Reed Switch Level Sensor Circuit

A reed switch is a sensor that closes the circuit in the presence of a magnetic field.

Reed switch level sensor circuit.

The contacts are usually normally open closing when a magnetic field is present or they may be. However reed switches can be fragile to use directly hence this module can make it easier to handle and mount the sensor in various applications. In its simplest and most common form it consists of a pair of ferromagnetic flexible metal contacts in a hermetically sealed glass envelope. The reed switch is an electrical switch operated by an applied magnetic field it was invented at bell telephone laboratories in 1936 by walter b.

Reed sensors can be used in many applications where contactless on off is required. How to use magnetic sensor and reed switch in projects a magnetic field from an electromagnet or a permanent magnet will cause the reeds to attract each othe. The pcb tracks can be designed in such a way that a full tank gives high resistance and an empty tank gives low resistance or vice versa. Some fluid level sensors in clothes washing machines and dishwashers use floating magnets that bob up past reed switches to switch off the valves when enough water is inside.

When the magnetic force line of the magnetic float acts on a certain position of the liquid level gauge the reed switch in that position is closed.