Switching devices or contacts are widelyare used in various electrical or radio engineering devices. To improve the operational properties of the equipment, to extend the service life and improve the reliability of joints use special sealed magnetically controlled contacts, which are called reed switches.
The devices consist of a core,made of soft magnetic material, to which contacts are connected through insulating gaskets. When a current flows through the coil, a magnetic field appears in the core, which acts on the contacts and causes them to close. After stopping the supply of electric current through the coil, the contacts are opened.
Despite the use of various devices,Today the reed relay in many cases remains out of the competition due to the ease of use, the properties of dry contact, galvanic isolation from batteries. It is still used in a variety of devices and circuits.
The reed switch is simply irreplaceable, if it is necessary to ensure the durability and high reliability of switching elements.
According to the functional features of the reed switchare divided into switching, closing and opening. According to the design technological parameters of the device are divided into two categories: with mercury and dry contacts. The latter variety is practically no different from ordinary contacts. Mercury elements have a drop of mercury inside the glass hermetic housing. This is necessary for wetting contacts during operation, which allows to improve the quality of the connection by reducing the adapter connection, and also helps to get rid of the rattling of the contacts.
Reed switch generates vibration or bounce whenclosing or opening contacts. This results in a single actuation to multiple signal switching and a significant increase in the response time. When such devices work in digital microcircuits, measures are taken to suppress side effects using triggers or RC-chains.
Any reed switches in their design are represented inA glass bottle in the middle of which there are contacts. These elements are made like magnetic cores, which are welded around the ends in a balloon. The outer ends of the core are required to connect the device to the external electrical circuit.
The most widespreadsensors whose contact group is working on a short circuit. In such devices, each contact is made of an elastic ferromagnetic wire, flattened to a rectangular shape. To reduce the transition resistance and to improve corrosion resistance, the contact surfaces are covered with gold, rhodium, palladium or silver and their alloys.</ p>