Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Description : When troubleshooting a console circuit card which is suspected of being faulty, the first step would be to _____. A. pull the card and measure the value of all resistors B. check for the ... for burned components D. check for continuity of circuit board traces and then the gain of each transistor
Last Answer : Answer: C
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Normally, the FIRST step in troubleshooting a transistor circuit card is to _____________. A. carefully remove the transistors from the card B. give the circuit an initial test with a signal generator C. test for continuity with a low voltage DC supply D. visually inspect the card
Last Answer : Answer: D
Description : When troubleshooting a console circuit card suspected of being faulty, first check for proper voltages to the card and then _______________. A. test transistors or integrated circuits for gain and ... D. de-energize the card and check the printed circuit traces for continuity with an ohmmeter
Description : The ring circuit of the system shown in the illustration would become inoperative if a ground developed at ____________. EL-0093 A. either terminal 'T' or 'C' B. either terminal 'B' or 'R' C. both terminals 'B' and 'C' D. both terminals 'T' and 'R'
Description : The 'T-R' circuit of the system shown in the illustration would become inoperative if a ground developed at ____________. EL-0093 A. either 'T' or 'C' B. either 'B' or 'R' C. both 'B' and 'C' D. both 'T' and 'R'
Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections
Last Answer : Answer: B
Description : Erratic operation of the devices represented in the diagrams shown in the illustration could be traced to ____________. EL-0092 A. improper contact at 'R' slip rings or 'S' connections B. a low three- ... . improper contact at 'S' slip rings or 'R' connections D. a high three-phase voltage supply
Last Answer : Answer: A
Last Answer : Req= (1/1200 +1/560 + 1/2.1)^-1 = 2.1 ohms RT= 2.1 + 7.8 = 9.9 ohms IT = V/R = 24/9.9 = 2.4 A Veq= R I = 2.1 2 ... 7.8 = 12.096 w = 44.928 w _________________________________________ By: Ellis-Junior Kamatjipose [email protected]
Description : A series wound DC motor has its armature and field connected in series with a resistor. When the motor is disconnected from its power supply, this motor will exemplify __________. A. the ... the proper connections for an automatic strip heater C. a reversing controller circuit D. dynamic braking
Description : One of the following is a possible cause for a slow drift of frequency in a self-exited transmitter oscillator circuits resulting to a poor frequency stability. A. Loose shielding B. ... capacitor in the oscillator C. Poor soldered connections D. Faulty capacitor, resistor, tubes or resistors
Last Answer : B. Heating of capacitor in the oscillator
Description : If coils 'R1-R2-R3' at the receiver of figure 'B' shown in the illustration turned opposite of those in the transmitter by design, what corrective action should be taken? EL-0092 A. Reverse the 60 Hz supply ... is needed. C. Interchange leads 'R1' and 'R3'. D. Interchange leads 'R2' and 'R3'.
Description : If coil 'R1-R2' at the receiver of figure 'A' shown in the illustration were in 180 degree error with respect to that of the transmitter, what corrective action should be taken? EL-0092 A. No action is ... and 'R2'. C. Interchange connections 'S1' and 'S2'. D. Interchange connections 'S1' and 'S3'.
Description : If coils 'R1-R2-R3' at the receiver of figure 'B' shown in the illustration turned opposite of those in the transmitter, what corrective action should be taken to have both turn in the same direction? EL-0092 A ... is needed. C. Interchange leads 'R1' and 'R3'. D. Interchange leads 'R2' and 'R3'.
Description : If coil 'R1-R2' at the receiver of figure 'A' shown in the illustration turned opposite of that in the transmitter, what corrective action should be taken? EL-0092 A. No action is necessary as this is ... . C. Interchange connections to 'S1' and 'S2'. D. Interchange connections to 'S1' and 'S3'.
Description : The current from the stator of an alternator is taken out to the external load circuit through (A) slip rings. (B) commutator segments. (C) solid connections. (D) carbon brushes.
Last Answer : (C) solid connections.
