# Basic Electronics

## Full text

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### I - VOLTAGE AND CURRENT

1. What is the color code for a 220 5% resistor?

A. Red, Red, Brown, Gold

B. Orange, Orange, Black, Gold

C. Red, Red, Black, Gold

D. Red, Red, Brown, Silver

Explanation: Resistor colour coding series:

Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Gray 8 White 9 None 20% Silver 10% Gold 5%

Therefore Red, Red, Brown, Gold 2 2 101 5%

= 22 x 10 = 220 ohm 5% (tolerance).

2. If 60 J of energy areevery 15 C of charge, what is the voltage? A. 4 V B. 60 V C. 15 V D. 0.25 V Answer: Option A

3. An atom's atomic number is determined by the number of:

A. neutrons minus protons

B. protons

C. electrons

D. neutrons

4. A voltage will influence current only if the circuit is:

A. open

B. insulated

C. high resistance

D. closed

5. Which resistive component is designed to be temperature sensitive? A. Thermistor B. Rheostat C. Potentiometer D. Photoconductive cell Answer: Option A

6. The battery symbol is:

A.

B. C. D.

7. What type of switch is this?

A. push button

B. SPST

C. DPDT

D. SPDT

8. Primary batteries, unlike secondary batteries, may be:

A. charged once

B. used once

C. recharged over and over

D. stored indefinitely

Explanation: Primary batteries

(disposable batteries), which are designed to be used once and discarded when they are exhausted. Secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times.

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voltage:

A. is restored as soon as disconnect occurs

B. is lowered as the load increases

C. may be stored indefinitely

D. will be reduced to zero as power is drawn

10. The negative and positive charge symbols are assigned (in that order) to the:

A. proton and electron

B. electron and proton

C. atom and nucleus

D. electron and element

11. A voltmeter is used:

A. to measure current

B. in series with the circuit

C. in parallel with the circuit

D. to measure coulombs

12. If the current in a circuit equals 0 A, it is likely that the

A. voltage is too high

B. resistance is too low

C. circuit has a short

D. circuit is open Answer: Option D 13. Current equals: A. B. coulombs × time C. D. voltage × time Answer: Option A

14. What are the unit and symbol for current?

A. Ampere, A

B. Coulomb, I

C. Ampere, Q

D. Ampere, I

15. Which part of an atom has no electrical charge?

A. Electron

B. Neutron

C. Proton

D. All of the above

16. Which voltage source converts chemical energy to electrical energy?

A. Electrical generator

B. Battery

C. Solar cell

D. Electronic power supply

17. An example of potential energy is:

A. tea-kettle steam

B. a moving vehicle

C. the sun

D. a battery

18. If 40 C of charge flow past a point in 20 s, what is the current?

A. 2 A B. 0.5 A

C. 20 A D. 40 A

19. Batteries differ from fuel cells in that

A. a battery is a closed system

B. a battery uses hydrogen and oxygen to create electricity

C. a battery uses a polymer electrolyte membrane

D. none of the above

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20. The removal of a non-neutral subatomic particle converts the atom into a:

A. charged ion

B. nucleus

C. heavier element

D. compound

21. One coulomb passing a point in one second is one:

A. ampere B. volt

C. ohm D. charge

22. In which states may matter may be found?

A. solid, liquid, or mineral

B. solid, gas, or liquid

C. mineral, gas, or liquid

D. plastic, solid, or gas

23. Material that consists of a mixture of elements is considered to be:

A. an element B. an ion

C. a compound D. a molecule

24. How many valence shell electrons are there in semiconductor atoms?

A. 16 B. 8

C. 4 D. 2

25. When considering conventional current versus electron current flow:

A. electron current flow came first

B. protons move in conventional current flow

C. conventional current flow came first

D. the direction of current is the same in both methods

26. Which unit of charge contains 6.25 × 1018 electrons?

A. An ampere B. A coulomb

C. A volt D. A joule

27. A switch is a device that:

A. short circuits complex circuits

B. holds a fuse

C. has double poles

D. opens or completes a current path

28. The term used to designate electrical pressure is:

A. voltage B. current

C. resistance D. conductance

29. Which electronics material opposes the movement of free electrons?

A. Conductor B. Insulator

C. Semiconductor D. Element

30. Current is considered as the movement of:

A. electrons B. protons

C. charge D. nuclei

31. A lead-acid battery is an example of a

A. solar cell

B. fuel cell

C. primary battery

D. secondary battery

32. The charge of one coulomb is equal to:

A. 6.24 x 10−18 electrons

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C. one second

D. 6.24 x 1018 electrons

33. A basic electric circuit is made up of what components?

A. A load, a resistor, and a conductive path for current

B. A voltage source, a load, and a conductive path for current

C. A voltage source, a conductive path for current, and a battery

D.

A conductive path for current, a battery, and a copper wire

34. An ammeter is used to measure

A. voltage B. current

C. resistance D. All of the above

35. What is the name of the pressure that moves electrons in a closed circuit?

A. amperes B. ohms

C. voltage D. coulombs

36. What is a characteristic of a secondary cell?

A. rechargeability

B. not rechargeable

C. a dry cell

D. non-liquid

37. What are the basic building blocks that all matter is composed of?

A. electrons, neutrons, and protons

B. two protons for each neutron

C. two protons for each electron

D. electrons, neutrons, and charged ions

38. If a fluid system is compared to an electrical system, the fluid pump will correspond to a:

A. conductor B. lamp

C. battery D. insulator

39. An element is a substance that is:

A. varied throughout the entire piece

B. used only in electronics

C. electrically charged

D. found only in its pure form

40. Current is:

A. the presence of a positive charge

B. the abundance of electrons

C. the movement of electrons

D. the repulsion of electrons

41. What do you call a diagram that shows the electrical connections of a circuit's components?

A. A schematic diagram

B. A pictorial diagram

C. A block diagram

D. An electrical diagram

42. A short circuit will have:

A. a small current flow

B. a large current flow

C. no current flow

D. some current flow

43. The basic difference between a fuse and a circuit breaker is

A. a fuse is slower

B. a fuse is reusable

C. a circuit breaker is reusable

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44. Which is the smallest?

