Encoded by: Engr. Aldous Brian M. Mantiza, ECT, ECE
1. The instrument most widely used for testing of semiconductor diodes is. a. Voltmeter b. Ammeter c. Ohmmeter d. Oscilloscope 2. An 8-Volt relay is used with a 12 -Volt power supply. The relay requires a current of 0.1 Amp. What is the series resistance required? a. 40 ohm b. 480 ohm c. 120 ohm d. 80 ohm 3. What is the meaning of the abbreviation of PCB? a. Printed Circuit Board b. Positive Colour Board c. Power Control Bridge d. Positive Current Biased 4. The maximum current that a 15 Volt, 3 Watt Zener diode can handle without damage is? a. 20 A b. 0.5 A c. 0.45 A d. 0.2 A 5. What principle of measurement is the viscosity controller based on? a. Measurement of differential pressure b. Measurement of flow c. Measurement of two different temperatures d. Measurement of temperature 6. When we are using a diode to convert AC to DC, it is usually referred to as a a. Controller b. Regulator c. Rectifier d. Alternator 7. The typical current gain of a common emitter transistor is a. 10-200 b. 1-10 c. 50-5000 d. 1-1000 8. The inductance which will induce an EMF of 1 Volt in a conductor when the current is changing at a rate of 1 Amp per second, is defined as? a. Microfarad b. Henry c. Millihenry d. Farad
9. What kind of electrolyte is used for Nickel-iron batteries? a. Solution of zinc-carbon and water b. Solution of sulphuric acid and water c. Solution of potassium hydroxide (KOH) and water d. Solution of sodium and water 10. How can we check if a lead –acid –acid type battery is fully charged or not? a. Measure the level of the electrolyte b. Measure the specific gravity of the electrolyte c. Measure the temperature of the electrolyte d. Measure the voltage 11. The circuit consists of two inductors, L(1) = 6H and L(2) = 12H, connected in parallel. Calculate t he equivalent L(S) of two inductors. a. 18H b. 1.5H c. 0.5H d. 4H
12. The circuit consists of two inductors, L(1) = 6H and L(2) = 12H, connected in series. C alculate the equivalent L(S) of two inductors. a. 18 H b. 4 H c. 1.5 H d. 2 H 13. The circuit consists of two capacitors, C(1) = 6uF and C(2) = 12uF, in parallel. Calculate t he equivalent C(S) of the two capacitors. a. 4uF b. 2uF c. 18uF d. 1.5uF 14. The circuit consists of two capacitors, C(1) = 6uF and C(2) = 12uF, in series. Calculate the equivalent C(S) of the two capacitors. a. 4uF b. 2uF c. 18uF d. 1.5uF 15. This circuit consists of two resistances, R1 = 6 ohm and R2 = 12 ohm, connected in series. Calculate the equivalent resistance R(S) of the two resistances? a. 18 ohm b. 2 ohm c. 4 ohm d. 1.5 ohm
16. This circuit consists of two resistances, R1 = 6 ohm and R2 = 12 ohm, connected in parallel. Calculate the equivalent resistance R(S) of the two resistances? a. 18 ohm b. 2 ohm c. 4 ohm d. 1.5 ohm 17. Which function is this operational amplifier circuit performing? a. Integrator b. Non-inverting amplifier c. Inverting amplifier d. Differentiator
18. Which function is this operational amplifier circuit performing? a. Non-inverting amplifier b. Differentiator c. Integrator d. Inverting amplifier
19. Which function is this operational amplifier circuit performing? a. Integrator b. Non-inverting amplifier c. Inverting amplifier d. Differentiator
20. Which function is this operational amplifier circuit performing? a. Non-inverting amplifier b. Differentiator c. Integrator d. Inverting amplifier
21. Which function is this circuit performing? a. Telemetering b. Modulating c. Differentiating d. Integrating
22. This circuit consists of a current source I, a change-over switch S, a resistor R and an inductor L. The voltage/time figures 1 to 4 show possible changes through L if the switch S is suddenly shifted from position 1 to 2 at time t = 0. Only one of the diagrams is co rrect. Which? a. Figure 3 b. Figure 1 c. Figure 2 d. Figure 4
23. This circuit consists of a current source I, a change-over switch S, a resistor R and a capacitor C. The current/time figures 1 to 4 show possible changes in the current I in case the switch S is suddenly shifted from position 1 to 2 at time t =0. Only one of the diagrams is correct. Which? a. Figure D b. Figure A c. Figure C d. Figure B
24. This circuit consists of a voltage source V, a change-over switch S, a resistor R and a capacitor C. The voltage/time figures 1 to 4 show possible changes in the voltage V(C) in case t he switch S is suddenly shifted from position 1 to 2 at time t = 0. Only one of the diagrams is correct. Which? a. Figure 1 b. Figure 2 c. Figure 3 d. Figure 4
25. What is digital signal? a. Signal indicating voltage b. A signal indicating Revolution per minute (RPM) c. A signal indicating ampere d. A signal representing 0 = “low” and 1 = “High” 26. What is an analogous signal? a. A variable electric signal b. A measure for voltage c. A stable electric signal d. A measure for electric current
27. A resistor has three red bands. bands. What is the resistance? a. 2200 ohm b. 220 ohm c. 22 ohm d. 222 ohm 28. What is the resistance value of t his resistor? a. 230 kohm b. 2.3 kohm c. 68 kohm d. 10 kohm 29. The physical size of a resistor is an indicator of its: a. Tolerance b. Resistivity c. Total resistance d. Power dissipation capability 30. This resistor has the value of 68 kohm. Which co lor code will you put on the different color-kings? a. Red black yellow b. Violet green yellow c. Black red orange d. Blue gray orange 31. The picture shows a common used 3.5 inches diskette t ype for storing data. What is the data storing capacity for such diskette? a. 1.44 MB b. 760 kB c. 20 MB d. 540 kB 32. Which electronics component or system of components is this graphical symbol illustrating? a. Battery charger b. Low pass filter c. Inverter d. Auto transformer 33. Which electronic component or system of components is t his graphical symbol illustrating? a. Bandpass filter b. 3-phase sine-wave generator c. Electric heater d. Transformer with ferromagnetic core 34. Which electronic component or system of components is t his graphical symbol illustrating? a. Cathode ray tube b. Electronic counter c. Flip-flop d. Operational amplifier
35. Which electronic component is this graphical symbol illustrating? a. Zener diode b. Triac c. Transistor d. Silicon controlled rectifier 36. The figures show a graphical symbol for a particular electronic component and a typical working characteristic for the same component. Which component? a. Silicon controlled rectifier (SCR) b. Tunnel diode c. Zener diode d. Field effect transistor
37. The figures show a graphical symbol for a particular electronic component and a typical working characteristic for the same component. Which component? a. Zener diode b. Tunnel diode c. Field effect transistor d. Triac
38. The figure shows a silicon controlled rectifier with a RC circuit connected in parallel. RC circuit is often used in such c onnection. For which purpose? a. Protect the SCR against damage caused by high voltage spikes b. Obtain current resonance c. Measuring the current through the SCR d. Delay the ignition of the SCR
39. Diodes are widely used in rectification, or the conversion of alternating current to direct current. This circuit symbol is such example. The input voltage V(in) is sine-wave AC. Which of the shown output voltages is correct for this circ uit? a. Figure 3 b. Figure 2 c. Figure 1 d. Figure 4 40. The circuit symbol is a widely used system for r ectification of AC into DC. Which of the diagrams is the correct for the output voltage when the input voltage is sine-shaped as shown? a. Figure 1 b. Figure 2 c. Figure 3 d. Figure 4
41. The circuit symbol is a full-wave bridge rectifier. Which ele ctronic component will you connect between ‘a’ and ‘ b’ in order to obtain reduced ripple voltage to the load RL? a. Inductive reactor b. Resistance c. Zener diode d. Capacitor
