Learn how the magnet activates the Intruder Alarm! A fun construction to discover how a magnetic switch works in the electrical circuit! 

HOW IT WORKS: Activate the alarm and close the door. If someone opens the door even a small crack, the alarm will sound. Close the door again or deactivate the alarm to stop the buzzer. When the door is closed and the triangles in the magnet holder and the base align, the disc is attracted by the magnet to one side of the hole area. When the door opens, the magnet moves away from the base and the attraction from the magnet is no longer strong enough to hold the disc. The disc rolls down to the bottom of the hole area and remains between the two plates with holes. This acts as a switch, completing the circuit and allowing current to flow through the buzzer.

CONTENTS: Part A: Base x 1, Part B: Cover x 1, Part C: Magnet x 1, Part D: Magnet holder x 1, Part E: Hole plate set x 1, Part F: Battery cover x 1, Part G: Adhesive tape, Part H: Metal disc x 1, Part I: Terminal covers x 3, Part J: Screws x 3, Part K: Washer screws x 2. Also required but not included in this package: 2 AAA 1.5V batteries, a small screwdriver. Instructions included in Greek.