A. atom B. proton

C. neutron D. electron

45. A secondary cell generates dc via chemical activity; a primary cell generates dc:

A. electrically B. thermally

C. optically D. chemically

46. Which of the following statements is true?

A. Unlike charges repel and like charges attract.

B. Like charges repel and unlike charges attract.

C. Unlike charges attract and like charges attract.

D. Like charges repel and unlike charges repel.

47. If an electrical system is compared to a fluid system, the electrical current corresponds to the:

A. pressure B. pump

C. water wheel D. water flow

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II - Series Circuits

1. What is the current flow through R1, R2, and R3?

A. 1A, 1A, 1A B. 1A, 2A, 3A C. 3A, 3A, 3A D. 3A, 2A, 1A Answer: Option A Explanation: V = IR V = I(R1 + R2 + R3) I = V/(R1 + R2 + R3) = 9/(3 + 3 + 3) = 9/9 = 1 Amp.

2. One of the most common applications of a potentiometer is as an adjustable voltage divider, also known as A. voltage control B. current control C. volume control D. divider control Answer: Option C

3. If the resistance total in a series circuit doubles, current will:

A. be the same

B. be doubled

C. reduce source voltage

D. be halved

4. Power is defined as:

A. the rate at which work is done

B. work

C. the conversion of energy

D. joules

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A. 78 V

B. 39 V

C. 13 V

D. 0 V

6. With a total resistance of 3300 ohms and a 45 V source, if R3 is 1200 ohms, what will be its voltage drop? A. 16.36 V B. 32.72 V C. 10.90 V D. 15.00 V Answer: Option A 7.

Calculate the voltage at point B in the given circuit.

A. +10.48 V B. +0.94 V C. +2.6 V D. +3 V Answer: Option A 8.

In the given circuit, what type of failure will cause the voltage at point B to equal the voltage at point C? A. R1 shorts B. R2 shorts C. R3 shorts D. R2 opens Answer: Option B 9.

What is the voltage at points B to D in the given circuit?

A. +19.2 V B. +8.8 V C. +28 V D. –19.2 V Answer: Option A 10.

Calculate the voltage at point C in the given circuit.

A. +1.48 V

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C. +11.6 V

D. +3 V

11. An 8-ohm resistor is in series with a lamp. The circuit current is 1 A. With 20 V applied, what voltage is being allowed for the lamp?

A. 4 V

B. 8 V

C. 12 V

D. 20 V

12. What is wrong, if anything, with this circuit?

A. R1 is open.

B. R1 is shorted.

C. R2 is open.

D. R2 is shorted.

13. Kirchhoff’s voltage law states that:

A. the sum of the voltage drops in a series circuit is equal to the total applied voltage

B. the algebraic sum of the resistances is equal to the sum of the voltages

C. the algebraic sum of the individual currents around a closed loop is zero

D. the voltages developed across each element in a series circuit are identical

14. If series current doubles, then:

A. resistance is halved

B. voltage is doubled

C. voltage is reduced

D. resistance is doubled

15. What are the minimum and maximum output voltages?

A. 0 V, 4 V

B. 0 V, 8 V

C. 0 V, 12 V

D. 0 V, 16 V

16. A short circuit has:

A. too much resistance

B. no conductance

C. no resistance

D. low current

17. If three resistors of 1.5 kilohms, 470 ohms, and 3300 ohms are in series with a 25-volt source, what is the total circuit current?

A. 210 mA

B. 5.2 mA

C. 4.7 mA

D. .007 A

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A. 170 mW

B. 1.7 W

C. 17 W

D. 170 W

19. A string of resistors in a series circuit will:

A. divide the source voltage in proportion to their values

B. reduce the power to zero

C. cause the current to divide

D. increase the source voltage in proportion to the values

20.

While putting three 1.5 V batteries into a flashlight, you put one in backwards. The flashlight will be ______________.

A. brighter than normal

B. dimmer than normal

C. off

D. the same

21.

If a voltage is connected between contacts 2 and 3 in

the given circuit, which resistors will carry current?

A. All twelve resistors will carry current.

B. Only R6 and R11 will carry current.

C. Only R2, R4, R6, and R11 will carry current.

D. Only R3, R6, R9, and R12 will carry current.

22. Given a series circuit containing resistors of different values, which statement is not true?

A. The current through each resistor is the same.

B. The sum of the voltage drops across each resistive element will be equal.

C. The total resistance is the sum of the value of the resistors.

D. The voltage drop across each resistor is the same.

23. With 20 V applied, an 8-ohm resistor is in series with a lamp. When the lamp is removed, what voltage will be read across the lamp socket?

A. 0 V

B. 8 V

C. 12 V

D. 20 V

24. When 50 V is applied to four series resistors, 100 µA flows. If R1 = 12 k , R2 = 47 k , and R3 = 57 k , what is the value of R4?

A. 38.4 k B. 3.84 k C. 384 k D. 3.84 M Answer: Option C 25.

In a series circuit, the voltage measured across a short will be:

A. source voltage

B. infinite voltage

C. zero volts

D. the normal voltage drop

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26.

Which is a true statement about the circuit in the given circuit?

A. The batteries are series-aiding and the total source voltage equals 21 V.

B. The batteries are series-opposing and the total source voltage equals 3 V.

C. The batteries are series-aiding and the total source voltage equals 3 V.

D. The batteries are series-opposing and the total source voltage equals 21 V.

27. A series circuit current:

A. remains the same through each component

B. is the same as the individual resistances

C. is subtracted by each component

D. varies through each component

28.

If R2 opens in the given circuit, what is the voltage at point B? A. +19.2 V B. +8.8 V C. +28 V D. –19.2 V Answer: Option C

29. If 5 V and 16 V power supplies are connected in

series-opposing, what is the total voltage?

