Description : The electrical energy necessary to power a sound-powered telephone's small vibrating bell is obtained from _________. A. the emergency batteries for the general alarm B. each station's hand-cranked generator C. the emergency switchboard D. normal 115 volt DC supplies
Last Answer : Answer: B
Description : Prior to taking a resistance reading with a volt-ohm-milliammeter, the 'zero' setting must be adjusted. After clipping the two leads together, you find the adjustment knob will not return the pointer ... range setting B. weak batteries C. a faulty zero ohms knob D. a faulty meter movement
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
Last Answer : Answer: D
Description : You are calibrating a multimeter using internal batteries to supply power for resistance measurements. However, you are unable to adjust the pointer to 'zero' using the adjustment knob. Therefore, you should ... change scales to the R X 100 scale and adjust using the 'zero ohms' adjusting knob
Last Answer : Answer: A
Description : The unit of electrical resistance is the _____________. A. ampere B. volt C. watt D. ohm
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
Description : Discharge switches are often located on hand-driven meggers. The purpose of these switches is to discharge capacitive charges stored in the _____________. A. megger hand generator B. megger movement coils C. tested equipment while conducting test D. tested equipment after testing
Description : The electrical energy necessary to transmit a person's voice over a sound-powered telephone circuit is obtained from _____________. A. dry cell batteries B. the ship's service switchboard C. the emergency switchboard D. the speaker's voice
Description : An emergency generator, driven by an internal combustion engine, shall be tested under load for a minimum of 2 hours at least once every _____________. A. week B. 2 weeks C. month D. 3 months
Last Answer : Answer: C
Description : Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter
Description : What is the maximum current allowed to be drawn from the secondary of a 2 KVA step-down transformer with a turns ratio of four to one if connected across a 440 volt line? A. 1.1 amps B. 4.5 amps C. 18.1 amps D. 22.7 amps
Description : What is the maximum allowable primary current of a 2 KVA step-down transformer with a four to one turns ratio if connected across a 440 volt line? A. 1.1 amps B. 4.5 amps C. 18.1 amps D. 27.7 amps
Description : In the illustration, A, B, C and D are 12 volt batteries. a voltmeter across the output of the circuit will indicate _____________. EL-0039 A. 6 volts B. 12 volts C. 24 volts D. 48 volts
Description : Before using an all-purpose electric measuring instrument (multimeter) utilizing internal batteries to supply power for resistance measurements, you should FIRST ____________. A. remove one of the ... batteries C. calibrate using a known external resistance D. select the proper resistance range
Description : A milliammeter, with a full scale deflection reading of 100 milliamps, is known to have an accuracy of + or - 2%. A meter reading of 10 milliamps would indicate a line current of between _____________. A. 9.8 ... 9.8 and 10.2 milliamperes C. 8.0 and 12.0 milliamperes D. 8.0 and 10.0 milliamperes
Description : If there is a reduction in the normally supplied frequency to a 120/240 volt, threephase AC current motor from 60 hertz to 55 hertz, the motor would _____________. A. run at a slower speed B. operate at a lower current C. overheat D. trip off the line
Description : The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. ... in series with the load D. balance coil diverting neutral current through the shunt field
Description : The hook-on AC volt-ammeter consists essentially of a split-core and a rectifiertype instrument connected to the secondary winding of a _____________. A. potential transformer B. control transformer C. current transformer D. reactance transformer
Description : A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with _____________. A. both meters in series with the ... parallel with the resistance D. the ammeter in parallel and the voltmeter in series with the resistance
Description : A capacitor is to be tested with a megohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value ... and gradually decrease D. swing to zero then gradually increase with slight pointer movements down scale
Description : The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is ... starting up the machine D. every 30 days whether the machine is in use or not
Description : In the illustrated circuit 'A', what power is consumed by a 3 ohm resistor with a 12 volt source? EL-0041 A. 12 watts B. 48 watts C. 64 watts D. 232 watts
Description : The doorbell on your house requires a 12 volt alternating current. A transformer having a primary winding of 1,600 turns is to be used to step down your house's 110-volt alternating current. How many turns are there on the secondary winding?
