30 amp breaker. What size of wire do you need?

open.

You have an ohmmeter connected across the main line of a parallel circuit. You disconnect one branch and there is no change in ohms. You have discovered the branch with a(n)

AC or Alternating

_____________ current flows alternately in one direction and then the other.

Current

______________ delivers electrical power to its point of use.

Electricity

___________________ is the flow of electrons in a conductor.

Direct Current

______________________ electricity flows in only one direction.