A. 11 V

B. 16 V

C. 21 V

D. 80 V

30. What is the total resistance?

A. 0 k ; there is no current

B. 2 k ; the average

C. 3 k ; the largest

D. 6 k ; the sum

31. Which equation determines individual resistor voltage drop? A. V x R B. I2 x R C. V x I D. I x R Answer: Option D

32. How will an open resistor affect a series circuit?

A. Current will flow around the open resistor.

B. The open resistor will drop 0 V.

C. Total resistance will decrease.

D. No current will flow in the circuit.

33. The voltage drop across a series resistor is proportional to what other value?

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A. total resistance

B. its own resistance

C. wattage rating

D. the amount of time the circuit is on

34. Resistance in a series circuit will:

A. control the voltage

B. double the current

C. halve the power

D. oppose current

35.

When a battery is connected to a series circuit, it delivers current based only upon:

A. primary/secondary difference

B. total resistance

C. the polarity connections

D. average resistance

36. What determines the total resistance in a series circuit?

A. the largest resistor

B. the sum of the resistors

C. the largest resistor minus the smaller

D. the smallest resistor

37. If two resistors have the same voltage drop in a series circuit, it means:

A. they are connected in parallel

B. they are of unequal value

C. the voltage has doubled

D. they are of equal value

38. If series resistors dissipate 16 mW, 107 mW, 146 mW, and 243 mW, what is the total power consumed by the circuit?

A. 128 mW

B. 269 mW

C. 512 mW

D. 1024 mW

39. A series circuit schematic is recognized because all the components are connected:

A. diagonally across the page

B. in a uniform vertical manner

C. end to end in a "string"

D. horizontally across the page

40. With a 900 V source, voltage is divided across 3 series resistors of 300 V, 280 V, and:

A. 30 V B. 270 V C. 320 V D. 900 V Answer: Option C 41.

How much current flows in the circuit in the given circuit? A. 20 A B. 60 A C. 80 A D. 140 A Answer: Option A ________________________________________ _______________________________________

### III - PARALLEL CIRCUITS

1. When parallel resistors are of three different values, which has the greatest power loss?

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A. The smallest resistance

B. The largest resistance

C. They have the same power loss.

D. Voltage and resistance values are needed.

2. What is the product-over-sum result of 150 and 6800?

A. 150 B. 146.7

C. 0.006 D. 6800

3. The voltage across any branch of a parallel circuit:

A. varies as the total current varies

B. is inversely proportional to total circuit resistance

C. is equally applied to all branch conductances

D. is dropped in proportion to each branch resistance

4. What is the total power loss if 2 k and 1 k parallel-connected resistors have an ITof 3 mA?

A. 6 W B. 36 W

C. 6 mW D. 36 mW

5. What happens to total resistance in a circuit with parallel resistors if one of them opens?

A. It increases. B. It halves.

C. It remains the same. D. It decreases.

6. Components that connect in parallel form:

A. branches B. open circuits

C. short circuits D. a voltage divider

7. A parallel circuit differs from a series circuit in that a parallel circuit has

A. no path for current flow

B. fewer paths for current flow

C. one path for current flow

D. more than one path for current flow

8.

In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to the speakers. How much total current is the amplifier providing to the speakers?

A. 0 A

B. 1.5 A

C. 3 A

D. More information is needed to find the total current provided to the speakers.

9. If two parallel-connected resistors dissipate 6 watts and 10 watts of power, then what is the total power loss? A. 3.75 watts B. 4 watts C. 16 watts D. 60 watts Answer: Option C 1 0.

Which component is shorted?

A. R1 B. R2

C. R3 D. R4

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11.

What would these meter readings indicate about the circuit in the given circuit?

Meter Readings: I = 7.6 mA, V = 12 V

A. R1 is open.

B. R2 is open.

C. The fuse is open.

D. The circuit is operating normally.

12.

In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to the speakers. How much total power is the amplifier delivering to the speakers?

A. 0 W

B. 18 W

C. 36 W

D. More information is needed to find the total power delivered to the speakers.

13. If a 1 k and a 2 k resistor are parallel-connected across a 12 V supply, how much current is received by the 2 k resistor? A. 4 mA B. 6 mA C. 8 mA D. 12 mA Answer: Option B 1 4.

What does VS equal in the given circuit?

A. 0 V

B. 9 V

C. 27 V

15. The current through R1 will be:

A. 128 mA B. 88 mA

C. 48 mA D. 2.2 mA

16. The voltage read by the voltmeter will be:

A. 24 V B. 12 V

C. 6 V D. 4 V

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A. R1 B. R2

C. R3 D. R4

18.

What does I3 equal in the given circuit?

A. 5 mA B. 45 mA

C. 50 mA D. 100 mA

19. What is the total power of the circuit?

A. 2.2 W B. 4.2 W

C. 6.2 W D. 8.2 W

20. What are the individual values of two parallel resistors whose RT is 8 ohms, when one has double the resistance of the other?

A. 2.7 ohms and 5.3 ohms

B. 8 ohms and 16 ohms

C. 10 ohms and 20 ohms

D. 12 ohms and 24 ohms

21. When a parallel 5 k resistor and a 25 k resistor have a 10 V supply, what is the total power loss?

A. 2.4 mW B. 3.3 mW

C. 24 mW D. 33 mW

22. In a parallel resistive circuit:

A. there is more than one current path between two points

B. the voltage applied divides between the branches

C. the total branch power exceeds the source power

D. the total circuit conductance is less than the smallest branch conductance

23 .

What is the total resistance?

A. 7 k B. 1 k

C. 706 D. 353

24. Kirchhoff's current law for parallel circuits states that the:

A. sum of all branch voltages equals zero

B. total circuit resistance is less than the smallest branch resistor

C. sum of currents into a junction is equal to the difference of all the branch currents

D. sum of the total currents flowing out of a junction equals the sum of the total currents flowing into that junction

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5. A. R1 B. R2 C. R3 D. R4 Answer: Option C 2 6.

What would these meter readings indicate about the circuit in the given circuit?