42. Which of the 3 alternatives given is correct for a NOT-gate? a. Figure 1 b. Figure 2 c. Figure 3 d. None of the figures
43. Which of the 3 alternatives given is correct for an AND-gate? a. Figure 2 b. Figure 1 c. Figure 3 d. None of the figures
44. Which of the 3 alternatives given is c orrect for an OR-function? a. Figure 2 b. Figure 1 c. Figure 3 d. None of the figures
45. This graphical symbol is a logic gate. Which gate? a. NAND b. NOR c. AND d. OR
46. This graphical symbol is a logic gate. Which gate? a. NOR b. AND c. OR d. NAND 47. This graphical symbol is a logic gate. Which gate? a. AND b. NOR c. NAND d. OR
48. This circuit is a logic gate with two input signals, A and B, and one output signal Q. Which type of logic function is the gate giving? a. OR gate b. AND gate c. NOR gate d. NAND gate
49. This circuit is a logic gate with two input signals, A and B, and one output signal Q. Which type of logic function is the gate giving? a. AND gate b. NOR gate c. NAND gate d. OR gate
50. This circuit is a flip-flop. Which type? a. Bi-stable flip-flop b. Unstable flip-flop c. Schmitt trigger d. Mono-stable flip-flop
51. This is a parallel L-C circuit with curve showing frequency-impedance characteristics. Which of the formulas A to D will you utilize for determining the resonant frequency f? a. fo = 1/(2 sqrt (L/C)) b. fo = 1/(sqrt(1 - LC)) c. fo = 1/(sqrt(1 - LC)) d. fo = sqrt(L/C) / C
52. When paralleling two alternators they must have: a. Same number of phases b. Same frequency c. All of the mentioned alternatives d. Same phase rotation 53. The automatic voltage regulator is used to control the output voltage of the alternator at varying load conditions by: a. Varying the excitation field strength by regulating excitation voltage/current b. Supplying variable current to compounding and no load transformers in the alternator stator winding circuit c. All of the mentioned alternatives d. Regulating the voltage signal to the e ngine governor to regulate the speed to the desired load condition 54. At which point do you engage the m ain circuit breaker of the incoming alternator when paralleling two alternators? a. With the pointer of the synchronoscope rotating fast and both synchronizing lamps flashing on and off b. In none of the mentioned alternatives c. With the pointer of the synchronizer stopped at any position and both synchronizing lamps bright (on) d. With the pointer of the the synchronoscope at 0deg (12 O’clock) and both synchronizing lamps dark (off) 55. With two alternators operating in parallel at 75% load capacity, one trips without any warning. What is the first action that should be taken? a. Restart the tripped alternator immediately b. Start and connect the emergency alternator c. Check the circuit breaker of the tripped alternator d. Trip/stop all nonessential loads that are connected to the switchboard 56. With two alternators running in parallel, you wish to stop one. The first step is to: a. Trip the main circuit breaker b. Increase the frequency on the switchboard c. Remove the load from the alternator to be stopped d. Make sure the load is evenly shared 57. With no. 1 and no. 2 alternators running in parallel and the kW loads equally shared, one alternator is drawing much higher current that the other. o ther. What does this indicate? a. Alternator frequencies are different and should be adjusted on the governor speed controllers b. The alternators are not generating the same voltages and should be adjusted on automatic voltage regulator rheostats c. Alternators are out of phase and should be tr ipped and paralleled again d. One alternator has lost one of its phases 58. What determines the power factor of an alternator when it is connected singularly to the switchboard? a. The load connected to the switch board b. The excitation voltage c. The generated voltage d. Number of pairs of pole coils in the ex citation winding
59. A three phase alternator is connected c onnected singularly to the main switchboard. The switchboard instruments show 440 Volts/950 amperes. With a power factor of 0.8, what will be the kW load? a. 905 kW b. 579.2 kW c. 522.5 kW d. 334.4 kW 60. If you alter the field excitation voltage of one alternator operating in parallel, this will cause change in that alternators: a. Active load (kW) b. Reactive load (kVAR) c. Frequency d. None of the mentioned alternatives 61. You are paralleling two alternators and the pointer of the synchronoscope slowly rotating and remains stopped in one position before the circuit breaker is closed. This would indicate: a. The frequency of the incoming alternator is the same as that of the main switchboard b. The incoming alternator is in phase with the switchboard, but the frequency is not the same c. The voltage of the incoming alternator is the same as that of the main switchboard d. The synchronoscope is not functioning properly and should be checked. 62. Due to failure of one of the t he carbon brushes the excitation voltage is lost on o ne alternator that is operating in parallel. Will that alternator then: a. Overload due to reduced voltage output and increased curr ent b. Completely loose its share of the load causing t he auxiliary engine to speed up c. Try to take all the load and so trip the main circuit breaker d. Continue to share the active load (kW) but have very high reactive load (kVAR) 63. What is the purpose of the alternator reverse power trip? a. To prevent the alternator from being paralleled if it is out of phase with the m ain switchboard b. To give automatic disconnection of the circuit breaker whe n you are taking the alternator of the switch board c. To prevent parallel operation if the excitation field voltage is reversed d. To prevent the alternator from “motoring” by being supplied power from other parallel alternator 64. A 450 volt 3 phase brushless alternator will have the following combination of items mounted on the rotor: a. Excitation field winding/main field winding b. Excitation field winding/rectifier bank/main field winding c. 3 phase excitation winding/rectifier bank/main field winding d. 3 phase excitation winding/main field winding 65. A 450 volt, 859 kW rated generator has not been in operation for several weeks. Prior to starting, insulation resistance readings are taken. The minimum acceptable insulation resistance reading on the main stator winding to allow you to proceed with running the ge nerator is: a. 10 Ohms b. 10 000 000 Ohms c. 10 000 Ohms d. 1000 Ohms
66. The power requirements for the excitation winding/circuit for a 3-phase alternator operating at rated output power are supplied by: a. Independent power supply and rectifier unit b. The main switchboard via a three phase rect ifier c. The alternators output itself via the automatic voltage reg ulator d. Independent battery supply 67. You have just synchronized a second alternator onto the m ain switchboard, and want to equally share the load between the “on” and incoming alternators. What What would you do first? a. Lower the governor speed controller of the incoming alternator and increase the governor speed controller of the alternator already on the switchboard. b. Adjust voltage rheostat for the incoming alternator on t he front of the switchboard c. Trip the circuit breaker of the incoming alternator and check the voltage and speed adjustments before trying again d. Raise the governor speed controller of the incoming alternator and reduce the g overnor speed controller of the alternator already on the switchboard 68. Before taking insulation resistance readings of generator w indings the automatic voltage regulators should be isolated and all semiconductor short circuited or disconnected in order to: a. Prevent charging of capacitive components within the automatic voltage regulator causing false regulation when generator restarts b. Prevent damage to sensitive electronic components from high voltage tester c. Protect insulation resistance tester from being damaged d. Prevent operation of automatic voltage regulator during insulation testing
