GB273485A - Improvements in and relating to buzzers - Google Patents

Abstract

273,485. Igranic Electric Co., Ltd., and Willans, P. W. June 28, 1926. Thermionic modulating systems.- The vibrating-element of a buzzer or vibrator moves in response to variations in plate current of an oscillating thermionic valve, and the grid potential is controlled by the movements of the vibrating- element. As shown in Fig. 1, an oscillatory circuit 3, 4 is connected at three points to the three electrodes of a valve v. The plate connection includes a block condenser 5, and the filament connection an interrupter 1. The direct plate current is fed to the plate through a choke 6 and flows through an electromagnet 2 associated with the interrupter 1. When the switch 1 is closed, plate current flows through the valve and oscillations are generated in the circuit 3, 4. The magnet 2 then attracts the interrupter 1 and opens grid circuit. As the oscillations die away, the grid assumes a negative potential and the cessation or reduction of plate current allows the interrupter 1 to close again. The interrupter is thus kept in vibration. The oscillatory circuit may be a radiating aerial, which will emit an interrupted series of waves. The electromagnet 2 may be in a circuit connected by a transformer to the plate circuit; and the switch 1 may be shunted by a grid leak and condenser.