（）的英语是voltage。A、电压B、电阻C、电流D、电器
（）的英语是voltage。
- A、电压
- B、电阻
- C、电流
- D、电器
相关考题：
The main difterence between a motor control circuit containing low voltage protection and low voltage release is that the latter contain A.a magnetic operating coilB.normally open line contactsC.thermal-overload protectionD.a momentary-contact start button
WhichstatementsistrueaboutForeignExchangeStation(FXS)portsonarouter?() A.theFXSinterfaceallowsananalogconnectiontobedirectedatthepublicswitchedtelephonenetwork（PSTN’s）centralofficeB.theFXSinterfaceconnectdirectlytoastandardtelephone，faxmachine，orsililardeviceandsuppliesring，voltage，anddialtoneC.theFXSinterfaceconnectdirectlytoanIPphoneandsuppliesring，voltage，anddialtoneD.theFXSinterfaceconnectdirectlytoISDNvoicechannels
材料：The field current supply in older machines comes from a lower voltage direct current generator or exciter on the same shaft as the alternator. Modern machines however are either statically excited or of the high-speed brush-less type. The exciter is required to operate to counter the effects of power factor for a given load. The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle. With a purely resistance load the voltage and the current are in phase, giving a power factor of one. The power consumed is therefore the product of voltage and current. Inductive or capacitive loads, combined with resistance loads, produce lagging or leading power factors which have a value less than one.The power consumed is therefore the product of current, voltage and power factor. The alternating current generator supplying a load has a voltage drop resulting from the load. When the load has a lagging power factor this voltage drop is considerable. Therefore the exciter, in maintaining the alternator voltage, must vary with load current and also the power factor. The speed change of the prime mover must also be taken into account.问题： The word “machines” in the passage refers to _____.A.the direct current generatorB.the alternating current generatorC.the exciterD.the prime moverWhich of the following statements is true according to the passage ?A.With a purely resistance load, the power factor is zeroB.Inductive loads combined with resistance loads produces leading power factorsC.Capacitive loads combined with resistance loads produces lagging power factorsD.With a purely resistance load, the phase angle is zeroWhen the load has a lagging power factor this voltage drop is considerable. This sentence means that _____.A.with a purely resistance load, the voltage drops too muchB.there is a considerable voltage drop in the capacitive load combined with resistance loadC.when the load is the capacitive load combined with resistance load, the voltage drops to zeroD.when the load is the inductive load combined with resistance load, the voltage drop is fairly largeThe exciter must vary with: ① load current ② the power factor, ③ speed change of the prime mover.A.①B.②C.①②D.①②③请帮忙给出每个问题的正确答案和分析，谢谢！
According to Ohm’s Law， which of the following is correct？（）A、As voltage increases， resistance decreasesB、As amperage decreases， resistance decreasesC、As resistance decreases， amperage increasesD、As resistance increases， voltage increases
Which of the following technologies was created to reduce cost, increase cable length, and uses 3.3v across the line?（）A、Wide-Ultra2 SCSI-3B、High-Voltage DifferentialC、Low-Voltage DifferentialD、Fibre Channel
单选题The output voltage of a three-phase alternator is regulated by the （）.AAC voltage to the armatureBAC voltage to the fieldCDC voltage to the armatureDDC voltage to the field
单选题If a technician suspects that the voltage being delivered to a desktop computer’s power supply is insufficient or incorrect, which device should be used to determine the correct voltage?（）AA power supply testerBA multimeterCA loopback adapterDA cable tester
单选题Which of the following technologies was created to reduce cost， increase cable length， and uses 3.3v across the line？（）A Wide-Ultra2 SCSI-3B High-Voltage DifferentialC Low-Voltage DifferentialD Fibre Channel
单选题Which of the listed items will stop a motor due to a reduction in voltage and restart it when the voltage is restored to normal?（）ALow voltage protection circuitBNon-renewable link fuseCRenewable link fuseDLow voltage release circuit
单选题The instantaneous reduction in voltage of an AC generator, resulting from an increase in load, and prior to the automatic voltage regulator correcting the situation, is called voltage （）.AdroopBdropCdipDregulation
单选题With a （） load the voltage and current are in phase.Apure resistanceBcapacitiveCinductiveDNone of the above
单选题Prior to starting an AC generator prime mover, the voltage regulator cutout switch should be placed in the （）Amanual positionBbus neutral positionCraise voltage positionDtransfer position
单选题Possible phase relationships between voltage and current in an alternating current circuit include which of the following conditions?（）ACurrent and voltage may be in phaseBCurrent may lead the voltageCCurrent may lag the voltageDAll of the above
单选题The alternating current generator supplying a load has a voltage drop resulted from the loadWhen the load has a lagging power factor this voltage drop （）.Ais smallBmay be neglectedCis usefulDis considerable
单选题Which of the following technologies was created to reduce cost, increase cable length, and uses 3.3v across the line?（）AWide-Ultra2 SCSI-3BHigh-Voltage DifferentialCLow-Voltage DifferentialDFibre Channel
单选题A fuse that blows often should be replaced only with a fuse of （）.Athe recommended current and voltage ratingBhigher current and voltage ratingChigher current and lower voltage ratingDlower current and higher voltage rating
单选题The voltage developed by an AC generator is controlled by varying the （）Aspeed of the prime moverBAC excitation to the fieldCDC excitation to the fieldDDC excitation of the voltage regulator
问答题什么是 device breakdown voltage？