Method and apparatus for exciting the driving coils of audible warning devices

US3971017A · kind A · utility

Assignee

• Penelopegay Rowland Absalom

Inventors

• Henry Sutcliffe
• Edward Ball · London, GB

Key dates

• Filing date: Apr 30, 1975
• Grant date: Jul 20, 1976
• Expiry date: Apr 30, 1995

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B3/10
• WIPO field: Control
• WIPO sector: Instruments

Abstract

Although audible devices such as warning devices have been operated from A.C. mains supplies the associated electrical and/or electronic circuitry has been bulky. The invention provides low bulk arrangement comprising first and second capacitor means, the effective capacitance of the two means being in series for connection across an alternating current mains supply, said second capacitor means having connected across it a rectifier and also the series combination of an electronic voltage sensitive switch and the operating means of the warning device, the arrangement being such that, in operation, the charge on the second capacitor means is periodically discharged through said operating means.