A rotatable electrode is inserted between {HEAD ~ these fixed electrodes}, and this rotatable electrode is mounted on {TAIL ~ a shaft} which is rotatably provided on the housing 
A rotatable electrode is inserted between { HEAD ~ these fixed electrodes } , and this rotatable electrode is mounted on { TAIL ~ a shaft } which is rotatably provided on the housing
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH