Description : Electrical circuits are protected against overheating by means of a/an ______________. A. circuit breaker B. amplifier C. diode D. capacitor
Last Answer : Answer: A
Description : A molded-case circuit breaker provides protection against short circuits by using a/an ________________. A. electromagnet B. shading coil C. arc quencher D. burn away strip
Description : In addition to short circuits and sustained overloads, fuses are likely to blow due to _____________. A. loose fuse clips B. low ambient temperatures C. low contact resistance D. all of the above
Description : A molded-case breaker provides protection against short circuits by using a/an ____________. A. shading coil B. arc quencher C. electromagnet D. holding coil
Last Answer : Answer: C
Description : To provide its unique characteristics to analog circuits, the operational amplifier is made up of a/an ______________. A. voltage amp, current amp and output amp B. input amp, power amp and output amp C. scaling amp, power amp and voltage amp D. differential amp, voltage amp and output amp
Last Answer : Answer: D
Description : Time delayed or delayed action-type fuses are designed to _____________. A. prevent grounds in branch circuits B. prevent opens in motor circuits C. permit momentary overloads without melting D. guard lighting and electronic circuits
Description : Protection against sustained overloads occurring in molded-case circuit breakers is provided by a/an __________. A. overvoltage release B. thermal acting trip C. thermal overload relay D. current overload relay
Last Answer : Answer: B
Description : In addition to testing the calibration of a circuit breaker, maintenance should include all of the following EXCEPT ______________. A. changing out of magnetic elements and thermal heaters yearly B. ... for loose or missing parts D. making sure foreign matter does not block tripping element
Description : An operational amplifier, as used in today's consoles, may have a calculated gain of 5. This means that as the input changes by ______________. A. 1 volt, the output changes 5 volts B. 5 volts, the output changes 1 volt C. 5 volts, the output changes 10 volts D. 10 volts, the output changes 5 volts
Description : The voltage at the reference electrode of the circuit shown in the illustration is applied to the input of a/an ______________. EL-0090 A. class A detector whose output drives an ... drives an 2-stage isolation transformer D. magnetic amplifier whose output controls a saturable reactor
Description : When working on electrical circuits containing large capacitors, in addition to deenergizing the circuit, which of the listed precautions should also be taken? A. Keep all radio equipment ... capacitor insulation resistance. C. Ground the capacitor terminals. D. Check capacitor circuit polarity.
Description : Device used to store energy in electrical circuits is A. resistor B. inductor C. capacitor D. diode
Last Answer : capacitor
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 : In the illustrated circuit, one advantage of the capacitor coupling over direct coupling is ____________. EL-0048 A. as the frequency decreased the capacitive reactance (Xc) increases B. the amplifier becomes ... of the signal while it isolates the biasing of each stage. D. good frequency response.
Description : In the illustrated circuit, the amplifier is connected in what basic configuration? EL-0045 A. common emitter B. common collector C. darlington paired, capacitor coupled D. common base
Description : Where a thermal-acting breaker is required to be used in an area of unusually high, low, or constantly fluctuating temperatures, an ambient compensating element must be used. This element consists of ... arm B. conical spring on the contact arm C. second bimetal element D. second electromagnet
Description : For practical purposes, in a simple series circuit, the source voltage will be dropped across one resistor if it has ______________. A. half the resistance of the other resistor B. a resistance equal to the other C. at least ten times the resistance of the other D. a partial short circuit
Description : In a simple series circuit, the entire source voltage will drop across ______________. A. the resistor next to the negative terminal B. a short circuit C. the resistor next to the positive terminal D. an open circuit
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 : The synchronous reactance of the synchronous machine is ______________. (A) Ratio between open circuit voltage and short circuit current at constant field current (B) Ratio between short circuit ... (D) Ratio between short circuit voltage and open circuit current at different field current
Last Answer : Ans. A The Synchronous reactance of a synchronous machine is a total steady state reactance, presented to applied voltage, when rotor is running synchronously without excitation. Therefore , XS = Ef / IS = Emf of OC for same If / short circuit current
Description : In electronic circuitry, the abbreviation 'PCB' commonly means ______________. A. pulse coded binary B. printed circuit board C. poly-coated braid D. personal computer bits
Description : When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately, or the resultant flashing may _____________. A. blow the lamp's circuit breaker B. explode, ... fly in all directions C. short circuit the ballast transformer D. damage the starter and the ballast
Description : The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an ... an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents
Description : Fuses placed in series with a thermal trip-type circuit breaker are used for _____________. A. time-delay protection B. short-circuit protection C. short duration surge protection D. sustained overload protection
