Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971

Magnetic Saturation

Reed Switch with magnet moving perpendicular to it

Magnetic saturation exists when an increase of magnetization applied to a reed contact does not increase the magnetic flux through.

In the case of a magnet actuating a Reed Switch, it is the point at which a Reed Switch attains maximum closure force and moving the magnet any closer will not decrease static contact resistance any further. In the case of a Reed Switch being inside a coil, it is the overdrive beyond which the contact resistance does not drop any further.


Seen in some magnetic materials, saturation is the state reached when an increase in applied external magnetic field H cannot increase the magnetization of the material further, so the total magnetic flux density B more or less levels off. (Though, magnetization continues to increase very slowly with the field due to paramagnetism.) Saturation is a characteristic of ferromagnetic and ferrimagnetic materials, such as iron, nickel, cobalt and their alloys. Different ferromagnetic materials have different saturation levels.

Magnetization curves of 9 ferromagnetic materials, showing saturation.
« Back to Glossary Index