Alarm silencing circuitry for photoelectric smoke detectors
US5422629A · kind A · utility
21Cited by
8References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1992 |
| Grant date | Jun 6, 1995 |
| Priority date | — |
| Expiry date | Mar 3, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/145
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A silencable photoelectric-type detector includes a source of radiant energy and a detector. A generator circuit provides a sequence of pulses to energize the source. A biasing circuit biases the detector. The detector can be temporarily silenced, when in alarm, by reducing the energy level of the pulses or altering the bias point of the detector for a period of time. The period of time can be established by an RC circuit. The effect of the energy level reduction or the bias point alteration is to reduce the sensitivity level of the detector temporarily.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.