Description : Figure 'A' of the diagram shown in the illustration represents a ______________. EL-0092 A. differential transformer B. saturable reactor C. synchro system D. magnetic amplifier
Description : If an electric motor fails to start, you should FIRST check the _____________. A. phase sequence B. ampere load C. fuse or circuit breaker D. line frequency
Description : Before working on an electric cargo winch master switch or controller, you should _____________. A. spray the gasket surface with a solvent B. drain condensate from the box C. open the circuit breaker in the power supply and tag D. heat the switch box to remove any moisture
Description : The purpose of a short circuit forcing module (short time trip) installed in a branch line is to provide ____________. A. high speed clearance of low impedance short circuits in the branch B. ... C. isolation of short circuits by selective tripping of branch circuit breakers D. all of the above
Description : Capacitors are used on the output of the power supply in today's consoles to _____________. A. filter out 'ripple' B. prevent overloads C. act as a permanent load D. decrease the average value of the output voltage
Description : Keeping in view the cost and overall effectiveness, the following circuit breaker is best suited for capacitor bank switching. A) Vacuum B) Air blast C) SF6 D) Oil
Last Answer : Keeping in view the cost and overall effectiveness, the following circuit breaker is best suited for capacitor bank switching. A) Vacuum B) Air blast C) SF6 D) Oil
Description : A delayed-action fuse is most frequently used in which of the listed circuits? A. Lighting circuit B. Motor circuit C. Electric heater circuit D. Radar circuit
Description : Foldback current limiting has the advantage of A) Better pass transistor protection for long term overloads B) A defined turn on point C) Circuit simplicity D) All of the above.
Last Answer : A) Better pass transistor protection for long term overloads
Description : Which of the device is employed in substation to limit the short circuit current in the power system: a) Shunt condenser b) Reactor c) Series capacitor d) Shunt capacitor
Last Answer : Ans: B
Description : Before touching a small capacitor connected to a de-energized circuit, or even one that is completely disconnected, you should ____________. A. gently tap the body with a screwdriver B. tag it ... insulated fuse puller D. short circuit the terminals to make sure that the capacitor is discharged
Description : What is the relative length of the time constant for the diode capacitor combination in a damper (long or short)?
Last Answer : Short time constant.
Description : In the illustration, the diode between terminals 16 and 17 is to _________. EL-0046 A. act as a short circuit for the sensing coil when CEMF is applied B. insure that the voltage across the coil does not exceed 9 volts C. improve response time D. act as a filter to prevent hunting
Description : The schematic diagram shown in the illustration represents which of the listed solid-state circuits? EL-0069 A. Bridge rectifier B. Magnetic amplifier C. Flip-flop generator D. Cathodic amplifier
Description : RC time constant characteristics, as shown in the illustration, are important in _____________. EL-0086 A. bridge rectifiers for alternator excitation B. timing and pulse shaping circuits C. transistor power amplifier biasing D. motor controller overload protection
Description : Name the two series circuits that exist in a diode circuit.
Last Answer : Filament and plate.
Description : Which of the devices listed is indicated by the electronic symbol lettered as 'A', shown in the illustration? EL-0016 A. Thyristor B. Diode C. Capacitor D. Transistor
Description : A triac thyristor functions as a control device and is basically ________________. A. two NPN transistors in parallel with a common base lead B. a diode in series with a temperature sensitive capacitor C. two ... -back SCR's with a common gate lead D. a triode tube with an extra heavy grid element
Description : In the illustration, the component VR2 on the A1 AMPLIFIER MODULE is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply from common B. a variable resistor diode to control the output to terminal ... 2 at 9.1 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC
Description : In the illustration, the component VR1 on the A1 AMPLIFIER MODULE is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply from common B. a variable resistor diode to control the output to ... terminal 9 at 6.6 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC
Description : If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ... resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : Unit of flux density in magnetic circuits is ______________. A. Tesla B. dB C. Weber D. Hz
Last Answer : Unit of flux density in magnetic circuits is Weber.
Description : When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming ... the bus D. terminal voltage of the incoming alternator is approaching that of the bus
Description : The purpose of squirrel-cage windings in a synchronous motor is to ______________. A. provide more precise balancing B. produce a higher power factor C. eliminate arcing between the stator and the frame D. provide a means for starting
Description : The purpose of amortisseur windings in a synchronous motor is to ______________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor
Description : In general, polyphase induction motors can be started on full line voltage by means of ______________. A. compensator starters B. autotransformer starters C. across-the-line starters D. primary-resistor starters