High efficiency buzzer
US3945004A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 11, 1974 |
| Grant date | Mar 16, 1976 |
| Priority date | — |
| Expiry date | Jul 11, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B3/10
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An electronic buzzer has a tuned oscillating striker and an electronic oscillator circuit matched to the striker tuned frequency and driving the striker by close coupling of a driving coil to a core member which forms part of an electromagnetic circuit with the striker. The oscillator circuit also includes a control coil in the transistor base circuit and mounted within the driving coil for close coupling to the driving coil and the electromagnetic circuit. The control coil is optimized to have the maximum number of turns while still matching the effective input impedance of the transistor. A diode may be connected in shunt with the driving coil for improved feedback coupling and frequency tuning.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.