• A magnet moved perpendicularly towards and away from a reed switch turns it off and on one time.
• A magnet moved parallel to a reed switch operates it from one to three times. (Linear motion; see Basic Reed Theory and Use)
• A magnet swung towards and away from a reed switch operates it one time.

Reeds are constructed with ferromagnetic metal leads. This metal becomes magnetic in a magnetic field. When this happens, each lead assumes opposite magnetic polarity. The leads attract one another and when the field strength is sufficient to overcome mechanical lead stiffness, the leads make contact. An electrical connection is then made. This action happens in as little as 0.5 mS. Reed sensitivity is built in by the manufacturer and determines how strong a magnetic field must be to close the reed leads. Magnetic field strength is measured in Gauss and reed sensitivity is measured in Ampere-Turns. These units are not mathematically related, but through experience can be matched empirically. When a magnet is brought into proximity to the reed, physical alignment is important. Call us for more detailed information on magnet alignment. Electrically a magnetic switch operates just like any other switch. A reed only switch needs to be protected against inductive or capacitive loads. To minimize the need for additional load protection, MagneLink Inc. offers semiconductor devices packaged with the reed switch. A triac for AC or transistor for DC voltage allows use with higher loads. The switch operates just as if it were a reed only device. However, the load on the reed is only the semiconductor. The functional load is switched by the semiconductor thus isolating the reed and providing much longer life. For a linear motion such as a printing press, MagneLink Inc. uses a unique reed arrangement. Three offset reeds in parallel provide a minimum of six inches continuous "on" at a magnet distance of 1/2 inch. This allows ample time for a press, or other device to slow down, and stop before reversing direction.