| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a to-be-detected AC voltage of a to-be-detected object without calculating an electrostatic capacitance between a detection electrode and the to-be-detected object. SOLUTION: A voltage detector comprises: the detection electrode 2 capacitively coupled to the to-be-detected object 6; a reference signal output section 4 for outputting a reference signal Ss; a detection section 3 connected to the detection electrode 2, inputting the reference signal Ss, and outputting a detection signal S1 whose amplitude is varied in response to both current values of a to-be-detected current Iv1 flowing based on the AC voltage V1 and a reference current Is1 flowing based on the reference signal Ss; and a signal extraction section 5 for amplifying the detection signal S1 at a predetermined gain, generating an amplified detection signal S3, controlling the gain so as to cancel the reference signal Ss and a signal component of the reference signal Ss contained in the amplified detection signal by adding the reference signal Ss and the amplified detection signal S3, extracting a signal component of the AC voltage V1 from the amplified detection signal S3, and outputting it as an output signal So. The reference signal output section 4 integrates the detection signal S1 and outputs the reference signal Ss. COPYRIGHT: (C)2011,JPO&INPIT |