Meter Readings: I = 0 mA, V = 0 V

A. R1 is open.

B. R2 is open.

C. The fuse is open.

D. The circuit is operating normally.

27. If 550 mA of current leaves a node that had 250 mA entering from one branch, how much current would enter from the other?

A. 250 mA B. 300 mA C. 550 mA D. 800 mA Answer: Option B 2 8.

What would these meter readings indicate about the circuit in the given circuit?

Meter Readings: I = 10 mA, V = 12 V

A. R1 is open.

B. R2 is open.

C. The fuse is open.

D. The circuit is operating normally.

2 9.

What does RT equal in the given circuit?

A. 90 B. 180

C. 200 D. 1.8 k

30. What procedure should be followed when troubleshooting with an ammeter or voltmeter?

B. Check the meter’s external power supply.

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A. conductance B. voltage

C. power D. current

32. What is RT for a 12 k , a 4 k , and a 3 k resistor in parallel?

A. 1.5 k B. 2 k

C. 6.3 k D. 19 k

33. What is the total resistance of four 1 k parallel-connected resistors?

A. 200 ohms B. 250 ohms

C. 400 ohms D. 4 kilohms

34. Which are the better test devices used to isolate a suspected open component within a parallel circuit?

A. a voltmeter or an ohmmeter

B. neither an ammeter nor a voltmeter

C. a wattmeter or a voltmeter D. an ammeter or an ohmmeter Answer: Option D 3 5.

What does P2 equal in the given circuit?

A. 45 mW B. 405 mW C. 450 mW D. 900 mW Answer: Option B 3 6.

What does R1 equal in the given circuit?

A. 90 B. 180 C. 200 D. 1.8 k Answer: Option B 37 .

What is the total resistance?

A. 1.045 k B. 1.545 k

C. 2.045 k D. 2.545 k

38. What is RT for fifteen 2 M resistors all connected in parallel?

A. 133 k B. 300 k

C. 750 k D. 30 M

39. Which is considered to be the common reference for a parallel circuit?

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C. Power D. Resistance

IV - Series-Parallel Circuits

1. What theorem replaces a complex network with an equivalent circuit containing a source voltage and a series resistance? A. Multinetwork B. Norton C. Thevenin D. Superposition Answer: Option C 2.

What is the power dissipated by R2, R4, and R6?

A. P2 = 417 mW, P4 = 193 mW, P6 = 166 mW B. P2 = 407 mW, P4 = 183 mW, P6 = 156 mW C. P2 = 397 mW, P4 = 173 mW, P6 = 146 mW D. P2 = 387 mW, P4 = 163 mW, P6 = 136 mW Answer: Option A 3.

If the load in the given circit is 120 k , what is the loaded output voltage?

A. 4.21 V

B. 15.79 V

C. 16 V

D. 19.67 V

4. In a series–parallel circuit, individual component power dissipations are calculated using:

A. individual component parameters

B. a percent of the voltage division ratio squared

C. total current squared multiplied by the resistor values

D. a percent of the total power depending on resistor ratios

5. The current flowing through an unloaded voltage divider is called the: A. resistor current B. load current C. bleeder current D. voltage current Answer: Option C

6. When a Wheatstone bridge is in a balanced condition, the center voltmeter in the bridge will read:

A. twice the source voltage

B. the same as the source voltage

C. zero volts

D. half the source voltage

7. When a load is connected to a voltage divider, the total resistance of the circuit will:

A. Decrease

B. Double

C. Increase

D. remain the same

8. With 21 V applied, if R1 = 5 ohms, R2 = 35 ohms, and R3 = 14 ohms, what is the current of R2 if R1 is series connected with parallel circuit R2 and R3?

A. 200 mA

B. 800 mA

C. 600 mA

D. 400 mA

9. What is the total resistance of a circuit when R1 (7 k ) is in series with a parallel combination of R2 (20 k ), R3 (36 k ), and R4 (45 k )?

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A. 4 k B. 17 k C. 41 k D. 108 k Answer: Option B 10.

If the load in the given circuit is 80 k , what is the bleeder current?

A. 196 A B. 1.96 mA C. 2 mA D. 2.16 mA Answer: Option B 11 .

What is the total resistance of the given circuit? A. 92 B. 288 C. 17.7 D. 128 Answer: Option A

12 What are the branch currents I2 and I3?

. A. I2 = 4 mA, I3 = 2 mA B. I2 = 4.5 mA, I3 = 2.5 mA C. I2 = 5 mA, I3 = 3 mA D. I2 = 5.5 mA, I3 = 3.5 mA Answer: Option C 13 .

If the load in the given circuit is open, what is the unloaded output voltage?

A. 0 V B. 4 V C. 16 V D. 20 V Answer: Option C 1 4 .

What is the total resistance?

A. 2.2 k

B. 3.2 k

C. 4.2 k

D. 5.2 k

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15 .

How much voltage is dropped across R3 in the given circuit?

A. 46 V B. 34 V C. 23 V D. 12 V Answer: Option D 1 6 .

When placed into a circuit, how are electronic components usually connected?

A. positive terminal to positive terminal

B. in parallel

C. as a combination of series and parallel

D. in series

17.

If the load in the given circuit is 12 k , what is the loaded output voltage?

A. 5.88 V

B. 14.12 V

C. 16 V

D. 17.14 V

18. If a Wheatstone bridge is balanced, a voltmeter in the center of the bridge will read:

A. the same as the source voltage

B. half the source voltage

C. zero volts

D. twice the source voltage

19. What is the voltage to the load?

A. 11.4 V B. 12.4 V C. 13.4 V D. 15.4 V Answer: Option D 20.

The first goal to accomplish in analyzing a complex series-parallel circuit is to

A. equate all parallel components

B. equate all series components

C. solve for all the voltage drops

D. solve for the total current and resistance

21 .

Which circuit fault do the meter readings in the given figure indicate?

A. The 1 k resistor is open.

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C. The 2.2 k resistor is open.

D. The 3.3 k resistor is open.

22.