69. For which of the following systems would you install a PID-controller? a. Temperature-control b. Flow-control c. Gas measurement d. Pressure-control
70. In which of the following processes will the time constant be of minor importance. a. Pressure control b. Flow control c. Temperature control d. Level control
71. What is typical for a continuous control system? a. The output signal is equal to the input signal b. The control valve will always be changing position c. It is possible to predict the control co ntrol mathematically d. It is not possible to have a stable process
72. What will be the probable outcome if the amplification is set to high on the controller? a. The process will oscillate and get out o f control b. The set-point will change c. Nothing d. The process response will be very slow 73. What is typical for a P (proportional)-controller? a. Very stable control b. It will always be a deviation between the set-point and the process value c. Very reliable control and easy installation d. Simple maintenance 74. What is typical for a feed-forward control system? a. The process is always oscillating b. It is easy to obtain a perfect control c. We can calculate the system response mathematically d. We are controlling the process inlet side 75. What is proportional band? a. Amplification/10 b. Amplification/100 c. Any part of the total amplification d. 100/amplification 76. What is the most common type of controller? a. P-controller b. PID-controller c. PD-controller d. PI-controller 77. Which controller must be tuned first in a cascade control system? a. The primary controller b. The secondary controller c. Both at the same time d. Any one of them 78. What is the ideal relation between two following amplitudes on the response curve? a. 1:8 b. 1:4 c. 1:2 d. 1:16 79. What is dynamic amplifying? a. Variable amplifying b. Corresponding change in signals c. Amplitude of input signal divided by amplitude of output signal d. Amplitude of output signal divided by amplitude of input signal
80. What is static amplifying? a. Corresponding change in signals b. Change in output signal divided by change in input signal c. Change in input signal signal times change in output signal d. Change in input signal divided by change in output signal 81. Which of the following parameters will result in oscillation? a. Too long I-time b. Too high amplification c. Too short D-time d. Temperature change 82. Which of the following parameters will not result in oscillation? a. Too long I-time b. Too long D-time c. Temperature change d. Too high amplification 83. What is the meaning of the expression dead-band? a. It will take some time before the controller is reacting on a change b. The controller will not react on a process change in a specific range c. It will only react in a limited time d. It is not responding to adjustment of set -point 84. What is the definition of DEAD BAND? a. The change needed in the input signal to produce a change in the output signal b. A missing electrical signal c. The largest difference in the output signal for the same change in the input signal d. The change in the output signal produced by a certain change in the input signal 85. What is the meaning of split-range? a. Several control-valves are connected to the same controller b. On-Off control c. Several controllers are connected to the same control-valve d. Several control-loops for the same range 86. What is the influence of the I (integration) function of a controller? a. It will try to reduce the deviation between set-point and process value b. Very quick control c. Easy to change set-point d. It will slow down the control system 87. During routine checking of alarm functions of main and auxiliary equipment, some set points are cancelled due to a mistake. What will be the appropriate routine to ensure correct set points are set? a. Consult with the instruction manual for the equipment in question for corre ct values b. Select a set point based on o n present condition allowing for a reasonable safety margin c. Check from previous records for correct values d. Ask for colleague if he remembers the correct set point
88. The range of a transducer is 0-200 0 -200 bar. The standard output signal 4-20 mA. What is the output signal when the process value is 100 bar? a. 10 mA b. 12 mA c. 4 mA d. 24 mA 89. The range of a transducer is 0-200 0 -200 bar. The output signal 4-20 mA. What is the span of the output signal? a. 16 mA b. 12 mA c. 4 mA d. 24 mA 90. When we are measuring flow of fluids with a fixed area flow meter, t he name of the sensing device is: a. Turbine rotor b. Positive displacement rotor c. Float d. Orifice plate 91. When we are measuring level of liquids with a differential pressure meter, the name of the sensing device is? a. Pressure diaphragm b. Float c. Capacitance probe d. Positive displacement tube 92. When we are measuring level of o f liquids with a conductivity level indicator, the name of the sensing device is? a. Displacement probe b. Ionization chamber c. Electrodes d. Capacitance Probe 93. When we are measuring salinity with a salinometer, the sensing device is? a. Inductor capsule b. Capacitance probe c. Electrodes d. Strain gauge 94. When we are measuring viscosity with a restricted flow viscometer, the name if the sensing device is? a. Capillary tube b. Bourdon tube c. Capacitance probe d. Rotating cylinder 95. What is a typical problem when it is something w rong with the span of an instrument? a. Zero-point is accurate, but 100% input is not giving 100% output b. Zero-point and 100% are correct, but not 50% c. Linearity problems d. 100% output is accurate, but Ze ro-point is wrong
96. When you are calibrating an instrument what is the most common second step in the procedure (consult the manual)? a. Adjustment of range b. Adjustment of Zero-point c. Adjustment of span d. Check linearity 97. For any engine room operated in UMS-mode, defined checks are to be carried out prior to switching to UMSmode. Is it the Engineer on Duty’s responsibility to have the full full control of condition any check items prior to switching to UMS-mode and and leaving the engine room, room, or may he leave the engine? a. Ok for 15-20 minutes without a proper check b. Ok for a short period as long as one rating is left “on watch” c. A described UMS-mode check shall always be carr ied out prior to leaving the engine room, irrespective of the time he will be absent. d. Ok for one hour without a proper check 98. When you are calibrating an instrument what is the most common first step in the procedure (consult the manual)? a. Adjustment of range b. Adjustment of Zero-point and span c. Adjustment of span d. Adjustment of linearity 99. What precaution is to be taken when w hen the Engineer on Duty is entering an UMS-mode operated engine room due to an alarm or due to a scheduled routine check? a. Switch the UMS selector switch to manual mode and engage the “dead m an alarm” b. Leave the UMS selector switch in UMS-mode c. Any of the mentioned alternatives will meet the requirements d. Switch the UMS selector switch to manual mode only 100. In some cases we can see that a resistor is connected over an alarm contact (see diagram). Why is this connection used? a. To stabilise power consumption b. To avoid sparks on the contacts when opening and closing c. Enable measuring the total resistance of the circuit d. To monitor the cable/wire for break
