101 Important Electrical, Electronic and Control Systems Interview Q & A
1. An important quantity which is useful in circuit analysis is known as conductance G (Siemens). Which of the formulas A to D expresses the conductance for this circuit?
A. G = 1 / R
B. G = 2 R
C. G = I / R
D. G = R * V
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2. In terms of instrumentation and measurement, what is an I/P Transducer?
A. A transducer that converts a known electric current to a
pressure proportional to the current.
B. A transducer that increases a pressure signal which is too low
to give the desired effect.
C. A transducer that is inverting a pressure signal.
D. A transducer that converts a pressure to a proportional electric signal.
3. Measuring instruments must be routinely calibrated. What is the meant by instrument calibration?
A. Comparing input and output values against a documented standard
B. Comparing two instruments of the same type
C. Adjusting size to fit process connection
D. Turning gauge too an easy reading position
4. Thermistors are temperature sensitive devices. A positive temperature coefficient thermistor
will typically have
A. Relatively non linear characteristic
B. Relatively linear characteristic
C. Inaccurate measurement
D. Variable reliability
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5. This block diagram illustrates an elementary control system. What is the common name for this type of system?
A. Closed loop feed back system
B. Open loop feed back system
C. Feed forward system
D. Scmitt trigger
6. Transducers are devices which translate the value of one measured value into diferent measurement units (for instance units of temperature to millivlots). What is the meant by the “Range” of a transducer?
A. The difference between possible maximum and minimum measurement
B. The maximum output signal
C. The type of measurement
D. The maximum length of the connecting leads
7. What is a ZENER BARRIER?
A. A zener barrier is a unit made to obtain intrinsic safety in installations for instrumentation in hazardous areas.
B. A zener barrier is a device which limits the current drawn byan induction motor.
C. A zener barrier is a diode bridge used in rectifiers.
D. A zener barrier is a device that allows the current to pass only one direction.
8. What is the resistance value of this resistor:
A. 10 k ohm
B. 230 k ohm
C. 2,3 k ohm
D. 68 k ohm
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9. What type of component does this graphical symbol illustrate?
A. Pressure-reducing regulator.
B. Pressure relief valve
C. Pressure switch
D. Flow controller
10. What will be the probable outcome, if the amplification is set too high on a
temperature controller?
A. The process will oscillate and get out of control
B. Nothing
C. The process response will be very slow
D. The set-point will change
11. Which component does this graphical symbol illustrate?
A. Pressure indicator, installed on panel/console
B. Pressure instument, installed locally
C. Pressure relief valve, self-contained
D. PH analyzer
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12. Which of the following instruments is normally part of a control-loop?
A. Transducer
B. Indicator
C. Plotter
D. Gauge
13. Which of the following systems will include a D/P transmitter in the control-loop
A. Pressure
B. Temperature
C. Smoke indication
D. Oil mist
14. Why is it important that a transmitter has been correctly installed at the correct location
A. The control system is depending on the best possible process signal
B. It is important to have easy access to the transmitter for maintenance
C. It must be easy to observe for troubleshooting
D. Can be installed anywhere in the piping system
15. A resistor has three red bands. If they all carry information about
resistance value as opposed to tolerance, what is the indicated resistance?
A. 2200 ohm
B. 22 ohm
C. 222 ohm
D. 220 ohm
16. A thermistor may be used to measure temperature. Which of the following
descriptions most accurately describes this device?
A. Temp sensitive semi-conductor
B. Junction of two dissimilar metals
C. Capacitance probe
D. Platinium wire resistor
17. During routine checking of alarm functions of main and auxiliary
equipment, some setpoints are cancelled due to a mistake. What is the
appropriate routine to ensure correct setpoints are set?
A. Consult with the instruction manual for the equipment in
question for correct values.
B. Ask your colleague if he remembers the correct setpoint
C. Check from previous records for correct values
D. Select a setpoint based on present condition allowing for a
reasonable safety margin.
1210
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18. In installations of INTRINSICALLY SAFE equipment it is required that all cabling should
be separated from non-intrinsically safe equipment, and (where colour coding is relied upon) to
be of a special colour. What colour is that?
A. Blue
B. Green/yellow
C. Red
D. Orange
19. In measurement systems there is often a need to specify performance characteristics. One
such characteristic may be referred to as 'dead band'. What is the definition of DEAD BAND?
A. The change needed in the input signal to produce a change in the output signal.
B. The change in the output signal produced by a certain change in the input signal.
C. The largest difference in the output signal for the same change in the input signal.
D. A missing electrical signal with no output.
20. In measurement systems, which of the listed sensors is suitable for physical displacement?
A. Strain gauge
B. Thermocouple
C. Thermistor
D. Pt 500
21. In terms of electronic hardware, what is the meaning of the abbreviation PCB?
A. Printed Circuit Board
B. Power Control Bridge
C. Positive Colour Board
D. Positive Current Biased
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22. In terms of instrumentation and measurement, what is a digital signal?
A. A signal with discrete levels such as 0 = "low" and 1 = "High"
B. A signal indicating Revolutions per minute (RPM)
C. A signal used by multimeters to measure resistance.
D. The reading of a multimeter when indicating voltage, current or resistance.
23. It is common practice to connect a resistor over an alarm contact (see diagram) in many
applications. Why is this connection used?
A. To monitor the cable/wires for break.
B. To avoid sparks on the contacts when opening and closing.
C. To stabilise power consumption.
D. Enable measuring the total resistance of the circuit.
24. Measurement and transmission of electronic values may be in the form of
digital or analogue signals. What is an analogue signal?
A. A continually variable electric signal.
B. A measure of electric current or voltage
C. A measure of voltage using an oscilloscope.
D. A stable electric signal.
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