单项选择题
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
A direct current passing through a wire coiled around a...
单项选择题A direct current passing through a wire coiled around a soft iron core is the description of a simple（）.
A.magnetic shield B.electromagnet C.piezoelectric device D.electromagnetic domain