101. What is this kind of controller normally called? a. A double acting controller b. A cascade controller c. A two point controller d. A two way controller
102. In a PID controller we have possibility to change the setting of the proportional band (P), the Reset time (I) and the t he Rate time (D). Please indicate which curve shows the typical response to a change in input, if the setting of the proportional band is too wide. a. Figure 3 b. Figure 1 c. Figure 4 d. Figure 2
103. In a PID controller we have possibility to change the setting of the proportional band (P), the Reset time (I) and the Rate time (D). Please indicate which curve shows t he typical response to a change in input, if the setting of the rate time is too short. a. Figure 3 b. Figure 1 c. Figure 4 d. Figure 2
104. In a PID controller we have possibility to change the setting of the proportional band (P), the Reset time (I) and the t he Rate time (D). Please indicate which curve shows the typical response to a change in input, if the setting of the rate t ime is too fast. a. Figure 3 b. Figure 1 c. Figure 4 d. Figure 2
105. Wheatstone Resistance Bridge is often used for measuring resistances in for instance Pt100 temperature sensors or strain gauges. This figure is such a bridge. What is the requirement for balance of such a bridge? i.e. the current t hrough the meter i(m) = 0. a. R1/R4 = R2/R3 b. R1+R3 = R2+R4 c. R1*R3 = R2*R4 d. R1/R2 = R3/R4 106. These circuit diagrams illustrate four different methods of wiring between a Pt-100 temperature sensor and its signal processing electronics. Which of the wiring methods gives the best measuring accuracy? a. Figure 2 b. Figure 4 c. Figure 3 d. Figure 1
107. Prior to the lunch break, the Engineer on Duty observes that the oper ating generator set has an output of 90%. With regard to operation of the generator, what is the – the –most most important- assumption(s) for him to check before switching to UMS-mode? a. All parameters as listed under the other alternatives b. Visually checking the auxiliary engine that there are no leaks or other operating failures c. That all operating parameters of the ge nerator set in operation are normal (e.g. exhaust temperatures, lube oil pressure, cooling water temperature, etc.) d. That a secondary auxiliary set is switched to automatic standby mode.
108. A transformer with 10:1 turns ration and rated 50 kVA, 2400/240 Volts, 60 Hz, is used to step down the voltage to a distribution system. The low tension voltage is to be kept constant at 240 Volts. What load impedance connected to the low-tension side will cause the transformer to be fully loaded? a. 2.3 ohms b. 1.15 ohms c. 115 ohms d. 230 ohms 109. During a routine sea passage the c ooling water high temperature alarm system for one of the auxiliary engines is out of function and blocked. What will be the appropriate immediate action? a. All the actions listed in the other alternatives b. Switch to another generator set se t (that is available) c. Have the failure immediately d. If the failure is in conflict with pre -requisitional electric power supply, ensure manual operation mode until the failure is corrected
110. Which push-button valve A, B or C must be pushed (operated) in order to obtain movement of the pneumatic cylinder S? a. A b. None c. C d. B
111. Which of the logic statements is correct for this pneumatic system? a. S = A or B or C b. S = (A or B) and C c. S = A or (B and C) d. S = A and B and C
112. What do you understand by the expression Master Contro ller? a. The Captain’s controller b. State of the art controller c. The primary controller in a cascade control-system d. The best possible control system 113. What do you understand by the expression Slave Controller? a. The secondary controller in a cascade control system b. Feed water controller c. The controller is following a pre-set control se quence d. The controller is always working hard 114. What is the meaning of “remote mode” related to a slave controller? a. The slave controller receives the se t-point from the output signal of the master controller b. The slave controller can be turned from t he engine control room c. The slave controller can be in any mode of operation d. The slave controller can be tuned by a hand carried remote controller 115. When tuning a cascade control system, where do you start? a. Both at the same time b. The slave controller with the master controller in manual mode c. The slave controller with the master controller in auto mode d. The master controller 116. In a cascade control system, what is the correct mode of the t he slave controller during normal operation? a. The slave controller shall be in remote mode b. The slave controller shall be in auto mode c. The slave controller shall be in manual mode d. The slave controller can be in any mode 117. PT-100 sensors are sometimes used with 3 or even 4 wires. What is the reason for this? a. For fault indication b. Because of power-consumption c. Higher measuring accuracy d. Higher mechanically strength of the cable 118. Temperature sensors may be marked Pt 100 . What does it mean? a. 100 ohm at 0 deg C b. 20 ohm at 100 deg C c. 100 ohm at 20 deg C d. 0 ohm at 100 deg C 119. Temperature sensors may be marked Pt 802 . What does it mean? a. 802 ohm at 20 deg C b. 20 ohm at 802 deg C c. 100 ohm at 20 deg C d. 20 ohm at 100 deg C
120. Which component does this graphical gr aphical symbol illustrate? a. Pressure relief valve b. Flow controller c. Pressure switch d. Pressure-reducing regulator
121. Which component does this graphical gr aphical symbol illustrate? a. Thermocouple b. Resistance temperature sensor c. Triac d. Potentiometer
122. Which component does this graphical gr aphical symbol illustrate? a. Pressure indicator, installed on panel/console b. PH analyser c. Pressure relief valve, self-contained d. Pressure indicator, installed locally
123. Which of the following letter combinations represents a level indicating controller on a process and instrumentation diagram? a. LIC b. LIR c. CIR d. CIL 124. Which of the following letter combinations represents a temperature controller on a process and instrumentation diagram? a. TIC b. FIC c. PIC d. TC 125. Which component does this graphical gr aphical symbol illustrate? a. Remote level controller with indicator b. Level switch for centre-tank c. Low carbon incinerator d. Low level controller with indicator 126. Which component does this graphical gr aphical symbol illustrate? a. Rectifier b. Inverter c. Differential pressure transmitter d. Pressure to electric current converter
127. What is the most common signal from an I/P converter? a. 4-20 mA/3-15 PSI b. 0-20 mA/0-20 PSI c. 0-10 V/3-15 PSI d. 0-1 mA/1-2 BAR 128. What is an I/P transducer? a. A transducer that increase a pressure signal which is too low to give the desired effect b. A transducer that converts a pressure to a proportional electric signal c. A transducer that is inverting a pressure signal d. A transducer that converts a known electric current to a pressure proportional to the current 129. When calibrating a pressure transducer we have to adjust both SPAN and ZERO. Please indicate in which order these adjustments should be done. a. The order of adjustment is no importance b. First Span adjustment and then Zero adjustment. After that Span setting should be checked again c. First Zero adjustment and the Span adjustment. Then Zero should be rechecked d. First Span adjustment and then Zero adjustment. After that Span setting should be checked again.
