更多"A transformer in an electric circui"的相关试题:
[单项选择]Capacitance is the property of an electric circuit opposing a change in the （）
A. current in the circuit
B. voltage in the circuit
C. inductance in the circuit
D. resistance in the circuit
[单项选择]Inductance is the property of an electric circuit that （）
A. opposes any change in the applied voltage
B. opposes any change in the current flow through the circuit
C. aids any changes in the applied voltage
D. aids any changes in the current through the circuit
[名词解释]SELV回路（SELV circuit）
[单项选择]An over-speed trip serves to （）
A. stop the engine by cutting off the cooling water supply
B. stop the engine by closing the air intake
C. slow the engine but not stop it
D. slow the engine to half of normal load
[单项选择]The certificate of nationality （） serves as evidence of the nationality of the ship （） shows the port of registry.
A. neither，nor
B. not only，but also
C. not，but
D. not only， and but
[单项选择]Lubricating oil used in a diesel engine serves to（）
A. reduce the wear of bearing surfaces
B. cool the bearing surfaces
C. assist in sealing bearing surfaces
D. all of the above
[单项选择]The purpose of a main switchboard circuit breakers reverse-power trip is to （）.
A. prevent main circuit overload
B. protect the circuit breaker blowout coil
C. prevent alternator motorization
D. prevent low voltage tripout
[单项选择]Electric circuits are protected against overloads and short circuits by means of a/an （）.
A. circuit breaker
B. amplifier
C. diode
D. capacitor
[单项选择]The meat box temperature control circuit, as used in ship service refrigeration system, is an example of （）
A. two position control
B. signal speed floating control
C. proportional control
D. reset control
[单项选择]The total power consumed in a parallel circuit is （）
A. the sum of the powers used in each load (resistor)
B. divided by the number of loads
C. always less than the power used in the smallest load
D. the sum of the powers used in each individual load never more than the power used in the largest load
[单项选择]The total resistance of a parallel circuit is always （）.
A. larger than the greatest branch resistance
B. smaller than the lowest branch resistance
C. equal to the sum of the individual branch resistances
D. one-half the sum of the individual branch resistances
[单项选择]Line losses in a distribution circuit are kept to a minimum by （）.
A. adding rubber insulation conductors to the circuit
B. using higher current and lower voltage increasing the
C. number of thermal relays in the circuit
D. using higher voltage and lower current
[单项选择]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
[单项选择]A heater in the circuit facilitates warning of the engine prior to （） by circulating hot water.
A. starting
B. stopping
C. to start
D. to stop
[单项选择]A ground in an electrical circuit outside the engine room （）.
A. cannot be detected tinder normal conditions
B. is of no consequence to engineering personnel
C. is indicated at the branch circuit breaker panel
D. is indicated by the ground detecting lamps on the main switchboard
[单项选择]The mode of control employed by an alarm circuit is a （）
A. two position control
B. signal speed floating control
C. proportional speed floating control
D. reset control
[单项选择]A circuit breaker and a fuse have a basic similarity in that they both （）.
A. can be reset to energize the circuit
B. should open the circuit when overloaded
C. will burn out when an over current flow develops
D. All of the above
