HOW DOES A REED SWITCH OPERATE?
The reed blades act as magnetic flux conductors when exposed to an external magnetic field from either a permanent magnet or an electromagnetic coil. Contacts in a Form A switch, like shown here, close when the magnetic force exceeds the spring force of the reed blades. As the external magnetic force is reduced, the contacts spring back to the open position. WHAT ADVANTAGES DO REED SWITCHES OFFER? • Low cost and long life • Small size • High signal isolation • Low contact resistance • Millisecond contact operation • Requires no power to operate • Relay and switching functions in one unit • Converts mechanical motion to electrical signals • High voltage holdoff and switching • No-touch switching • Operation is not affected by external contaminants • Safe operation in a hazardous environment • Can be customized to a specific sensitivity and lead configuration REED SWITCH APPLICATION CONSIDERATIONS As a coil is energized or as a magnet approaches a reed switch, it operates. However, the i