130. U-tube manometers are often used to measure differential pressure. Which of the listed pressures is U-tube manometers mostly used for? a. Absolute zero pressure b. High differential pressures c. Cargo pressure d. Low differential pressures
131. Which type instrument is shown on this picture? a. Electric Contact manometer b. Vacuum type manometer c. Differential pressure manometer d. Digital manometer
132. The manometer shown on the picture has an accuracy class 1.0. What is the measuring accuracy if the pointer indicates 6.0 bar? a. +/- 0.06 bar b. +/- 1.0 bar c. +/- 0.5 bar d. +/- 0.12 bar
133. The picture shows a liquid filled thermometer. Liquid filled thermometers and manometers are often installed on-board ships. What is the main purpose by the liquid filling of such pointer instruments? a. Avoid water penetration from outside b. Keep the rear side of the front glass clean c. Reduce mechanical wear on the inter nal parts caused by vibration d. Compensating for changes in ambient temperature
134. Which type of temperature sensor is used in this temperature measuring system? a. Thermistor sensor b. Platinum resistance sensor c. Thermocouple sensor d. Quartz sensor
135. Thermocouples are often used for measuring temperatures. Which of the following descriptions are valid for a thermocouple? a. A semi-conductor device that exhibits a negative coe fficient of resistance with temperature b. A resistance device that exhibits a positive coefficient of resistance with temperature c. A quartz crystal that changes its resonant r esonant frequency with temperature d. A junction between two dissimilar metals generates a small voltage
136. Which of the following detectors will you choose for detecting smoke from fire? a. Thermometer b. Thermocouple c. Strain gauge d. Ionization type
137. Some equipment may be marked with the following symbol: What does that mean? a. Explosion proof b. Internally explosion proof c. Not safe in gas dangerous area d. Intrinsically safe
138. What is an A/D and a D/A converter? a. A converter establishing the voltage b. An amplifier for direct current c. A converter that converts alternating current into direct current and vice versa d. A converter that converts an analogue signal to a digital signal and vice versa
139. What is the meaning of term “Span” of transducer? a. Type of standard output signal according to ISO b. The difference between maximum and minimum measurement that gives a standard output signal c. The maximum output signal when you have a minimum process value d. The length between the connecting flanges 140. Which type temperature sensors are shown on this picture? a. Thermistor type NTC b. Resistance sensors c. Thermocouple sensors d. Thermistor type PTC 141. What is the meaning of term “Range” of transducer? a. The difference between possible maximum and minimum measurement b. The length between the connecting flanges c. The maximum output signal when you have a minimum process value d. Type of standard output signal according to ISO 142. Thermistor will typically have a. Relatively nonlinear characteristic b. Variable reliability c. Inaccurate measurement d. Relatively linear characteristic 143. Thermo-elements will typically have a. Medium range of temperature measurement b. Relatively narrow range of temperature measurement c. No influence at all on the readings d. Relatively wide range of temperature measurement 144. When we are measuring temperature with a thermistor, the name of the sensing device is: a. Temp sensitive semi-conductor b. Junction of two dissimilar metalls c. Capacitance probe d. Platinum wire 145. Will it matter to the accuracy of the measurement how you are installing a resistance element in a thermo-well? a. Wrong installation will result in a major deviation in measurement b. Will only result in mechanical problems c. Will have a minor influence d. No influence at all 146. What is the advantage of a transmitter with a narrow measurement range? a. Easy installation b. Better linearity and increased accuracy c. Do not need any calibration d. Lower purchase cost
147. Why is it important that a transmitter has been correctly installed at the correct place? a. The control system is depending on the best possible process signal b. Can be installed anywhere in the piping system c. It is important to have easy access to the transmitter for maintenance d. It must be easy to o bserve for troubleshooting 148. What is the meaning of instrument calibration? a. Comparing two instruments of the same type b. Comparing input and output values against a documented standard c. Turning gauge too an easy reading position d. Adjusting size to fit process connection
149. Two reference points for pressure exist, absolute zero and atmospheric pressure. What do you call pressures measured relative to atmospheric pressure? a. Gauge pressure b. Pressure drop c. Absolute pressure d. Atmospheric pressure
150. You have to choose one of the following instruments for measuring pressure in an air bottle in measuring range 0 35 BAR. Which instrument will you install? a. Bourdon Tube manometer b. U-type Hg manometer c. U-type H20 manometer d. Bellow type manometer 151. Choose the group of electrical power supplies that best fits the identification of “Emergency”. a. Shaft generator and emergency diesel b. Batteries and No. 1 diesel c. No.1 diesel and No. 2 diesel d. Emergency diesel and batteries
152. Choose the group of electrical power supplies that best fits the identification of “Mains”. a. Shaft generator and emergency diesel b. Batteries and No. 1 diesel c. No.1 diesel and No. 2 diesel d. Emergency diesel and batteries 153. It is possible to operate two similar g enerators in parallel at equal power (kW) but at different power factors. The generator with lower power factor will cause it to run: a. Hotter due to increased current b. Faster due to increased voltage c. Cooler due to increased current d. Slower due to increased current
154. Generator 1 and 2 are working in parallel. Prime-mover 2 suffers a total fuel loss. The likely outcome is: a. Generator set 2 trips on reverse speed b. No.2 generator trips on reverse power c. No. 1 machine overloads and trips out on over speed d. No.1 machine over speeds and trips out on overload
155. If the A.C. line current in a generator is doubled, the heating effect in the stator windings will: a. Half b. Double c. Quadruple d. Remain about the same 156. When a blackout occurs: what should be your first r eaction? a. Cancel audible alarms b. Investigate the cause of the blackout c. Inform the bridge about the reason for blackout, and expected time to restart d. Inform the Chief Engineer 157. For two generators running in parallel, t heir share of additional load (kW) will be determined by the: a. Governor droop settings on each prime mover b. The temperature difference between the generator rotors c. The power factor of the additional load d. Voltage droop setting on each AVR 158. When a large motor load suddenly is disconnected from the switchboard and the generator is AVR controlled, the voltage will? a. Remain approximately constant, due to governor action b. Initially fall, then reset to the se t value c. Initially rise, then reset to the set value d. Remain approximately constant, due to AVR action 159. Regular (at least weekly) testing of the emergency generator must be performed to check: a. Its environmental noise factor during emergency fire -drills b. Its readiness to perform as specified c. Its voltage/current characteristics d. Its compliance with the shipbuilder’s recommendations
