單項(xiàng)選擇題If both the “high level” and “l(fā)ow level” alarms come on for the same address of a centralized control console, the most likely problem is a/an （）.

A.sensor failure
B.failed alarm
C.low level
D.extremely high level


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1.單項(xiàng)選擇題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

2.單項(xiàng)選擇題Which is a function of the voltage regulators used with AC generators?（）

A.To cut out generators when they are no longer required
B.To cut in additional generators automatically as required
C.To divide the KW load equally between generators operating in parallel
D.To divide reactive current between generators operating in parallel

3.單項(xiàng)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

4.單項(xiàng)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

5.單項(xiàng)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