发明授权
- 专利标题: Fail-safe timing circuit
- 专利标题(中): 故障安全定时电路
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申请号: US919093申请日: 1978-06-26
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公开(公告)号: US4150417A公开(公告)日: 1979-04-17
- 发明人: John O. G. Darrow , William R. Popp
- 申请人: John O. G. Darrow , William R. Popp
- 申请人地址: PA Swissvale
- 专利权人: Westinghouse Air Brake Company
- 当前专利权人: Westinghouse Air Brake Company
- 当前专利权人地址: PA Swissvale
- 主分类号: B61L21/06
- IPC分类号: B61L21/06 ; H01H47/32 ; H03K17/28 ; B61L1/08 ; B61L21/00 ; H03K5/153
摘要:
This disclosure relates to a fail-safe timing circuit having a regulator which produces a regulated d.c. voltage when a switch is closed. A signal generator powered by the regulated d.c. voltage for producing square-wave signals. A two-stage amplifier for amplifying the square-wave signals which are fed to a dual rectifier network which produces a positive d.c. voltage and a regulated negative fail-safe d.c. voltage. A pulse generator powered by the positive d.c. voltage for producing signal pulses having an unequal duty cycle. A charging circuit connected to the regulated negative d.c. voltage, and a trigger circuit for periodically sampling the potential charge on the charging circuit. An amplifier for amplifying periodic pulses which are produced during the sampling of the potential charge. A level detector for producing a.c. oscillations when the level of the periodic pulses exceeds a predetermined value, an amplifier for amplifying the a.c. oscillations, and a rectifier for rectifying the amplified a.c. oscillations to produce a d.c. output voltage for energizing a relay upon expiration of a given time interval after the switch is closed.
公开/授权文献
- US5850025A Protection of plants against plant pathogens 公开/授权日:1998-12-15