Description : When troubleshooting electronic equipment, the FIRST step to be taken before testing the circuit voltage is to _________. A. set the meter to the lowest range B. check the voltage supply from the power source C. remove the suspected component D. check the current flow through the circuit
Description : During start-up of the circuit shown in the illustration, it is noted that the ends of component 'C' alternately glow and become dark without the tube illuminating. The most probable cause ... start the lamp D. component 'B' contacts are opening and closing thus prohibiting sufficient current flow
Description : When troubleshooting a console circuit card suspected of being faulty, the last step would be to _______________. A. check the fuses and voltage levels of all power supplies in the console B. clean dust ... -on types D. substitute a new or repaired spare card and check the operation of the circuit
Description : When a solid-state component of an electronic circuit is mounted to a metallic mass, the general purpose of that mass is to ____________. A. prevent vibration damage to delicate components B. prevent ... damage to solid-state components C. dissipate stray magnetic currents D. act as a heat sink
Description : When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, you must ____________. A. insulate the field frame from the ship's hull B. disconnect each shunt ... C. use a motor driven high capacity megohmmeter D. remove all main line lead connections before testing
Description : When an AC or a DC motor fails to start, the FIRST step in troubleshooting should be to check the ____________. A. motor windings for obvious opens B. motor controller leads for continuity C. fuse or circuit breaker D. motor controller leads for grounds
Description : You are reconnecting a three-phase induction motor to the supply line. To prevent possible damage to the load, due to the wrong direction of rotation, you should ____________. ... supply line phase sequence and motor rotation with appropriate indicators, then connect correspondingly marked leads
Description : Which type of flux should be used when soldering electrical wire connections and electronic components? A. Silver flux B. Rosin flux C. Solid flux D. Acid flux
Description : A transformer in an electric circuit serves to ____________. A. generate its own electrical power B. transform electrical energy into mechanical energy C. increase or decrease circuit voltage as required D. convert AC current to DC current
Description : In a DC series circuit, all the conductors have the same ____________. A. power expended in them B. voltage drop across them C. resistance to current flow D. current passing through them
Description : One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° ... C. line current equal to the phase current D. line voltage equal to the phase voltage
Description : Voltage generated by most AC generators is fed from the machine to the bus by means of ____________. A. brushes on a commutator B. brushes on slip rings C. slip rings on a commutator D. direct connections from the stator
Description : Peripheral components for the operation of the astern valve position amplifier circuit shown in the illustration are _____________. EL-0099 A. resistors B. operated on +28 volts D.C. C. located on a separate circuit card D. all of the above
Description : When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only ... being tested D. so as not to load down the circuit and obtain erroneous voltage readings
Description : While troubleshooting a circuit in an engine room central control console, a resistor is suspected of being faulty. Which of the following precautions must be observed if an ohmmeter is to be used to ... of the component isolated. D. The meter case must be grounded prior to attaching the leads.
Description : After turning on the fluorescent lamp shown in the illustration, you note that the ends of the tube alternately glow and becomce dark without illuminating the center. The most obable cause for ... the lamp D. component 'B' contacts are opening and closing thus prohibiting sufficient current flow
Description : The illustration shows a fluorescent light fixture. The ends of the lamp alternately glow and become dark, but the tube will not light. The most probable cause is that ____________. EL-0081 ... start the lamp D. component 'B' contacts are opening and closing thus prohibiting sufficient current flow
Description : When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors ... circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit
Description : Which of the listed conditions could cause a DC motor to have excessively hot windings and sparking at the brushes? A. Reversed interpole polarity B. High bar-to-bar voltage C. Loose brushes D. Excessive humidity
Description : If coils 'R1-R2-R3' at the receiver of figure 'B' shown in the illustration were in 180 degree error with those of the transmitter, what corrective action should be taken? EL-0092 A. Reverse the 60 Hz ... is proper operation. C. Interchange leads 'R1' and 'R3'. D. Interchange leads 'R2' and 'R3'.
Description : Which of the following precautions should be taken when troubleshooting various power circuits using a common solenoid-type mechanical voltage tester (wiggins)? A. Never use this tester on circuits greater ... voltage expected in the circuit in order to prevent damage from an off-scale reading.
Description : A battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? A. 2 volts B. 6 volts C. 12 volts D. 24 volt
Description : The total voltage of a series circuit is the _____________. A. sum of the individual voltage drops B. total resistance divided by the total current C. sum of the individual currents multiplied by the number of resistors D. total current divided by the total resistance
Description : Periodic testing by a shoreside support technician using a special camera which can detect potentially dangerous loose or corroded bus bar and controller connections is termed ______________. A. heat sensitive thermography B. visual pyrotronics C. corrosion electrolysis D. electric vibroanalysis
Description : Excessive heat in an operating motor controller can result from _____________. A. a closed starter contact B. loose connections C. missing arc chutes D. low motor starting torque
Description : The purpose of a heat sink, as frequently used with transistors, is to ____________. A. prevent excessive temperature rise B. compensate for excessive doping C. increase the reverse current D. decrease the forward current
Description : An important characteristic of the device shown in figure 'B' of the illustration as compared with conventional NPN or PNP transistors is its ____________. EL-0065 A. higher temperature sensitivity B. higher power ratings C. very high input resistance D. all of the above
Description : If you reverse both the field and the armature connections to a DC propulsion motor, _____________. A. the direction of motor rotation will change B. the brushes will become overheated C. a magnetic lock will occur in the motor D. the direction of motor rotation will remain the same
Description : Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The ... disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.
Description : In testing a three-phase delta winding for an open circuit using a megohmmeter, you must ______________. A. test each phase with all connections intact B. measure the voltage across the open ... groups to avoid short circuiting D. open the delta-connections to avoid shunting the phase being tested
Description : A complete electronic circuit with transistors and other electronic components on a small silicon chip is called a(n) a) workstation b) CPU c) magnetic disk d) integrated circuit e) None of these
Last Answer : d) integrated circuit
Description : Moisture accumulating in electric motors and generator windings having a cold insulation resistance greater than 50,000 ohms may be baked out with internal heat. This heat can be developed by ____________. ... an electric welder and feeding it into the armature while running the motor at full speed
Description : The voltage developed by an AC generator is controlled by varying the ____________. A. speed of the prime mover B. AC excitation to the field C. DC excitation to the field D. DC excitation of the voltage regulator