单项选择题
A.open B.open front type C.live front type D.None of the above
The （） is a crystal which, under pressure, produces an ...
单项选择题The （） is a crystal which, under pressure, produces an electric current which varies with the pressure.
A.alternator B.glass thermometer C.burdon tube D.piezoelectric pressure transducer
Remote control means that （）.A.the system is manned man...
单项选择题Remote control means that （）.
A.the system is manned manually B.the system is situated remotely from the operator C.the system is controlled automatically D.all the above
Switchboards may be of the dead-front type in which all...
单项选择题Switchboards may be of the dead-front type in which all live parts are installed behind （） and only the operation handles and instruments are on the front.
A.the capstan B.the collector C.the panels D.the surface