160. An electrical power emergency source in a ship is required because: a. The main diesel generator(s) can be taken out of service for overhaul or repair b. The ship’s total load can be shared between bet ween main and emergency generators c. It satisfies the SOLAS requirements for ship safety d. It satisfies the need to be environmentally “friendly”
161. Check-synchroniser is often installed to: a. Allow auto-synchronising to take place b. Prevent manual synchronising outside permitted limits c. Ensure fair equal sharing between generators d. Permit faster paralleling
162. The correct time to synchronise is usually taken to be when the Synchroscope reaches the “5 to 12” 12” position. This allow for: a. Generator phase difference error b. Circuit breaker operating time c. Synchroscope error d. Synchroscope pointer time lag
163. Under normal conditions, the electric power for services supplied from the emergency switchboard is supplied from: a. Emergency batteries b. The main diesel generator or shaft generator c. A compressed air driven generator d. An emergency battery charger 164. After main power is restored, a timed sequential restart of motor-driven auxiliaries is necessary to avoid: a. Overvoltage due to current surges b. Over-frequency due to overspeed of generator c. Generator overload due to many motors starting at simultaneously d. Overloading creating earth faults 165. The pair of instruments necessary for generator synchronising are: a. Voltmeter and Synchroscope b. Synchroscope and kVar-meter c. kW meter and frequency meter d. Amp-meter and Volt-meter 166. During synchronising, the incoming generator should be running slightly “fast” compared to the busbar frequency. This is to ensure that the: a. Incomer picks up as a motor b. Incomer picks up as a generator c. Incomers reverse power trip is tested d. Most rapid synchronising action is achieved 167. For ideal synchronising, the phase angle difference between the incomer e.m.f. and the busbar voltage should be: a. 0 deg b. 30 deg behind c. 30 deg ahead d. 90 deg lag
168. Unloading a generator, it is neces sary to gradually decrease the load in order to avoid: a. Undue overspeeding b. Undue temperature rise c. Undue overcurrent d. Undue overload on the switchboard
169. Prior to synchronising, the generator voltage and fre quency are respectively controlled by: a. Voltmeter and frequency meter b. AVR and speed governor c. Synchroscope and speed governor d. Speed governor and load power factor 170. After successful synchronising the kW and kVar loading are respectively transferred by the following controls: a. Voltage regulator and Synchroscope b. Speed governor and voltage regulator c. Speed governor and load power factor d. Current regulator and voltage regulator 171. Which group of electrical services are likely to be supplied from an emergency generator? a. Sound powered telephone system b. Engine room lighting and bow thruster c. Galley and air conditioning d. Steering gear and alarm system 172. Please indicate the correct sequence of action to take place in an alarm/monitoring and safety system. a. Alarm, st. by start, slowdown, shutdown b. At. by start, alarm , slowdown, shutdown c. Alarm, slowdown, st. by start, shutdown d. Alarm, slow down, st. by start, shutdown
173.
What is the symbol for a THYRISTOR? a. Figure 1 b. Figure 2 c. Figure 3 d. Figure 4
174. Which alternative is correct for measuring current over the load L? a. Figure 3 b. Figure 2 c. Figure 1 d. Figure 4
175. The function of the fuses in a motor starter circuit is to provide: a. Overload protection b. Under voltage protection c. Short circuit protection d. Open circuit protection
176. A motor is protected by a thermal overcurrent relay. After tr ipping on overload it will not be possible to reset the overcurrent relay because the: a. Line contactor spring also has to be reset b. Oil dash-pot has also to be reset c. Starter isolator automatically applies an interlock d. Bimetallic strips need time to cool down 177. “Protective discrimination” means the progressive grading of sizes/tripping times of: a. Generators and motors b. Line fuses and over current relays c. Magnetic and thermal current transformers d. 440 V and 220 V transformers
178. When 3 phase alternators are operating in parallel, it is very important that t he reactive load is evenly shared so that the total alternator loads are evenly shared. If the total alternator load is t he vector sum of active and reactive loads, which side of the vector diagram shown represents the reactive load? a. (Y) b. Either (X) or (Y) c. None of the mentioned alternatives d. (X)
179. The insulation resistance (IR) to earth of a new galley hot-plate is measured to be 30Mohm. When three identical hot-plates are te sted together their combined IR will be: a. 30 Mohm b. 90 Mohm c. 3 Mohm d. 10 Mohm
180. When data are to be transferred over telephone lines, we often utilize modem at each end. Which of the following adapter cards (parts) will you use for interfacing a modem to a computer? a. Enhanced graphic adapter b. VGA display adapter c. Parallel adapter d. Serial adapter
181. The power supply to the hard disk of a personal computer consists normally of two voltages. Which? a. 5 V and 12 V b. 1.5 V and 5 V c. 12 V and 48 V d. 12 V and 24 V 182. Where in the personal computer is the BIOS system located? a. On the motherboard b. On the keyboard c. On the hard disk d. On the Video Adapter Card 183. What do you understand with a computer’s POST system? a. An old type video adapter b. A series of tests run by the computer at power on c. An area of the hard disk that stores the DOS system d. Storage area in memory having a specified storage capacity
184. Which electronic component is this graphical symbol illustrating? a. Resistance, 3300 ohms b. Electric heater, 3.3 kW c. Inductive reactor, 3.3 kH d. Capacitor, 3.3 F 185. Which electronic component is this graphical symbol illustrating? a. Auto transformer b. Variable inductive reactor c. Variable electrical heater, 10 kW d. Potentiometer, 10 kohm 186. Temperature sensors of all types are normally mounted in a well, or pocket, when used in pipelines. Why? a. Avoid electric current flowing from the se nsor to the liquid b. Decrease the temperature gradient between the liquid and the sensor c. Allow removal of the sensor also when liquid is flowing in the pipe d. Suppress electro-magnetic interference between liquid in the pipe and the sensor
187. Which of the following temperature sensors does normally give the highest measuring accuracy? a. Resistance sensor, Pt100 b. Thermistor, NTC c. Thermocouple, NiCrNi d. Thermistor, PTC
188. Use Kirchhoff’s voltage law and Ohm’s law to c alculate the voltage V(2) across the resistance R(2). a. 4.5 V b. 6 V c. 0.75 V d. 2 V 189. In a fresh water tank with a height of 5 meters we shall use a pressure transmitter for level measurement. The tank has a vent-pipe leading to deck 8 meters above the top of the tank. What pressure shall we use as a guidance when ordering the pressure transducer? a. 0.5 Bar b. 0.8 Bar c. 2.0 Bar d. 1.3 Bar
190. In a fresh water tank we are using a pressure transmitter with a range of 0-0.5 bar/ 4-20 mA for level measurement. The transmitter is for different reasons installed 30 centimetres from the bottom of the tank, and the tank is 5 meters high. What will the output from the t ransmitter be when the tank is full? (Pending no calibration is made) a. 18.8 mA b. 30 mA c. 20 mA d. 21.2 mA
