To protect your home, vehicles or even objects, what we present is a sensitive alarm circuit that we found in a 1982 publication. This circuit triggers a siren, an audio oscillator or even a higher power circuit, when an invisible thin wire is inadvertently interrupted by the thief or intruder. As the supply is made with a battery, if we also use a battery-powered warning system, we will have the possibility of portable use or independent of the network. The interruption of the thin protective wire causes transistor 01 in the circuit to conduct a strong current that activates a relay (RL1). This relay is used to trigger an SCR next for protection reasons (if the connection is reestablished by the intruder the alarm will not stop ringing).
