发明名称 |
Electrometer probe |
摘要 |
A detecting electrode (22) is formed on a substrate (28), an amount of potential from a charged surface (23) induced in the detecting electrode (22) corresponding to a potential on the surface (23). A guard electrode (26) formed on the same surface of the substrate (28) as the detecting electrode (22) surrounds the detecting electrode (22). Part of the guard electrode (26b) is formed on the back surface of the substrate (28). The detecting electrode (22) is connected to a non-inverting input of an operational amplifier (24). The output of the operational amplifier (24) is connected to the inverting input thereof and also to the guard electrode (26) to produce unity gain and place the guard electrode (26) at the same potential as the detecting electrode (22). The substrate (28) is formed of a material such that the electrical resistance between the detecting electrode (22) and the guard electrode (26) is at least 109 ohms to reduce zero drift to a negligible value.
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申请公布号 |
US4318042(A) |
申请公布日期 |
1982.03.02 |
申请号 |
US19800120581 |
申请日期 |
1980.02.11 |
申请人 |
RICOH COMPANY, LTD. |
发明人 |
EDA, TADAHIRO;TATSUMI, SUSUMU;IMAI, CHIKARA |
分类号 |
G01R29/12;(IPC1-7):G01R31/02 |
主分类号 |
G01R29/12 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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