A circuit breaker and a fuse have a basic similarity(类似) in that they both ______.A.can be reset to energize the circuitB.should open the circuit when overloadedC.will burn out when an over current flow developsD.should short the circuit when overloaded
A circuit breaker and a fuse have a basic similarity(类似) 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.should short the circuit when overloaded
相关考题：
When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is _____.A.laggingB.leadingC.maximumD.minimum
For (71) service, we need a virtual-circuit subnet. Let us see how that works. The idea behind virtual circuits is to avoid having to choose a new (72) for every packet sent. Instead, when a connection is established, a route from the (73)machine to the destination machine is chosen as part of the connection setup and stored in tables inside the (74) That route is used for all traffic flowing over the connection, exactly the same way that the telephone system works. When the connection is released, the virtual circuit is also terminated. With connection-oriented service, each packet carries an (75) telling which virtual circuit it belongs to.A．connectionlessB．connection-orientedC．datagramD．telegram
On an ONS 15454 node you can tunnel an (). A. SDH circuit over a SONET network delivering it as an SDH signalB. SDH circuit over a SONET network delivering it as a SONET signalC. SONET circuit over an SDH network delivering it as an SDH signalD. SONET circuit over an SDH network delivering it as a SONET signal
A circuit breaker and a fuse have a basic similarity in that they both______.A.can be reset to energize the circuitB.should open the circuit when overloadedC.will burn out when an over current flow developsD.should short the circuit when overloaded
A circuit breaker differs from a fuse in that a circuit breaker ______.A.melts and must be replacedB.is enclosed in a tube of insulating material with metal ferrules(环) at each endC.gives no visual indication of having opened the circuitD.trips to break the circuit and may be reset
If an attempt is made to hoist a load that exceeds the capacity of an electric winch，an overload safety device causes a circuit breaker to cut off the current to the winch motor ______．A.when the line pull reaches the rated winch capacityB.after the line pull exceeds the rated winch capacityC.after a short build-up of torqueD.immediately
Running an electric winch at slow speed over a long period of time causes ______．A.the speed to be retarded by the friction brakeB.a load to go downward at full speedC.the circuit breaker to turn offD.the resistors to overheat and eventually burn out
On an ONS 15454 node you can tunnel a（n） （）.A、 SDH circuit over a SONET network delivering it as an SDH signalB、 SDH circuit over a SONET network delivering it as a SONET signalC、 SONET circuit over an SDH network delivering it as an SDH signalD、 SONET circuit over an SDH network delivering it as a SONET signal
For (1) service, we need a virtual-circuit subnet. Let us see how that works. The idea behind virtual circuits is to avoid having to choose a new (2) for every packet sent. Instead,when a connection is established, a route from the(3) machine to the destination machine is chosen as part of the connection setup and stored in tables inside the (4) . That route is used for all traffic flowing over the connection, exactly the same way that the telephone system works.When the connection is released, the virtual circuit is also terminated. With connection-oriented service, each packet carries an (5) telling which virtual circuit it belongs to.空白（5）处应选择（）A、addressB、identifierC、interfaceD、element
On an ONS 15454 node you can tunnel an （）.A、SDH circuit over a SONET network delivering it as an SDH signalB、SDH circuit over a SONET network delivering it as a SONET signalC、SONET circuit over an SDH network delivering it as an SDH signalD、SONET circuit over an SDH network delivering it as a SONET signal
单选题When the voltage remains constant and the resistance is increased in a series circuit, the flow of current （）Aincreases by the square of the original valueBincreasesCremains the sameDdecreases
单选题If an attempt is made to hoist a load that exceeds the capacity of an electric winch，an overload safety device causes a circuit breaker to cut off the current to the winch motor（）.Awhen the line pull reaches the rated winch capacityBafter the line pull exceeds the rated winch capacityCafter a short build-up of torqueDimmediately
单选题In a simple series circuit, the entire source voltage will drop across （）Athe resistor next to the negative terminalBa short circuitCthe resistor next to the positive terminalDan open circuit
单选题A circuit breaker differs from a fuse in that a circuit breaker （）.Amelts and must be replacedBis enclosed in a tube of insulating material with metal ferrules at each endCgives no visual indication of having opened the circuitDtrips to break the circuit and may be reset
单选题A circuit breaker and a fuse have a basic similarity in that they both （）.Acan be reset to energize the circuitBshould open the circuit when overloadedCwill burn out when an over current flow developsDAll of the above
单选题If the resistance of a circuit is cut in half and the applied voltage is kept constant, the current flow will be （）.AdoubledBquadrupledCunchangedDcut in half
单选题When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is （）AlaggingBleadingCmaximumDminimum
单选题When securing an AC generator, you should FIRST （）.Aopen the generator circuit breakerBswitch the voltage regulator to “manual”Cdecrease the field excitation to minimumDreduce the load on the unit
单选题The purpose of a main switchboard circuit breakers reverse-power trip is to （）.Aprevent main circuit overloadBprotect the circuit breaker blowout coilCprevent alternator motorizationDprevent low voltage tripout
单选题Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air?（）AOpen the machine on both ends so as to allow the air and dust to escapeBBe certain that the circuit breaker is opened and tagged on the feeder panelCBe certain that the air is clean and as dry as possibleDAll of the above
单选题Fuses placed in series with a thermal trip-type circuit breaker are used for （）.Atime-delay protectionBshort-circuit protectionCshort duration surge protectionDsustained overload protection
单选题Before any work on electrical or electronic equipment is performed, which of the following precautions should be carried out （）ADe-energize the applicable switchboard busBBypass the interlocksCSecure and tag the supply circuit breaker in the open positionDStation a man at the circuit supply switch
单选题Inductance is the property of an electric circuit that （）Aopposes any change in the applied voltageBopposes any change in the current flow through the circuitCaids any changes in the applied voltageDaids any changes in the current through the circuit
单选题When two different metals are joined to form a closed circuit and exposed to different temperatures at their junctions （） which can be used to measure temperature.Aa current will flowBa power will developCa heat will flowDa pressure will produce
单选题When working on a high voltage circuit, you should always have another person present with you.This person should have a good working knowledge of （）Athe circuit being worked on and the location of all switches and circuit breakers controlling itBfirst-aid techniques for treating electrical shockCcardiopulmonary resuscitation (CPR)DAll of the above
单选题A transformer in an electric circuit serves to （）Agenerate its own electrical powerBtransform electrical energy into mechanical energyCincrease or decrease circuit voltage as requiredDconvert AC current to DC current