reedreläed

Reedreläed, also known as reed switches, are electromechanical devices used as simple switches. They consist of two ferromagnetic reeds sealed within a glass envelope. These reeds are typically made of a material like rhodium-plated iron or nickel-iron alloy. When a magnetic field of sufficient strength is brought near the reed switch, the reeds become magnetized. If the magnetic field is strong enough, the reeds attract each other and make electrical contact, closing the circuit. When the magnetic field is removed, the reeds lose their magnetism, and the spring action of the reeds causes them to separate, opening the circuit.

Reed switches are categorized into normally open (NO) and normally closed (NC) types, though the NO configuration is far more common. NO switches are open when no magnetic field is present and close when a magnetic field is applied. NC switches are closed without a magnetic field and open when one is applied. They can also be configured as changeover (SPDT) switches.

The advantages of reed switches include their sealed construction, which protects them from dust and moisture, leading to a long operational life and reliability. They operate in a vacuum or inert gas, preventing contact oxidation. They are also relatively inexpensive and can handle a variety of switching applications. However, their sensitivity to external magnetic fields can be a disadvantage, and they are generally suited for low-power applications due to limitations in current and voltage handling capabilities. They are widely used in applications such as sensors for position detection, alarm systems, and in simple electronic circuits.