191. In a fresh water tank we are using a pressure transmitter with a range of 0-0.5 bar/ 4-20 mA for level measurement. The transmitter is for different reasons installed 30 c entimetres from the bottom of the tank, and the tank is 5 meters high. What will the output from the transmitter be when the tank is empty? a. 5.2 mA b. 2.8 mA c. 2 mA d. 4 mA 192. In what kind of measuring equipment can we find a Bourdon-tube? a. In a temperature transmitter b. In a pressure transmitter c. In an A/D converter d. In a flow meter
193. Which of the following detectors will you use for detecting if a watert ight steel door is closed or open? a. Proximity switch b. Transducer c. Synchro d. Strain gauge
194. Which of the following instruments is normally part of a control -loop? a. Transducer b. Gauge c. Indicator d. Plotter
195. Which of the listed physical parameters can be measured by means of a manometer? a. Temperature b. Strain c. Pressure d. Motion 196. Which of the listed sensors cannot be utilized for detecting temperatures? a. Strain gauge b. Pt 500 c. Thermocouple d. Thermistor 197. How do you express the accuracy of an instrument? a. In % of range b. In % of gauge readings c. In % of deviation d. In % of full scale
198. One or a certain number of smoke sensors are switched off during routine maintenance work to preve nt false alarm. During coffee break the following precautions are taken: a. Switching to UMS-mode, leaving alarms unengaged b. Switching to UMS-mode, UMS-mode, leaving one of the ratings “on wat ch” c. Leaving one of the ratings “on watch” d. All alarms are reengaged prior to switching to UMS-mode
199. A 3-phase induction motor is rated at 200 A. Its initial direct-on-line starting current will be approximately: a. 1000 A b. 500 A c. 100 A d. 5000 A
200. A 3-phase A.C. induction motor is running normally at its rated curre nt of 150 A when a single phasing fault (open circuit) occurs in one line. The likely outcome will be: a. Line currents: 75 A, 75 A, 75 A. Trip c ondition: no trip but speed falls b. Line currents: 0 A, 180 A, 180 A. Trip condition: trip on overload c. Line currents: 150 A, 150 A, 150 A. Trip condition: fuses blow on short circuit d. Line currents: 0 A, 150 A, 300 A. Trip condition: trip on overload
201. An earth fault exists on the blue line of a 100 A bilge pump circuit. A second earth fault occurs on the yellow line of a 10 A ventilation fan circuit. The likely outcome is t hat: a. A short circuit occurs between earth fault and the bilge pump fuse blows b. Both motors trip out on overload c. An open circuit occurs between e arth fault and both motors trip out d. A short circuit occurs between earth faults and the ventilation fan fuse blows
202. The internal e.m.f. generated in the phase windings of an a.c. generator is controlled by: a. The diesel speed and load current b. The diesel speed and excitation current c. The internal volt drop and the residual magnetism d. The internal volt drop and the load current 203. A 10% reduction in generator speed occurs due to a faulty governor. The likely consequence for each motor powered from this generator is to: a. Increase motor speed by about 10% b. Reduce motor volt drop by about 10% c. Increase motor power by about 10% d. Reduce motor speed by about 10% 204. The figures show a graphical symbol for a particular e lectronic component and a typical working characteristic for the same. Which component? a. Zener diode b. Thyristor c. Tunnel diode d. Transistor
205. Which electronic component is this graphical symbol illustrating? a. Transistor b. Tunnel diode c. Diode d. Silicon controlled rectifier
206. This amplifier circuit is a very common configuration used to amplify the difference in voltage between two input signals; in this case input 1 and 2. What is this amplifier called? a. Differential amplifier b. Common emitter amplifier c. Push-pull amplifier d. Darlington connection amplifier
207. Radio frequency signals can carry information from one place to another if it is modulated. There are several ways to modulate a carrier. Which modulating method is illustrated here? a. Amplitude modulation (AM) b. Pulse Width Modulation (PWM) c. Pulse Code Modulation (PCM) d. Frequency Modulation (FM)
208. The circuit symbol is a driver for a solenoid (coil) of a solenoid valve S. What is the purpose of the diode 1N4002 connected in parallel to the solenoid S? a. Blocking inductive kick from the solenoid b. Open for current flow between the operational amplifier and the transistor 2N5194 c. Blocking for +15V to the emitter of the transistor 2N5194 d. Making voltage drop of approximate 0.5V between the operational amplifier and the transistor 2N5194
209. The thermal expansion valve responds to the a. Amount of superheat in the vapour leaving the coil b. Pressure in the evaporator coil c. Temperature in the evaporator coil d. Amount of superheat in the vapor in the liquid
210. In a circuit diagram of a simple hydraulic circuit, what does the following symbol indicate? a. Double check valve b. Directional control valve c. Throttle valve d. Pressure relief valve 211. In connection with exhausts gas measurement with a thermocouple we are normally an amplifier which gives a mA-signal out. Why is this done? a. The signal out from a thermocouple is mV, and cannot be transferred over any longer distance without loss of voltage, giving a very bad accuracy b. This depends on the length of the compensation-cable c. The signal out from the thermocouple is also mA, but have to be amplified in order to give a good signal to the alarm system d. To stabilize the signal 212. What is the signal we measure from a NiCr/Ni thermocouple? a. mV b. Watt c. Ohm d. mA
213. P= U x I x Root of 3 x cos (f i). What is the formula for I? a. Formula 1 b. Formula 2 c. Formula 3 d. Formula 4 214. Find the value of the voltage drop from terminal A to terminal B in this circuit? a. -38 V b. +24 V c. +19 V d. -48 V
215. What is this? a. A measuring bridge b. An amplifier c. A Zener barrier. (Positive) d. A rectifier
216. These circuits are all active filters. Which of the circuits is a Bandpass filter? a. Figure 2 b. Figure 3 c. Figure 4 d. Figure 1 217. These circuits are all active filters. Which of the circuits is a Low pass filter? a. Figure 4 b. Figure 3 c. Figure 2 d. Figure 1 218. These circuits are all active filter s. Which of the circuits is a High pass filter? a. Figure 2 b. Figure 4 c. Figure 3 d. Figure 1
219. Which of the 4 alternatives shows a NPN transistor? a. Figure 2 b. Figure 3 c. Figure 4 d. Figure 1
220. Which of the 4 alternatives shows a PNP transistor? a. Figure 2 b. Figure 3 c. Figure 4 d. Figure 1
221. Earthing of signal cables. Which of the 4 alte rnatives is correct for a cable of analogue signals? a. Figure 1 b. Figure 2 c. Figure 3 d. Figure 4
222. This is an electronic temperature controller. You have been asked to adjust the controllers integrating action. Which button on the front of t he controller shall be utilized for this adjustment? a. Pos. 2 b. Pos. 7 c. Pos. 6 d. Pos. 8
223. The pressure inlet to a pressure gauge is varied from zero to full scale and back to zero again. The output (indicating pressure) versus true pressure is shown in the diagram. The non-coincidence of loading and unloading curve is due to internal friction in the instrument. What do w e call this phenomenon? a. Dead band b. Resolution c. Hysteresis d. Threshold
