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A simple electromagnetic door holder consists of a strong electromagnet, usually attached to a wall or mounted in a floor pedestal enclosure, next to the door it controls. The mechanism may be mounted near the floor, at the upper corner of the open door, or at any convenient height along the latch edge (away from the hinged edge).
Wireless home alarm system control panel A house alarm. A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary or property damage, as well as against intruders.
Commonly-used circuit symbol Operation of the reed switch The reed switch [ i ] is an electromechanical switch operated by an applied magnetic field . It was invented in 1922 by professor Valentin Kovalenkov at the Petrograd Electrotechnical University , [ 1 ] and later evolved at Bell Telephone Laboratories in 1936 by Walter B. Ellwood into ...
Door and window sensors are also implemented in most home security systems. One part of the system is installed on the door or window itself while the other part is installed on the frame of the door or window. The two part system connects securely when a door or window is closed, creating a security circuit. [5]
A quick demonstration of an electronic door lock. An electronic lock (or electric lock) is a locking device which operates by means of electric current. Electric locks are sometimes stand-alone with an electronic control assembly mounted directly to the lock.
Fire alarm bell. Fire alarm bells are divided into two categories: vibrating, and single-stroke. On a vibrating bell, the bell will ring continuously until the power is cut off. When power is supplied to a single-stroke bell, the bell will ring once and then stop. It will not ring again until power is turned off and on again.
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An automotive wiring diagram, showing useful information such as crimp connection locations and wire colors. These details may not be so easily found on a more schematic drawing. A wiring diagram is a simplified conventional pictorial representation of an electrical circuit. It shows the components of the circuit as simplified shapes, and the ...