单项选择题
A.Fan B.Pump C.Winch D.Machine tool
One factor that determines the frequency of an alternat...
单项选择题One factor that determines the frequency of an alternator is 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
The device that most commonly utilizes the principle of...
单项选择题The device that most commonly utilizes the principle of electromagnetic induction is the（）.
A.diode B.transformer C.transistor D.rheostat
Which of the listed devices is used to measure pressure...
单项选择题Which of the listed devices is used to measure pressure and convert it to an electrical signal?（）
A.Transducer B.Reducer C.Transformer D.Rectifier
