Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Which of the following devices changes resistance inversely with the temperature?
1)
A)
thermocouple
B)
thermistor
C)
triac
D)
RTD
2)
What affects the accurate operation of a resistance bridge measuring temperature?
2)
A)
ambient temperature
B)
input voltage
C)
length of wires going to the detector
D)
all of the above
3)
Voltage storage in a sample and hold amplifier is accomplished by:
3)
A)
the output buffer op–amp.
B)
a JFET switch
C)
a holding inductor.
D)
a holding capacitor.
4)
Precise control of a triac to prevent high–frequency transients is called:
4)
A)
pulse switch triggering.
B)
negative feedback biasing.
C)
microcontroller pulsing.
D)
zero–voltage switching.
5)
One method of providing an accurate thermocouple interface is:
5)
A)
to use a swamping resistor.
B)
to use a reference voltage in the feedback circuit.
C)
to use a reference thermocouple.
D)
capacitive coupling.
1
6)
Since the triac can be triggered to allow current to flow both directions, it can be used in:
6)
A)
ac circuits.
B)
phase control.
C)
dc circuits.
D)
any of the above.
7)
Basic analog physical parameters such as angular position, temperature, pressure, strain, and flow
rate can be measured by what devices?
7)
A)
Transmitters
B)
Transmissions
C)
Transducers
D)
Telemeters
A
8)
A device that exhibits a change in resistance based on a change in pressure is called a:
8)
A)
psi gauge.
B)
gauge transducer.
C)
pressure transducer.
D)
none of the above.
C
9)
Circuits that contain features such as common–mode rejection, isolation, gain, etc. are called:
9)
A)
signal conditioners.
B)
thermocouples.
C)
interfaces.
D)
none of the above.
A
10)
What device is formed by adjoining two dissimilar metals?
10)
A)
pop–sensor
B)
thermocouple
C)
sequencer
D)
none of the above
B
2
D
11)
An input transducer converts:
11)
A)
a nonelectrical quantity to an electrical quantity.
B)
voltage to current.
C)
current to voltage.
D)
an electrical quantity to a nonelectrical quantity.
12)
Which of the following components is not used as a temperature measurement device?
12)
A)
RTD
B)
triac
C)
thermocouple
D)
All are used to measure temperature changes.
13)
A cold–junction:
13)
A)
can have an unpredictable effect on the thermocouple effect.
B)
opposes measured temperature.
C)
has a value that depends on ambient temperature.
D)
all of the above.
14)
Which of the following is not a temperature sensor?
14)
A)
thermocouple
B)
triac
C)
resistance temperature detector
D)
thermistor
15)
The quantity usually measured using a spring–supported seismic mass is:
15)
A)
acceleration.
B)
volume.
C)
weight.
D)
velocity.
3
16)
What quantity indicates change in positions of a body or point?
16)
A)
motion coefficient
B)
relative velocity
C)
FIFO
D)
displacement
17)
Sample and hold circuits:
17)
A)
increase resolution.
B)
convert analog voltages to a binary number.
C)
reduce quantization error.
D)
all of the above.
D
18)
The ac value that is equal to the same dc heating effect is usually called:
18)
A)
peak value.
B)
rms value.
C)
heat value.
D)
average value.
B
19)
Which of the following ADC circuits has the highest resolution?
19)
A)
4 bit
B)
one that has the highest aperture time
C)
16 bit
D)
none of the above
C
20)
The deformation of a material due to force acting on it is called:
20)
A)
compression.
B)
pressure.
C)
stress.
D)
strain.
D
4
D
21)
One common method of measuring flow rate of a fluid through a pipe is the:
21)
A)
wein–bridge method.
B)
hall effect.
C)
differential pressure method.
D)
dynaflow method.
22)
Which of the following is not a force–related parameter?
22)
A)
strain
B)
motion
C)
velocity
D)
pressure
23)
What device has the same function as a thermocouple but has a more linear output?
23)
A)
analog temperature device
B)
capacitive temperature detector
C)
linear temperature device
D)
resistance temperature detectors
24)
The device often used as an electronic switch in many applications is the:
24)
A)
diode.
B)
SPDT.
C)
SPST.
D)
SCR.
25)
Displacement transducers make use of which of the following?
25)
A)
light
B)
capacitance
C)
magnetism
D)
any of the above
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
26)
Strain gauges are used to detect minute changes in temperature.
26)
5
Explanation:
27)
Pressure sensors make use of an RTD for their operation.
27)
28)
A triac must be triggered for each alternation for proper operation.
28)
29)
Displacement transducers can be made using a variety of types of optical or electrical circuits.
29)
30)
Analog–to–Digital conversion takes a specific analog quantity and produces a unique binary
number to represent that quantity.
30)
31)
RTDs and thermistors both operate on the same principle of resistive change with temperature.
31)
32)
The typical output for a normally operating thermocouple is in the range of 1 V to 10 V.
32)
33)
Conversion of analog signals to digital signals is common in most controlled industrial processes.
33)
34)
The aperture time for a sample–and–hold circuit refers to the change in the voltage from the
sampled value during the hold interval time.
34)
35)
A SCR is used mainly in the control of AC circuits.
35)
6
Answer Key
Testname: C21
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