單項選擇題The most inefficient method of voltage reduction from the stand point of power loss, is a/an （）

A.capacitor in series with the load
B.inductor in series with the load
C.capacitor and inductor in series with the load
D.resistor in series with the load


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1.單項選擇題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

2.單項選擇題The division of kilowatt load between two paralleled alternators is determined by the （）

A.amount of field excitation of the leading machine
B.load-speed characteristics of the governors
C.amount of field excitation to the lagging machine
D.type of alternator

3.單項選擇題The division of the kilowatt load between two AC generators operating in parallel is controlled by the settings and characteristics of the （）.

A.voltage regulators
B.field rheostats
C.reverse power relays
D.prime mover governors

4.單項選擇題In a three-phase circuit, the phase voltages are （）

A.120°apart
B.160°apart
C.180°apart
D.360°apart

5.單項選擇題The frequency of an alternator at a given RPM is determined by the （）.

A.number of turns of wire in the armature coil
B.number of magnetic poles
C.strength of the magnets used
D.output voltage