发明名称 |
Electronic monitoring system stabilized against accidental triggering |
摘要 |
A contactless motion detector, including an oscillator sensitive to an approaching metallic element, includes an electronic switch such as a thyristor triggerable by an output signal from a demodulator comprising a storage capacitor which is alternately chargeable and dischargeable, preferably with constant current, during each cycle of a high-frequency voltage generated by the oscillator. The oscillator voltage is compared with a reference voltage by means of a differential amplifier causing the flow of a charging current into the capacitor when the oscillator voltage exceeds the reference voltage whereas a discharging current flows out of that capacitor in the opposite case. The reference voltage is so chosen that the capacitor charge rises in the course of a few cycles above a predetermined threshold when the oscillator voltage is high but remains below that threshold when it is low.
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申请公布号 |
US4336491(A) |
申请公布日期 |
1982.06.22 |
申请号 |
US19810232186 |
申请日期 |
1981.02.06 |
申请人 |
I F M ELECTRONIC GMBH |
发明人 |
BUCK, ROBERT;OZECH, INGO S. |
分类号 |
H03K17/945;H03K17/95;(IPC1-7):H01H36/00 |
主分类号 |
H03K17/945 |
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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