Apparatus for detecting changes in the electrical characteristics of sensor devices
US3973257A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 23, 1975 |
| Grant date | Aug 3, 1976 |
| Priority date | — |
| Expiry date | Jan 23, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/04
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The invention relates to electrical apparatus for detecting a change in the electrical characteristics of a sensor device, such as a device for sensing fire, the apparatus comprising a plurality of electrical circuits arranged in parallel and connected to an output circuit which can activate or initiate operation of a device which is required to be operated when the electrical characteristics of the sensor device change, each parallel circuit being provided with means for automatically indicating that the circuit is functioning correctly, any fault in the circuit being automatically indicated and the circuit preventing the output circuit from activating or initiating operation of said device due to a fault.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.