Chapter 3: Electricity, Components, and Circuits

Question 1

Electrical current is measured in what unit?

Answer 1

Amperes, amps, or A

Question 2

What is the name for the flow of electrons in an electric circuit?

Answer 2

Current, or I

Question 3

What is the name for a current that flows only in one direction?

Answer 3

Direct Current or DC

Question 4

What is the electrical term for the electromotive force (EMF) that causes electron flow?

Answer 4

Voltage, Volts, or E

Question 5

What is the name for a current that reverses direction on a regular basis?

Answer 5

Alternating Current, or AC

Question 6

What is the unit of electromotive force?

Answer 6

Volts, or V

Question 7

Which instrument would you use to measure electric potential or electromotive force?

Answer 7

Voltmeter, or Multimeter

Question 8

Which instrument is used to measure electric current?

Answer 8

Ammeter, or Multimeter

Question 9

In which type of circuit is current the same through all components?

Answer 9

Series circuit

Question 10

In which type of circuit is voltage the same across all components?

Answer 10

Parallel circuit

Question 11

What happens to current at the junction of two components in series?

Answer 11

The same current flows in each components

Question 12

What happens to current at the function of two components in parallel?

Answer 12

When components are connected in parallel with a source of voltage, the voltage across each is the same as that of the source.

Question 13

What is the voltage across each of two components in series with a voltage source?

Answer 13

When the components are connected in series with the source voltage, the voltage divides between the components, depending on their type and value

Question 14

What is the voltage across each of two components in parallel with a voltage source?

Answer 14

The voltage divides between the components, depending on their type and value

Question 15

What is the correct way to connect a voltmeter to a circuit?

Answer 15

Voltmeters are connected in parallel with or “across” a component or circuit to measure voltage

Question 16

How is a simple ammeter connected to a circuit?

Answer 16

Ammeters are connected in series with a component or circuit to measure current

Question 17

Which of the follow is a good electrical conductor?

Answer 17

Copper

Question 18

Which of the following is a good electrical insulator?

Answer 18

Glass, ceramics, dry wood, paper, most plastics, other non-metals

Question 19

What instrument is used to measure resistance?

Answer 19

Ohmmeter, or Multimeter

Question 20

What formula is used to calculate current in a circuit?

Answer 20

I = E / R

Question 21

What formula is used to calculate voltage in a circuit?

Answer 21

E= I x R

Question 22

What formula is used to calculate resistance in a circuit?

Answer 22

R = E / I

Question 23

Electrical power is measured in which of the following units?

Answer 23

Power is measured in Watts, or W

Question 24

Which term describes the rate at which electrical energy is used?

Answer 24

Power, represented by P

Question 25

What is the formula used to calculate electrical power in a DC circuit?

Answer 25

The product of voltage and current (P = E x I)

Question 26

What is the ability to store energy in an electric field called?

Answer 26

Capacitance, measured in faraday (F)

Question 27

What is the ability to store energy in a magnetic field called?

Answer 27

Inductance, measured in Henry’s (H)

Question 28

What electrical component opposes the flow of current in a DC circuit?

Answer 28

Resistors

Question 29

What type of component is often used as an adjustable volume control?

Answer 29

Potentiometer

Question 30

What electrical parameter is controlled by a potentiometer?

Answer 30

Adjusts voltage or potential

Question 31

What electrical component stores energy in an electric field?

Answer 31

Capacitors

Question 32

What type of electrical component consists of two or more conductive surfaces separated by an insulator?

Answer 32

Capacitors

Question 33

What type of electrical component stores energy in a magnetic field?

Answer 33

Inductors

Question 34

What electrical component usually is constructed as a coil of wire?

Answer 34

Inductors

Question 35

What component is commonly used to change 120V AC house current to a lower AC voltage for other uses?

Answer 35

Transformer

Question 36

What is impedance?

Answer 36

A general term to mean the circuit’s opposition to AC current flow, a combination of resistance and reactance, measured in Ohms

Question 37

Which of the following is combined with an inductor to make a tuned circuit?