224. What is Hz the abbreviation for? a. Frequency in an Alternating Current (AC) b. Measure for Resistance c. Revolution per minute d. Frequency in Direct Current (DC)
225. A ships 3-phase a.c. circuit has 440 V and 220 V transformer linked sections. The effec t of a single earth fault on a 220 V line will cause the t he following earth lamp indication: a. In 440 section: All lamps equally bright. In 220 section: All lamps dark b. In 440 V section: One lamp dim. In 220 V section: One lamp dim c. In 440 V section: Two lamps bright. In 220 V section: Two lamps bright d. In 440 V section: sect ion: All lamps equally bright. In 220 V section: One lamp dim 226. The earth lamps in a 3-phase system indicate as follows: Red=bright Yellow=dark Blue dim a. Light earth – earth – hard hard earth – earth – no no fault b. Light earth – earth – no no fault – fault – hard hard earth c. no fault – fault – hard hard earth – earth – Light Light earth d. hard earth – earth – light light earth – earth – no no fault 227. Transmission lines play a central role in radio frequency circ uits, where they are used to pipe signals around from one place to another within a circuit, and often to an antenna system. General rules for s uch transmission line is that they must be “matched”. Which of the cables below would you use to use to obtain a matched transmission between Z1 and Z2? a. Figure 2 b. Figure 3 c. Figure 4 d. Figure 1
228. There are many applications in circuit theory wher e it is important to obtain the maximum possible power that a given source can deliver. This figure consists of a practical voltage source V(g) with internal resistance R(s). A resistance R(L) will maximize the power transmission from the source to R(L)? a. R(L) = 0.5 R(s) b. R(L) = 2 R(s) c. R(L) = R(s) d. R(L) = R(s)/sqrt(3)
229. Which of the following detectors will you choose for detecting torque of a steel shaft? a. Synchro b. Strain gauge c. Ultrasonic gauges d. Pyrometer
230. What is meant by being intrinsically safe? a. Product having a special writing system b. Electric wiring executed by approved manufacture c. Cannot produce enough energy to ignite a gas (explode) d. Any electrical product, being water re sistant
231. What is the difference between a THERMOSTAT and a TEMPERATURE TRANSMITTER, if any? a. The thermostat gives out an analogue signal depending on the switch setting. The temperature transmitter gives out a binary signal depending on t he temperature b. There is no difference c. The temperature transmitter is a digital component while the thermostat is an analogue component d. The thermostat has one or more contacts (open or closed) depending on the temperature/setting. The temperature transmitter converts a temperature signal to an electric signal. 232. What is the difference between a PRESSURE SWITCH and a PRESSURE TRANSMITTER, if any? a. There is no difference b. The pressure switch has contact(s) that will change between open and closed position. The pressure transmitter convers a pressure signal into an e lectric signal c. The pressure switch gives out a digital signal dependent on pressure and temperature. The pressure transmitter converts a pressure signal to a digital signal d. The pressure switch gives out an analogue signal depending on the switch setting. The pressure transmitter gives out a binary signal depending on the pre ssure 233. When the cable length from the temperature sensor to the place where we want to read the temperature exceeds approx. 10 meters we normally have to, in case of a Pt 100, in some way to compensate for the cable resistance. Do we also have to do this if we choose to use a T802 temperature? a. Not applicable b. No c. Yes d. Depends on temperature to be measured 234. Choose the resistance R from the list A to D which allows highest possible current without exceeding 5W power consumption. a. R(S) = 50 ohm b. R(S) = 30 ohm c. R(S) = 10 ohm d. R(S) = 25 ohm 235. Ordinary thyristors (SCR) must often be protected against reverse overvoltage transients because even over-voltages of extremely short duration can destroy them. These circuits have been given such over-voltage protection, but only one of them is correct. Which? a. Figure 1 b. Figure 4 c. Figure 3 d. Figure 2 236. What is the purpose of the Oil Mist Detector? a. To detect the circulating oil b. To avoid suffering box leakages c. To detect oil mist ( explosive atmosphere in the crankcase) d. To avoid hot spots in crankcase
237. In the diagram below we want to verify the resistance of the PT 100 sensor. What is the correct calculation? a. R(Pt100) = R1 - R2 b. R(Pt100) = R1 x R2 c. R(Pt100) = R1 : R2 d. R(Pt100) = R1 + R2
238. This block diagram illustrates an elementary control system. What do we call such system in general? a. Open loop feedback system b. Feed forward system c. Schmitt trigger d. Closed loop feedback system
239. Due to the relatively low resistance of a Pt100 sensor we might have to compensate for the cable-resistance to ensure a correct reading. Which of the 4 alternatives given is correct for the connection of this compensation resistance? a. Figure 2 b. Figure 4 c. Figure 3 d. Figure 1
240. The diagram is a calibration diagram for a pressure gauge. What do you call the slope of the calibration curve? a. Repeatability b. Off-set c. Hysteresis d. Sensitivity
241. An important quantity which is useful in circuit analysis is known as conductance G (Siemens). Which of the formulas A to D e xpresses the conductance for this circuit? a. 2 R b. R * I c. 1/R d. I/R
242. Liquid level in tanks is often measured by measuring the hydrostatic head o r differential pressure. One method is the air bubble type which is illustrated here. Calculate the level in tank, utilizing the figures given on the drawing. a. 500 cm b. 640 cm c. 200 cm d. 320 cm
243. What is a ZENER BARRIER? a. A Zener barrier is a diode bridge used in rectifiers b. A Zener barrier is a device used for speed regulation on electric motors c. A Zener barrier is a device that allows the current to pass only one direction d. A Zener barrier is a unit made to obtain intrinsically safety in installation for instrumentation in hazardous areas. 244. Can a ZENER BARRIER be installed in hazardous area? a. Yes, that’s what the Zener barrier is made for. b. Only if properly marked for such installation c. Only in equipment operating on very low voltage d. No, as only the output from the barrie r is intrinsically safe this is not allowed 245. This circuit is a transformer with two windings, N(1) = 2000 and N(2) = 1000 turns, on a common magnetic circuit. Assume that there are no energy losses in the transformer itself. Calculate t he output voltage V(2) when the input voltage is V(1) = 100 Volt. a. 200 V b. 50 V c. 400 V d. 10 V
246. This is a typical emitter follower. What is the main benefit obtained by use of an emitter follower? a. The input impedance is made much larger than the output impedance b. The input impedance is made much smaller that the output impedance c. The collector can be connected to as high-voltage as 10V DC d. The V out is always equivalent to the V in
247. This is a simplified block diagram of a dc ge nerator and its voltage regulator. Find the value of the feedback co nstant H if the reference VR is a 45-Volt battery and the terminal voltage Vt is to be 250 Volt. a. 0.55 b. -0.178 c. -11.1 d. 5.5 248. Which method is best for determining e arth failure on a 24VDC power supply? a. A megger-tester b. A lamp, (0-50 mA) and a mA-meter in series c. An mA-meter d. A digital V-meter