Last Answer : ANSWER: 175 TURNS
Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead
Description : If reading AC current with the illustrated device and unsure of the range as a precaution , the first step should be to _________. EL-0047 A. secure power and test for voltage B. disconnect the ... resistance and use Ohm's law to calculate current D. unable to safely measure current with the device
Description : To properly use a hook-on-type volt/ammeter to check current flow, you must FIRST _____________. A. de-energize the circuit to allow connection of the instrument in series B. hook the jaws ... test leads to the appropriate terminals D. short the test leads and calibrate the instrument to zero
Description : Two batteries A and B each of e.m.f. 2 V are connected in series to an external resistance R = 1 ohm . If the internal resistance of battery A is 1.9
Last Answer : Two batteries A and B each of e.m.f. 2 V are connected in series to an external resistance R = 1 ohm . If the ... V B. `3.8` V C. zero D. `4.8` V
Description : When troubleshooting most electronic circuits, 'loading effect' can be minimized by using a voltmeter with a/an ___________________. A. input impedance much greater than the impedance across which the voltage ... sensitivity of less than 1000 ohms/volt D. sensitivity of more than 1000 volts/ohm
Description : The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________. A. prime mover speed B. exciter output voltage C. load on the alternator D. number of poles
Description : Caution must be exercised during the charging of lead-acid storage batteries as _____________. A. the acid will become weaker B. hydrogen gas is being continuously liberated C. both plates are changing chemically to lead sulfate D. lead peroxide in the negative plate is poisonous
Description : When a transformer is used to step down voltage, the low voltage winding is _____________. A. part of the core B. the primary coil C. not insulated D. the secondary coil
Description : When using a multimeter for resistance measurements, it should be calibrated by clipping the loose ends of the leads together and _____________. A. setting the instrument pointer at 'zero' ohms B. ... the plus and minus terminals D. using a special purpose resistance measuring instrument (a bridge)
Description : Sound powered telephone units 'I', 'II', and 'III' of the circuit shown in the illustration are for 'station numbers' _____________. EL-0093 A. 2, 4 and 6 B. 1, 2 and 3 C. 3, 5 and 8 D. 1, 2 and 6
Description : The heaters for the winch circuit shown in the illustration are powered from _____________. EL-0102 A. a separate source B. the winch main bus C. the master switch power circuit D. the contactor control circuit
Description : A capacitor can be tested using a megohmmeter or an ohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance ... deflect to and remain at zero D. immediately swing to a high reading and then gradually decrease
Description : What is the total current in the illustrated circuit with a 6 volt battery if the resistance of R1 is 2 ohms, R2 is 4 ohms, and R3 is 4 ohms? EL-0021 A. 0.6 amp B. 1 amp C. 4 amps D. 6 amps
Description : Calculate the resistance of shunt required to make a milliammeter which gives maximum deflection for a current of 15 mA and which has a resistance of 5 Ω; read up to 10 Amp.
Last Answer : Answer :
Description : An alternator is being paralleled with one on the line. At the INSTANT the circuit breaker is closed, the frequency of the incoming alternator will normally _____________. A. increase B. not change C. decrease D. be exactly 60 hertz
Description : The electrical schematic shown in the illustration indicates the lighting feeder circuit is _____________. EL-0014 A. three phase, 450 volt, and 60 cycle B. three phase, 120 volt, and 60 cycle C. single phase, 120 volt, and 60 cycle D. not specified
Description : A volt-ohm-millimeter can be used to check for ____________. A. continuity B. grounds C. voltage D. all of the above
Description : A megger is being used to test the insulation of an AC generator. The resistance value of a dry, clean winding will _____________. A. continue to rise as test potential is maintained, ... , becoming fairly steady after 5-7 minutes D. stabilize after approximately 2-4 minutes of fluctuation
Description : Coast Guard Regulations (46 CFR) require that each alternating current generator arranged for parallel operation shall be provided with _____________. A. more than one means of excitation B. individual circuit fuses C. a high back-pressure trip D. a reverse-power trip
Description : If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring
Description : The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator
Description : When a battery-charging panel is being used, the batteries will discharge if _____________. A. DC voltage is supplied B. the polarity is reversed C. the voltage fluctuates D. too little current is supplied
Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer _____________. A. dipping toward ... kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading
Description : What can be used to replace the exciter in the circuit shown in the illustration? EL-0101 A. A step-up transformer. B. A rectifier. C. A step-down transformer. D. An operational amplifier.
Description : Under normal conditions, storage batteries used for starting the emergency diesel generator are maintained in a charged state by which of the following methods? A. Trickle charging B. Fast charging C. Equalizing charge D. Reverse charging
Description : As shown in the illustration, the circuit has been on the line for several days when component 'E1' burns out. The operator receives an alarm, switches over 'B' to energize the standby ... than required for the circuit therefore limiting the current through the alarm relay which will not pick up
Description : A d.c. source has an open circuit voltage of 30 V and an internal resistance of 1.5 Ohm. A resistive load is connected to the source. Maximum power dissipated in the load is (A) 300 W (B) 150 W (C) 45 W (D) 20 W
Last Answer : A d.c. source has an open circuit voltage of 30 V and an internal resistance of 1.5 Ohm. A resistive load is connected to the source. Maximum power dissipated in the load is 150 W