RANDOM PAGE
SITE SEARCH
LOG
IN
SIGN UP
HELP

Reed Switch

This is the AQA version closing after June 2019. Visit the the version for Eduqas instead .

To gain access to revision questions, please sign up and log in.

Everyone:
Switches
Fuses
Microswitches
RCD
Reed
Relays
Tilt

This rather fragile switch is normally open (NO). If a magnet it positioned near the metal contacts, the magnetic field causes the contacts to attract each other and the switch turns on.

This device is often found in door and window alarms. When the door is opened the magnet (in the door) moves away from the switch (in the door frame). This breaks the circuit and the alarm sounds.

The glass tube is filled with an inert gas so corrosion is minimised. This makes reed switches more reliable.

Reed Switch