Penn Foster 08602701, 00290201, 07900200

Penn Foster 08602701

You wish to measure the AC value of a composite signal made up of both AC and DC voltages. The coupling switch should be set to
A. AC. C. GND.
B. DC. D. EXT.

2. You need to use an oscilloscope to measure an industrial control system that doesn’t contain a
ground reference. Which of the following actions should you take?
A. Connect the ground lead of the probe to the chassis and perform your measurements.
B. Hook the ground lead to the negative terminal of the power supply before performing measurements.
C. Isolate the oscilloscope from ground by using an Isolation Transformer.
D. Don’t use the ground lead on the probe, simply make measurements using the hook tip.

3. The amount of phase shift between input and output signals is important when measuring
A. SCR circuits. C. transistor circuits.
B. TRIAC circuits. D. servo circuits.

4. Your oscilloscope’s test probe is placed in the 10X or 10:1 position. You measure a waveform as being
4 VAC peak-to-peak. What is the actual voltage at this test point?
A. 0.04 VAC C. 4 VAC
B. 0.4 VAC D. 40 VAC

5. In a CRT, the direction of electron beam deflection depends on the
A. type of inert gas that the tube contains.
B. amount of voltage that’s applied to the deflection plates.
C. size of the screen.
D. polarity of the voltage that’s applied to the deflection plates.
6. To increase the vertical size of a 2 V square waveform that appears only one-half division high on
your scope screen, you should adjust the
A. vertical position control. C. time base control.
B. volts per division control. D. coupling switch to ADD.

7. The output signal from a frequency inverter will appear on a scope screen as a
A. pure sine wave of different frequencies.
B. triangular-shaped waveform with distorted peaks.
C. distorted square wave.
D. distorted sine wave.

8. An AC voltage that’s present on a DC power supply’s output is called
A. distortion. C. oscillation.
B. ripple. D. flicker.

9. Why should you use caution when measuring high-voltage inductive devices with an oscilloscope?
A. If the device shorts, a large current spike could destroy the probe.
B. The device may not be grounded.
C. The device can produce a very high voltage spike when it de-energizes.
D. High-voltage inductive devices produce electrical noise that can be displayed instead of the actual
waveform.

10. The connector that’s used to attach a probe to an input terminal of a scope is called a(n)
A. F-type connector. C. Phono style connector.
B. T-type connector. D. BNC connector.
11. If you’re preparing to make a measurement with a scope and you notice that the trace appears blurry
and distorted, which of the following controls should you adjust?
A. The focus adjustment C. The level adjustment
B. The slope control D. The coupling switch

52 Examination

12. The deflection plates in a CRT are operated by a varying
A. current. C. power.
B. resistance. D. voltage.
13. Which one of the following triggering controls is used to select the positive-going or negative-going
edge of a signal for trace triggering?
A. The level control C. The line control
B. The slope control D. The field control

14. What is the maximum AC input voltage (peak-to-peak) that most oscilloscopes can safely measure?
A. 600 V−800 V C. 1,000 V−1,400 V
B. 800 V−1,000 V D. 1,600 V−1,800 V

15. Which of the following scope probe connections should be used to make a measurement from an integrated circuit lead?
A. An extender on the probe C. A direct probe connection
B. A point-type probe contact D. A needle-tip probe

16. A sine wave signal takes 0.01 second to complete one cycle. What is the frequency of this signal?
A. 60 Hz C. 100 Hz
B. 80 Hz D. 120 Hz

17. What is the duty cycle of a square wave that’s positive for two horizontal divisions and at zero volts
for four horizontal divisions?
A. 25 percent C. 45 percent
B. 33 percent D. 65 percent

18. What is the peak-to-peak voltage of the AC waveform shown here if the volts per division control is set at 2 V per division?
A. 6 V peak-to-peak C. 10 V peak-to-peak
B. 8 V peak-to-peak D. 12 V peak-to-peak

19. A scope’s time base is set to 0.05 ms per division. An AC waveform takes five divisions to complete
one cycle. What is the frequency of the signal?
A. 4 kHz C. 8 kHz
B. 6 kHz D. 10 kHz

20. What is the frequency of an AC signal that takes 50 µs to complete one cycle?
A. 200 Hz C. 12 kHz
B. 2 kHz D. 20 kHz

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Penn Foster 00290201

1.   Look at the circuit illustrated in Figure A-1. Assume that the values of R1 and R2 are equal. If you connect your meter’s test probes to points A and B in the circuit, which of the following voltages would you measure?
A. 9 V
B. 6 V
C. 3 V
D. 0 V

2.   In the circuit shown in Figure A-1, where would you connect your meter’s test probes to measure the full battery voltage?