How much current is flowing through R1 in the given circuit? A. 0.3 A B. 0.15 A C. 0.5 A D. 0.68 A Answer: Option C

23. If R1 is in series with parallel connected to R2 and R3, what happens to total current if R2 opens?

A. Increases

B. Decreases

C. remains the same

D. cannot tell

24. The first goal(s) to accomplish in analyzing a complex series–parallel circuit is to:

A. equate all parallel components

B. equate all series components

C. solve for all the voltage drops

D. solve for the total current and resistance

25. If a series–parallel circuit has all 30-ohm resistors, what is the total resistance when R1 is in series with a parallel circuit consisting of R2 and R3?

A. 10 ohms B. 20 ohms C. 45 ohms D. 90 ohms Answer: Option C 26.

Components or combinations of components with common currents, in a series–parallel circuit, are in:

A. parallel with each other

B. series with each other

C. either series or parallel with each other

D. none of the above

27. What determines if resistor connections are in series, parallel, or series–parallel?

A. the voltage source

B. the power source

C. Resistance

D. current flow

28 .

What is the total resistance?

A. 800

B. 1.2 k

C. 1.6 k

D. 1.8 k

29. If R1 is in series with a parallel combination of R2, R3, and R4, when the resistance value of R2 increases, the voltage across R3 will

A. Increase

B. Decrease

C. remain the same

D. Cannot tell

30A Wheatstone bridge can be used to determine an unknown

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. A. Current B. resistance

C. Power D. voltage

31 .

Which circuit fault do the meter readings in the given figure indicate?

A. The 1 k resistor is shorted.

B. The 4.7 k resistor is shorted.

C. The 2.2 k resistor is shorted.

D. The 3.3 k resistor is shorted.

32. In a series–parallel circuit consisting of R1 and R2 in series and connected in parallel with R3, if R1 opens, then R2's voltage will:

A. Increase

B. Decrease

C. remain the same

D. cannot tell

33.

In the given circuit, what is RUNK equal to if RV must be adjusted to 1,232 in order to balance the bridge?

A. 220

B. 6,899

C. 1,232

UNK.

34. With 6 V applied, what is the voltage across R2 of a parallel combination of R2 (1 k ), R3 (2 k ), and R4 (1 k ) in series with R1, whose value is 2 k ?

A. 1 V

B. 3 V

C. 5 V

D. 6 V

35. What is the power dissipated by R1, R2, and R3?

A. P1 = 0.13 W, P2 = 0.26 W, P3 = 0.12 W B. P1 = 0.26 W, P2 = 0.52 W, P3 = 0.23 W C. P1 = 0.52 W, P2 = 0.92 W, P3 = 0.46 W D. P1 = 1.04 W, P2 = 1.84 W, P3 = 0.92 W Answer: Option B

### V - CAPACITORS

1. In a 20 Vac series RC circuit, if 20 V is measured across the resistor and 40 V is measured across the capacitor, the applied voltage is:

A. 45 V

B. 50 V

C. 55 V

D. 60 V

2. Select the equation below that represents the

relationship between charge, capacitance, and voltage for a capacitor.

(21)

B. C = QV

C.

D. V = IR

3. When is a capacitor fully charged?

A. when the voltage across its plates is of the

voltage from ground to one of its plates

B. when the current through the capacitor is the same as when the capacitor is discharged

C. when the voltage across the plates is 0.707 of the input voltage

D. when the current through the capacitor is directly proportional to the area of the plates

4.

What is the reactive power in the given circuit?

A. 0 VAR

B. 691 VAR

C. 44.23 mVAR

D. 1.45 kVAR

5. What is the angle theta value for a 5.6 F capacitor and a 50-ohm resistor in series with a 1.1 kHz, 5 Vac source?

A. 27.3 degrees

B. 62.7 degrees

C. –27.3 degrees

D. –62.7 degrees

6. When a 4.7 F capacitor is connected to a 1 kHz source, what is its capacitive reactance?

A. 4.7 ohms

B. 29.5 ohms

C. 34 ohms

D. 213 ohms

7. What is the total capacitance?

A. 1 F

B. 12 F

C. 0.615 F

D. 8 F

8. What is this circuit?

A. bandpass filter

B. high-pass filter

C. low-pass filter

D. differentiator

9. After which time constant can a capacitor be considered to be fully charged?

A. first B. third

C. fifth D. seventh

10. You could increase the time constant of an RC circuit by

(22)

B. adding a capacitor in parallel with the circuit capacitance

C. increasing the amplitude of the input voltage

D. exchanging the position of the resistor and capacitor in the circuit

11. A capacitor's rate of charge is considered:

A. magnetic

B. a current block

C. linear

D. exponential

12. A resistor and an output capacitor form a series circuit with a square wave applied. The circuit is:

A. an integrator

B. a differentiator

C. a multiplier

D. a divider

13. If an open capacitor is checked with an ohmmeter, the needle will:

A. stay on zero

B. stay on infinity

C. move from zero to infinity

D. move from infinity to zero

14. What is the circuit's total current?

A. 4.57 mA

B. 9.327 mA

C. 11.570 mA

D. 13.830 mA

15. As a capacitor is being charged, current flowing into the capacitor will:

A. increase

B. decrease

C. remain the same

D. cannot tell

16. What is the phase shift between the voltage across the resistor and the voltage from the source?

A. VR leads VS by 17°

B. VR leads VS by 73°

C. VR lags VS by 73°

D. VR lags VS by 17°

17. A capacitor stores energy within a dielectric between the conducting plates in the form of:

A. a magnetic field

B. positive voltage

C. negative voltage

D. an electric field

18. As a capacitor is being charged, the voltage across its terminals will:

(23)

B. decrease

C. remain the same

D. oppose the source

19. With a 500 kHz signal source, what would be the value of a capacitor yielding a capacitive reactance of 1 k ?

A. 318 pF

B. 2 nF

C. 3.18 F

D. 2 F

20. After a capacitor has charged for 1 tc, what percentage of current remains in the resistor?

A. 63.2 B. 36.8

C. 13.5 D. 5.0

21. If a current of 40 mA flows through a series circuit consisting of a 0.4 F capacitor and a resistor in series with a 4 kHz, 40 Vac source, what is the total circuit impedance? A. 10 B. 100 C. 1 k D. 1 M Answer: Option C 22.

