Filament alarm circuit diagram

Use the circuit as shown in the figure to stretch very thin metal wires on both sides of doors and windows, or on both sides of aisles that need to be guarded. When someone breaks into the guarded area, the thin metal wires will be broken unknowingly. Trigger BG and thyristor, alarm DL alarm. For thin metal wire, 0.1MM thick enameled wire can be used. This circuit can also be used as a fire alarm. The method is to hang a wooden block with a rubber band. When the heat of the fire causes the rubber band to stretch, the wooden block breaks the metal wire and triggers an alarm.