A. To points D and E, or to points B and E
B. To points A and C only
C. To points D and E, or to points A and C
D. To points B and E only

3.   In the circuit shown in Figure A-1, suppose that the value of R1 is 100 kW and the value of R2 is 470 kW. At which of the following locations in the circuit would you measure the highest voltage with your meter?
A. Between points A and C
B. Between points A and B
C. Between points B and C
D. Between points B and E

4.   In the circuit shown in Figure A-1, suppose that the value of R1 is 500 kW. In order to obtain a multimeter reading of 1 V between points B and C in the circuit, the value of R2 would have to be
A. 10 kW.
B. 100 kW.
C. 1,000 kW.
D. 10,000 kW.

5.   Imagine that you’ve properly connected your multimeter into an operating circuit, and the meter’s function/range switch is set to read DC voltage in the 20 V range. The meter displays a “1” in the most significant digit position. This indicates that
A. the meter measured a voltage of 1 V at the point under test.
B. the power to the circuit is turned off.
C. the voltage at the point under test is greater than 20 V.
D. the function/range switch should be set to the next lowest range.

6.   Silver has the highest conductivity rating of any common metal. Which of the following correctly ranks metals in decreasing levels of conductivity?
     A. Silver, zinc, gold, platinum
B. Silver, copper, aluminum, lead
    C. Silver, gold, nickel, mercury
     D. Silver, copper, gold, aluminum

FIGURE A-2—Use this illustration to answer Questions 7, 8, 9, and 10.

7.   Look at the circuit shown in Figure A-2. Switch S1 is open as shown, and R1 and R2 each have a value of 100 kW. If you connect your meter’s test probes to points A and B in the circuit, what voltage would you measure?
A. 9 V
B. 6 V
C. 3 V
D. 0 V

8.   For the circuit shown in Figure A-2, the correct procedure for measuring the resistance value of R1 is to
A. connect the multimeter between points C and D and measure the resistance with switch S1 open.
B. connect the multimeter between points C and D and measure the resistance with switch S1 closed.
C. connect the multimeter between points D and A and measure the resistance with switch S1 open.
D. connect the multimeter between points D and A and measure the resistance with switch S1 closed.

9.   You’re using your meter to make voltage measurements in the circuit shown in Figure A-2. Your meter is connected between points A and C, and you’re getting a reading of 6 V on the display. What can you conclude from this reading?
A. Switch S1 is open.
B. Resistor R2 has a resistance value that’s twice the value of either R1.
C. Switch S1 is closed.
D. Resistors R1 and R2 have equal resistance values.

10.   In the circuit shown in Figure A-2 where R1 and R2 have equal resistance values, when switch S1 is closed, what voltage would you measure across R2 with your meter?
A. 0 V
B. 1 V
C. 3 V
D. 6 V

11.   What important safety precaution must be observed when measuring resistance in an electronic circuit?
A. All power to the component under test must be disconnected.
B. The meter’s highest resistance range setting should be used until the actual value is determined.
C. The black test lead must be connected to the chassis ground.
D. The red test lead must be at the most positive point in the circuit.

FIGURE A-3—Use this illustration to answer Questions 12, 13, 14, and 15.

12.   Look at the circuit shown in Figure A-3. With switch S1 closed, you’re making voltage measurements with your meter. Assume that each of the four resistors has a resistance value of 100 kW. You measure 3.6 V across resistor R1, 1.2 V across resistor R2, 1.2 V across resistor R3, and 2.4 V across resistor R4. What is the battery voltage in the circuit?
A. 10 V
B. 6 V
C. 4 V
D. 2 V

13.   Again, assume that each of the resistors in the circuit shown in Figure A-3 has a resistance value of 100 kW. With switch S1 open as shown, you measure the voltage across each resistor with your meter. Which of the following statements is correct?
A. Resistors R1, R2, and R3 will dissipate equal amounts of power.
B. Resistor R1 will dissipate the most power.
C. Resistors R4 and R1 will dissipate equal amounts of power.
D. Resistor R3 will dissipate the most power.