What is the capacitance of the circuit shown in the given circuit? A. 0.066 F B. 0.9 F C. 65.97 pF D. 900 pF Answer: Option A

23. In an ac circuit, an output capacitor and a resistor are connected in series with an ac signal. What filter action will be the result?

A. bandpass B. low-pass

C. high-pass D. band-stop

24. What is the total opposition to current in a series RC circuit called?

A. impedance B. inductance

C. reactance D. resistance

25. Which of the following statements is true?

A. The voltage to which a capacitor is charged can change instantaneously.

B. The current in a capacitive circuit takes time to change.

C. A fully charged capacitor appears as a short to dc current.

D. An uncharged capacitor appears as a short to an instantaneous change in current.

26. In a capacitive circuit, current flow is limited to

A. charging periods

B. discharging periods

C. neither charging periods nor discharging periods

D. both charging periods and discharging periods

27 .

What circuit has the following frequency response?

A. bandpass filter

B. high-pass filter

(24)

D. integrator

28. A capacitor is constructed of two parallel:

A. conductors B. semiconductors

C. inductors D. dielectrics

29. Which of the following determines the capacitance of a capacitor?

A. Plate area, dielectric strength, and plate separation

B. Voltage rating, dielectric constant, and temperature coefficient

C. Temperature coefficient, plate area, and plate separation

D. Plate area, dielectric constant, and plate separation

30. Most older types of paper capacitors have been replaced by which type of construction?

A. electrolytic B. plastic film C. oxide casing D. waxed paper Answer: Option B 31. If C1, a 4.7 F capacitor, and C2, a 3.3 F capacitor are in series with 18 Vdc applied, what is the voltage across C1?

A. 3.3 V

B. 7.4 V

C. 6.6 V

D. 9.4 V

32. What is the impedance of a series RC circuit that consists of a 0.22 F capacitor and a 200-ohm resistor connected to a 3 kHz source? A. 214 ohms B. 313 ohms C. 414 ohms D. 880 ohms Answer: Option B

33. What is the reactance value for a capacitor installed in a dc circuit? A. zero B. moderate C. infinite D. cannot tell Answer: Option C

34. In a purely capacitive circuit,

A. current leads voltage by 90°

B. voltage leads current by 90°

C. current lags voltage by 90°

D. current and voltage have a phase relationship of 0°

3 5.

How long would it take the capacitor in the given circuit to completely discharge if the switch was in position 2?

A. 22 ms

B. 69 ms

C. 345 ms

D. 420 ms

36. What is the capacitive reactance if I = 1 amp, V = 2 volts, C = 5 F, and frequency = 10 Hz?

A. 0.2

B. 0.5

C. 0.02

D. 0.003

(25)

37. What is wrong with a leaky capacitor?

A. It is open.

B. It is shorted.

C. The dielectric resistance has increased.

D. The dielectric resistance has decreased.

38. What is the value of a capacitor labeled 102?

A. 10,000 pF

B. 1000 pF

C. 1000 F

D. 10,000 F

39. If the dielectric constant of a capacitor is decreased, then its capacitance will:

A. increase

B. decrease

C. remain the same

D. be destroyed

40. What is the dielectric constant for ceramic?

A. between 6 and 8000

B. 5.0

C. between 5 and 1000

D. 3000

41. What is the voltage across a capacitor after being charged from a 100 V source for a period of one time constant? A. 37.8 V B. 38 V C. 63 V D. 101 V Answer: Option C

42. What is the dc charging/discharging time constant for the circuit? A. 294 ps B. 13.5 ms C. 21.25 ms D. 2.16 Gs Answer: Option C

43. Power stored from the source and then returned to the source is called: A. apparent power B. impedance power C. reactive power D. true power Answer: Option C

44. Capacitor value markings are usually:

A. alphanumeric B. color dabs C. standard D. white print Answer: Option A 45 .

A source voltage across a capacitor will:

A. lead the current by 90 degrees

B. lead the current by 180 degrees

C. lag the current by 90 degrees

D. lag the current by 180 degrees

(26)

46 .

How long would it take the capacitor in the given circuit to completely charge if the switch was in position 1?

A. 22 ms

B. 69 ms

C. 345 ms

D. 440 ms

47. An 8 V power source is charging a capacitor. How many volts will be across the capacitor at the second time constant? A. 1 volt B. 3 volts C. 5 volts D. 7 volts Answer: Option D

48. The material used between the plates of a capacitor is called its: A. insulation material B. dielectric material C. separation material D. plate-divider material Answer: Option B

49. When a circuit consists of a capacitor and a resistor in series with a voltage source, and the voltage across the resistor is zero, then the capacitor is:

A. charging

B. discharging

C. fully charged

D. fully discharged

50. Which material has the highest dielectric strength?

A. Air B. Paper

C. Mica D. Oil

51. What is the circuit's impedance?

A. 1192

B. 843

C. 723

D. 511

52. In an ac circuit, a capacitor and an output resistor are connected in series with an ac signal. What filter action will be the result?

