Capacitive detector device and alarm system
US5764145A · kind A · utility
Inventors
Key dates
| Filing date | Jun 27, 1996 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Jun 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96073
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive detector is provided which includes an antenna for detecting small capacitive changes in an electric or electromagnetic field surrounding the antenna, and particularly to an alarm system which uses the capacitive detector to generate an alarm signal upon detection of capacitive changes in the generated electric or electromagnetic field. The detector is realized with an antenna connected to an electronic circuitry which generates an electric field around the antenna. The electronic circuitry generates an electric or electromagnetic field around the antenna, builds up a balanced electric field around the antenna, maintains the generated electric or electromagnetic field around the antenna balanced, prevents the detector device from being affected by changes in temperature and humidity, detects small changes in the generated electric field around the antenna, and indicates that a change in the generated electric field has occurred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.