Disconnect anti theft alarm circuit

The circuit utilizes a reed switch KR with a control thyristor V for conduction, along with a 555 integrated circuit configured as a multivibrator to function as an alarm generator. When the door is closed, a permanent magnet is positioned near the reed switch KR, causing the normally closed contacts of the reed switch to open. If the door is forced open, the magnet moves away from KR, allowing thyristor V to conduct and activate the alarm.

The described circuit operates as a security alarm system designed to monitor the status of a door. The key components include a reed switch, a thyristor, and a 555 timer IC. The reed switch KR is a magnetic sensor that opens its contacts when a magnetic field is removed. In this application, a permanent magnet is mounted on the door frame, and when the door is closed, the magnet keeps the reed switch closed, maintaining a low current state.

The 555 timer is configured in a monostable multivibrator mode. In this mode, the timer remains in a stable state until triggered by a change in the status of the reed switch. When the door closes, the reed switch remains closed, and the circuit is inactive. However, if the door is forced open, the permanent magnet is removed from proximity to the reed switch, which causes the switch to open. This action triggers the 555 timer, leading to the conduction of the thyristor V.

The thyristor V serves as the main switching component for the alarm system. Once triggered, it allows current to flow through the alarm circuitry, activating an alarm signal, which can be a siren or a visual indicator. The alarm remains active until the circuit is reset, which can be done manually or through a reset mechanism in the design.

This configuration provides a reliable and efficient means of door monitoring, utilizing simple yet effective components to ensure security. The use of the 555 timer allows for flexibility in timing and response characteristics, making it suitable for various applications in security systems.It uses reed KR V control thyristor conduction, with 555 integrated circuit path consisting multivibrator as an alarm generator. When the door is closed, the permanent magnet close to the reed switch KR, with normally closed contacts reed contacts open,

the thyristor V close - not the police. When the door was forced open, the magnet leave KR, V conduction, namely the police.