14.   Assuming that each of the resistors in the circuit shown in Figure A-3 has a resistance value of 100 kW, what will be the total resistance of the circuit with switch S1 closed?
A. 100 kW
B. 167 kW
C. 280 kW
D. 400 kW

15.   Assuming that each of the resistors in the circuit shown in Figure A-3 has a resistance value of 200 kW, which resistor will dissipate the most power?
A. R4
B. R3
C. R2
D. R1

FIGURE A-4—Use this illustration to answer Questions 16, 17, 18, 19, and 20.

16.   Look at the circuit shown in Figure A-4. The circuit contains a 6 V battery and three resistors. Four meters are being used to make measurements in the circuit. Meters M1, M2, and M3 are being used to measure current at different points in the circuit. Meter M4 is being used to measure voltage at another point in the circuit. With S1 closed, M1 has a current reading of 0.04A. What will be the total resistance in this circuit?
     A. 50 W
B. 100 W
    C. 150 W
     D. 300 W

17.   With switch S1 closed, meter M4 reads 4 V across R3. What voltages would the meter read across R1 and R2?
A. The meter would read 2 V across R1 and 2 V across R2.
B. The meter would read 1 V across both R1 and R2.
C. The meter would read 4 V across R1 and 4 V across R2.
D. The meter would read 4 V across both R1 and R2.

18.   With switch S1 closed and the resistance value of R1 and R2 equal, meter M1 has a current reading of 0.04 A. What will be the current readings on meter M2 and meter M3?
A. Meter M2 and meter M3 will both read 0.1 A.
B. Meter M2 will read 0.2 A, and meter M3 will read 0.4 A.
C. Meter M2 and meter M3 will both read 0.04 A.
D. Meter M2 will read 0.02 A, and meter M3 will read 0.02 A.

19.   In the circuit shown in Figure A-4, suppose that meter M3 displays a higher current reading than it should. Which of the following could be the cause of this condition?
A. Resistor R1 is shorted.
B. Resistor R3 is open.
C. Resistor R2 is shorted.
D. Switch S1 is open.

20.   What will be the total power dissipated in the circuit shown in Figure A-4?
A. 0.24 W
B. 1.5 W
C. 24 W
D. 150 W

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Penn Foster  07900200

1. How should the selector switch be set when checking a resistive element coil for continuity?

2. When an AC voltage is being measured across a 15 Ω resistor which is carrying a current of 12 amps, the selector switch should be set to the AC voltage position of

3. If the function/range switch is set at 200 VAC, what will the multimeter read if a measurement is made directly across both terminals of a good fuse or circuit breaker in a 120 VAC line?

4. If the function/range switch is set at 200 VAC, what will the multimeter read if a measurement is made directly across both terminals of a blown fuse or tripped circuit breaker in a 120 VAC line?

5. Determine the current in a circuit consisting of a 1000 ohm resistor with a voltage of 50 volts DC across it.

6. When measuring an unknown DC voltage with your multimeter, you should first
B. set your selector switch to the highest DC voltage range and then decrease to the range that will give you the most accurate reading.

7. The multimeter for this manual can measure resistances up to about

8. The main reason why you should avoid bodily contact with ground while working on live electrical equipment is that such contact will

9. Calculate the resistance of a circuit that draws 10 amps at a voltage of 120 volts.

10. Calculate the power (P) in watts dissipated by a resistor of 1000 ohms with 200 volts across it.

11. To measure an unknown line voltage at an electrical outlet,

12. Assume that the function/range switch is on the 20 kΩ position and the multimeter displays “1” when the test leads are across an unknown resistor. What would most likely cause the meter to display “1” ?
B. The function/range switch not set on a high enough scale

13. When measuring current, always place the meter in

14. Assume a device draws 50 mA of current and 150 VDC

15. What precaution should be observed when the multimeter isn’t being used?

16. When working with electricity, the electrician should make a practice of

17. When is the Common jack on the front panel used?

18. If an appliance draws 10 amps and the line voltage is 110 volts, the power consumed is

19. A circuit whose resistance is 22 Ω and has an applied voltage of 440 volts will draw a current of

20. If an appliance is plugged in but the switch is OFF, the electrician should always consider the appliance as