A. bandpass B. low-pass

C. high-pass D. band-stop

53. What is the impedance of this circuit?

A. 2098

B. 2000

(27)

D. 1798

54. What is the reactive power?

A. 6.8 mW B. 9.8 mW C. 12.8 mW D. 15.8 mW Answer: Option B 55. A practical capacitor A. is a short to dc

B. looks like a capacitor in parallel with a resistor

C. is an open to ac

D. stores energy in a magnetic field

56. Which of the following is the reference vector for parallel RC circuits?

A. R B. I

C. C D. V

57. What do variable capacitors use for dielectric?

A. ceramic, electrolytic, mica, or paper

B. air, ceramic, mica, or plastic

C. ceramic, paper, plastic, or mica

D. mica, ceramic, plastic, or electrolytic

58. If a charged capacitor is disconnected from a circuit, it

will:

A. immediately discharge

B. recharge

C. remain charged

D. leak the charge

59. What is the total current for a 5 MHz, 1 Vac circuit that consists of a 27 pF capacitor and a 1 k resistor connected in parallel? A. 459 A B. 647 A C. 1.31 mA D. 1.85 mA Answer: Option C

60. What is the value of a capacitor that can store two coulombs of charge when 500 volts is applied across its plates? A. 4 F B. 250 F C. 4,000 F D. 250 F Answer: Option C

61. The strength of an electric field at a given point is proportional to the potential difference on the plates and inversely proportional to the:

A. plate separation

B. negative plate only

C. field strength

D. charge difference

62. How is ac current related to ac voltage in a purely capacitive circuit?

A. AC current is 0.707 of the ac voltage.

B. AC current lags ac voltage.

C. AC current is 0.637 of the ac voltage.

D. AC current leads ac voltage.

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A. 7.07 V

B. 1.11 V

C. 111 mV

D. 7.07 mV

64. For a given charge difference, electrostatic field strength varies according to:

A. plate differential

B. plate area

C. plate distance

D. dielectric quantity

65. A capacitor has 25 V across its plates and a stored charge of 1500 C. What is the capacitance value? A. 60 pF B. 60 F C. 16.67 mF D. 37.5 mF Answer: Option B

66. A capacitor and an output resistor form a series circuit with a square wave applied. The circuit is:

A. an integrator

B. a differentiator

C. a multiplier

D. a divider

67. Capacitive reactance values connected in series offer

A. an increase in total XC

B. a decrease in total XC

C. no change in total XC

D. total opposition to voltage in the circuit

68. The quantity that represents an ideal capacitor dissipating 0 W of power is A. instantaneous power B. true power C. reactive power D. resistive power Answer: Option B

69. If a capacitor is placed across a 20 V source, what will be the amount of charge after 5 tc?

A. 5.0 V

B. 12.8 V

C. 13.5 V

D. 20 V

70. What is the impedance of an ac RC parallel circuit if the resistance is 12 ohms and the capacitive reactance equals 5 ohms? A. 0.2 ohms B. 3.5 ohms C. 4.6 ohms D. 13 ohms Answer: Option C

71. What will a 1 F capacitor store?

A. one coulomb of charge

B. 6.24 x 1012 electrons

C. one volt

D. one A of current

72. In an RC circuit, true power (PR) equals:

(29)

B. VS × I

C. I2R

D. VT × RT

73. What is the power factor if the apparent power of a circuit is 5 W, while the true power is 4 W?

A. 0.0 W

B. 0.8 W

C. 1.0 W

D. 1.25 W

74. If the reactive power of a circuit is 50 mW while the apparent power is 64 mW, then what is the true power of the circuit? A. 14 mW B. 36 mW C. 40 mW D. 114 mW Answer: Option C

### VI – INDUCTORS

1. Electricity may be generated by a wire:

A. carrying current

B. wrapped as a coil

C. that has neutral domains

D. passing through a flux field

2.

In the given circuit, what will the voltage be

across R3 25 s after the switch is moved to position 2?

A. 2.88 V

B. 5.9 V

C. 8.34 V

D. 14 V

3. The electrical energy consumed by a coil is stored in the form of: A. an electrical field B. a force field C. an electrostatic field D. a magnetic field Answer: Option D

4. What is magnetic flux?

A. the number of lines of force in webers

B. the number of lines of force in maxwells

C. the number of lines of force in teslas

D. the number of lines of force in flux density

5. As current travels within a conductor:

A. the magnetic field aids the current

B. a magnetic field is developed around it

C. the wire tries to point north

D. an electrostatic field opposes the current

6. What type of device consists of a coil with a moveable iron core? A. solenoid B. reed switch C. relay D. armature Answer: Option A 7. What is hysteresis?

A. lead between cause and effect

B. lag between cause and effect

(30)

D. lag between voltage and current

8. In a purely inductive circuit,

A. current leads voltage by 90°

B. voltage lags current by 90°

C. voltage leads current by 90°

D. voltage and current are in phase (0°)

9. A series RL filter circuit with an output across the inductor will result in what type of filtering?

A. passing of the higher frequencies

B. passing of the lower frequencies

C. blocking of the higher frequencies

D. blocking of a certain range of frequencies

10.

What is the total inductance in the given circuit?

A. 160 mH

B. 300 mH

C. 900 mH

D. 1700 mH

11. On a schematic, dashed lines between two vertical coils usually mean the transformer has:

A. an air core

B. an iron core

C. a nonmetallic core

D. a ferrite core

12. Faraday's law states that the:

A. direction of the induced voltage produces an opposition

B. direction of an induced current produces an aiding effect

C. emf depends on the rate of cutting flux

D. emf is related to the direction of the current

13. A henry value divided by a circuit resistive value provides the:

A. counter emf value

B. induced voltage amplitude

C. rise or decay time constant

D. quality factor of the coil

14. What does Faraday's law concern?

A. a magnetic field in a coil

B. a magnetic field cutting a conductor

C. a magnetic field hystersis

D. a magnetic field in a conductor

15. The polarity of induced voltage while a field is collapsing is:

A. independent of the force creating it

B. opposite to the force creating it

C. identical to the force creating the field

D. present only if the force is stationary

16. What is the permeability of transformer iron?

A. 50 B. 450

C. 1,500 D. 5,500

17. Electromagnetism is the:

A. magnetic field caused by a permanent magnet

B. action between a permanent and an artificial magnet

C. magnetic field action with a current-carrying wire

(31)

