Dual line electret transducer
US4040044A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1976 |
| Grant date | Aug 2, 1977 |
| Priority date | — |
| Expiry date | Aug 30, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/26
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An improved low-cost line transducer comprises a pair of electret covered conductors twisted about each other to form longitudinal helices and mechanically coupled to a medium that transmits mechanical forces transversely of the conductors. A change in the conductor-electret spacing caused by the mechanical disturbance generates an electrical signal between the conductors which is detected and processed by appropriate circuitry for indicating the occurrence of the disturbance. This simplified line transducer has improved sensitivity to the low frequency disturbances because of the non-symmetrical relation of the two conductors throughout their length. Undesired hum and noise picked up by the unshielded line is reduced or eliminated by appropriate circuits in the signal processor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.