Answer 37

A capacitor is combined with an inductor to make a tuned circuit

Question 38

What is the main purpose of a resonant or tuned circuit?

Answer 38

A tuned circuit acts as a filter, passing or rejecting signals at its resonant frequency.

Question 39

What class of electronic component uses a voltage or current signal to control current flow?

Answer 39

Transistors

Question 40

What electronic component allows current to flow in only one direction?

Answer 40

A Semiconductor

Question 41

Which component can be used as an electronic switch or amplifier?

Answer 41

With an appropriate external circuit and a source of power, transistors can amplify or switch voltages and currents

Question 42

Which component can consist of three layers of semiconductor material?

Answer 42

Transistors

Question 43

Which electronic component can amplify signals?

Answer 43

Transistors

Question 44

How is the cathode lead of a semiconductor diode often marked on a package?

Answer 44

By a stripe mark

Question 45

What does the abbreviation LED stand for?

Answer 45

Light Emitting Diode

Question 46

What does the abbreviation FET stand for?

Answer 46

Field-Effect Transistors

Question 47

What does BJT stand for?

Answer 47

Bipolar Junction Transistors

Question 48

What are the names of the two electrodes of a diode?

Answer 48

Anode and Cathode

Question 49

Which of the following could be the primary gain-producing component in an RF power amplified?

Answer 49

RF power transistors

Question 50

What is the term that describes a device’s ability to amplify a signal?

Answer 50

Using small signals to control or amplify larger signals is called gain

Question 51

Which of the following devices or circuits changes an alternating current into a varying direct current signal?

Answer 51

Diode

Question 52

Which of the following is commonly used as a visual indicator?

Answer 52

LEDs

Question 53

What is the name of a device that combines several semiconductors and other components into one package?

Answer 53

Integrated Circuit (IC or chip)

Question 54

What electrical component is used to protect other circuit components from current overloads?

Answer 54

Fuses and circuit breakers

Question 55

What is the purpose of a fuse in an electrical circuit?

Answer 55

What the metal melts, or “blows”, the current path is broken and power is removed from circuits supplied by the fuse.

Question 56

Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?

Answer 56

Using one with a higher current rating, even temporarily, could allow the fault to permanently damage the equipment or start a fire.

Question 57

What electrical component is used to connect or disconnect electrical circuits?

Answer 57

Switches and relays control current through a circuit

Question 58

What is a relay?

Answer 58

A relay is a switch controlled by an electromagnet

Question 59

What is the name of an electrical wiring diagram that uses standard component symbols?

Answer 59

Schematics

Question 60

What do the symbols on an electrical schematic represent?

Answer 60

Visual description of a circuit and its components that uses standardized drawings called circuit symbols.

Question 61

Which of the following is accurately represented in electrical schematics?

Answer 61

Each line indicates that an electrical connection exists between the component at the end of the line.

Question 62

What is the name of a circuit that generates a signal at a specific frequency?

Answer 62

An oscillator

Question 63

Which of the following describes combining speech with an RF carrier signal?

Answer 63

Modulation

Question 64

Which of the following is used to convert a radio signal from one frequency to another?

Answer 64

A mixer, combines two RF signals and shifts one of them to a third frequency

Question 65

Which of the following might damage a multimeter?

Answer 65

Trying to measure voltage or connecting the probes to an energized circuit when the meter is set to measure resistance

Question 66

Which of the following measurements are commonly made using a multimeter?

Answer 66

All three electrical values of voltage, current and resistance.

Question 67

What is probably happening when an oh meter, connected across an unpowered circuit, initially indicates a low resistance and then shows increasing resistance with time?

Answer 67

Indicates the presence of a large-value capacitor.

Question 68

Which of the following precautions should be taken when measuring high voltages with a voltmeter?

Answer 68

Ensure the voltmeter and leads are rated for use at the voltages to be measured.

Question 69

Which of the following displays an electrical quantity as a numeric value?

Answer 69

A meter provides information as a value in the form of numbers or on a numeric scale.