Tone generator
US4257036A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1979 |
| Grant date | Mar 17, 1981 |
| Priority date | — |
| Expiry date | Nov 27, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R13/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A tone generator for producing an audible sound for a predetermined time period in response to the occurrence of one or more predetermined conditions. The tone generator comprises a diaphragm mounted within a resonant sound cavity that is activated by an electromagnetic assembly which is in turn driven by the output signal from an oscillator circuit. The control logic and timing circuit for the tone generator includes a unique PTC subassembly that provides a timed logic signal for controlling the activations of the diaphragm, as well as an independently generated signal for contemporaneously activating a lamp which provides a visual indication of the detected predetermined condition. The control logic and timing circuit is adapted to produce the proper timed logic signal despite the absence of a lamp in the circuit or a lamp failure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.