Electronic monitoring system with direct-current power supply
US4551637A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1983 |
| Grant date | Nov 5, 1985 |
| Priority date | — |
| Expiry date | Apr 21, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/945
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A contactless motion detector is energized in series with a load from a source of direct current via a pair of supply leads connected across a binary switching circuit in parallel with a voltage-generating network designed to deliver operating current to the detector in either switching position. The switching circuit comprises a main electronic switch, designed as a transistor, which is turned on or off by an output signal of the detector and in turn controls an ancillary electronic switch (transistor or thyristor) whose conduction intensifies the load current. When both electronic switches are transistors, they are interconnected in a positive-feedback loop driving them into conduction as soon as the main transistor is turned on; the base current of the ancillary transistor then contributes significantly to the load current while its collector current helps maintain the energization of the detector. The voltage-generating network includes a current limiter as well as a constant-voltage generator, e.g. a Zener diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.