18. A magnetic field has:

A. polar fields

B. lines of force

C. magnetomotive force

D. lines of reluctance

19. Which two values are plotted on a B-H curve graph?

A. reluctance and flux density

B. permeability and reluctance

C. magnetizing force and permeability

D. flux density and magnetizing force

20. What is the number of turns required in the secondary winding for a transformer when 120 volts is applied to a 2400-turn primary to produce 7.5 Vac at the

secondary? A. 75 turns B. 150 turns C. 900 turns D. 1920 turns Answer: Option B

21. The four factors determining inductance are the number of turns, coil length, coil area, and:

A. Permeability

B. Reluctance

C. counter emf

D. coefficient of coupling

22. What is the inductive reactance if the Q of a coil is 60, and the winding resistance is 5 ?

A. 0.083

B. 12

C. 30

D. 300

23. The time difference, or lag, between flux density and magnetizing force is known as:

A. eddy current

B. magnetic saturation

C. Hysteresis

D. Coercivity

24. A magnetic circuit breaker will open to protect equipment only when:

A. voltage is exceeded

B. an open is in the equipment

C. the equipment is operating properly

D. current is exceeded

25. Electromagnetic induction is the generation of:

A. electricity from magnetism

B. electricity from electricity

C. magnetism from electricity

D. magnetism from magnetism

26. Inductance is:

A. directly proportional to the length of the coil

B. directly proportional to the number of turns on the coil

C. inversely proportional to the cross-sectional area of the coil

D. inversely proportional to the permeability

27. Current will cause a magnetic field in a conductor as follows:

A. An ac current causes a fixed polarity magnetic field.

B. A dc current causes a fixed polarity magnetic field.

C. A dc current causes an alternating magnetic field.

D. An ac current causes a fixed polarity magnetic field and a dc current causes an alternating magnetic field.

(32)

28. What is the total inductance, assuming no mutual inductance? A. 12 mH B. 6 mH C. 0.73 mH D. 0 mH Answer: Option A

29. During a current change, the ability of a conductor to produce counter emf within itself is called:

A. back emf B. self-induction C. a henry D. impedance Answer: Option B 30 .

If the switch is moved to position 1 in the given circuit, how long will it take for the current to reach its maximum value? A. 72.5 s B. 532 s C. 610 s D. 833 s Answer: Option B

31. When a transformer secondary lead has been

connected to a middle loop that is not an end connector, it is called a:

A. multiple-tapped secondary

B. center-tapped secondary

C. multiple winding secondary

D. single winding secondary

32. A 24 V peak source is connected across a 900 H inductor. If the frequency of the source is 22 kHz, what is the reactive power?

A. 2.3 VAR

B. 4.6 VAR

C. 9.3 VAR

D. 0 VAR

33. What is the permeability of machine steel?

A. 1.1 x 10−4

B. 5.65 x 10−4

C. 6.9 x 10−3

D. 8.8 x 10−3

34. What will happen when an inductor's magnetic field collapses?

A. Current will double.

B. Voltage will be induced.

C. A new field will expand.

D. Counter emf will be high.

35.

With a square wave input, an RL differentiator circuit with an output across the inductor will produce what type of waveform?

A. dc

B. short time-duration pulses

C. exponential-shaped pulses

D. only a phase shift

(33)

A. 0 s B. 5 s C. 15 s D. 25 s 37. Find VR and VL. A. VR = 41.6 V, VL = 78.4 V B. VR = 48 V, VL = 110 V C. VR = 56 V, VL = 106 V D. VR = 60 V, VL = 60 V Answer: Option C

38. If 360 Vac is the output of a 300-turn secondary winding, what is the input voltage when the primary winding has 150 turns?

A. 2.4 Vac

B. 150 Vac

C. 180 Vac

D. 720 Vac

39. When a magnet enters a coil and a voltage is induced, the process is known as:

A. an alternation

B. self-inductance

C. counter emf

40. What term is used to describe the action of magnetic flux from one circuit that cuts across the conductors of another circuit? A. self-inductance B. rectification C. mutual inductance D. magnetism Answer: Option C

41. Reactance in an inductive circuit will:

A. increase with frequency

B. decrease with frequency

C. be independent from frequency

D. depend on the value of XC

42. A turns ratio of 5 for a transformer implies:

A. more primary turns than secondary turns

B. more secondary current than primary current

C. larger source impedance than load impedance

D. more secondary turns than primary turns

43. A practical inductor

A. has inductance

B. has winding resistance

C. has winding capacitance

D. all of the above

44. When current in an inductor starts to change, it cannot react instantly due to:

A. fixed coil resistance

B. eddy current generation

C. applied emf of the circuit

D. the counter emf of the coil

(34)

400 mA of inductor current, when R = 10 ohms and L = 20 H? A. 10 seconds B. 8 seconds C. 4 seconds D. 2 seconds Answer: Option A

46. A utility pole transformer used to supply a residential customer with two phases uses:

A. two phases on the primary

B. a center tap on the secondary

C. a separate ground for each phase

D. a small coefficient of coupling

47. What is the inductive reactance?

A. 5.2

B. 7.5

C. 1.3 k

D. 7.5 k

48. When a coil collapses the induced circuit current will:

A. be in the same direction

B. go to zero

C. aid counter emf buildup

D. be in the opposite direction

49. When a rate of one ampere per second causes an induced voltage of one volt, the unit of measure is

A. a lenz

B. an ohm

D. a henry

50. If you wanted to decrease the inductance of a coil, you might increase the:

A. number of turns

B. permeability of the core

C. spacing between turns

D. area of the coil

51. The output phase for a transformer is:

A. in phase with the input

B. out of phase with the input

C. dependent on the direction of the primary and secondary windings

D. dependent on the frequency of the primary source

52. Opposition to current flow without the dissipation of energy is called: A. resistance B. inductive reactance C. counter emf D. impedance Answer: Option B

53. With 100 Vac applied to the primary of a transformer so that it draws 500 mA, what will be the 300

Vac secondary current? A. 1500 mA B. 200 mA C. 167 mA D. 150 mA Answer: Option C

54. Which coil would be used as a step-up transformer primary if coil number 1 has 100 more turns than coil number 2?

A. The coil windings must be the same.

B. coil 1

C. The coil ratio is too small.

D. coil 2