SMOKE AND FIRE ALARM Russian patent published in 2005 - IPC

FIELD: fire alarms, particularly to detect increase in optical air density on the base of infrared light dispersion intensity.

SUBSTANCE: alarm comprises inverter, the second current-limiting member connected with other network elements, which provide forming short light impulses with long impulse spacing by light-emitting-diode indicator in standby operational state. Degree of smoke and fire alarm and voltage in loop circuit to which smoke and fore alarm is connected can be judged from above optical signal. The first current switch in stable standby operational state provides stable impulse amplitude of current going through light-emitting-diode when supply voltage in loop circuit of smoke and fire alarm varies and when voltage drop value varies in above diode.

EFFECT: improved reliability of device workability control.

2 cl, 1 dwg