Four Reasons to Replace a Reed Switch with an MR Sensor in Appliances
As sensor manufacturers continue to advance MR sensor technologies, designers will have one more sensor technology in their arsenal.
Design engineers have used reed switches in low-power, battery-operated applications for four key reasons. The mechanical reed switch offers “zero” power consumption, high sensitivity, and low cost. In addition, there has not been a suitable alternative technology. These advantages are not entirely true anymore thanks to new magnetoresistive (MR) sensing IC options that can provide position sensing with virtually no power consumption, high sensitivity, and high reliability and durability, while housed in a small package.
Before the development of solid-state sensors, magnetically-activated reed switches, which have been around for decades, provided a proven and inexpensive solution for position sensing. The reed switch consists of two ferromagnetic leads that are hermetically sealed in a glass capsule or tube. When a magnet comes in range of the switch, i.e., a magnetic field is applied to the leads, the contacts close creating a switching function.