There are various types of relays including electromagnetic relays, electronic relays, non-latching relays, multi-dimensional relays and thermal relays classified based on the function, application type, configuration or structural features. Here is a brief about Latching Relays and Reed Relays which are more popularly used in various applications:
A latching relay maintains its state after being actuated. In the various type of applications, it is needed to limit power consumption and indulgence, for that kind of applications a latching relay is best suitable. A latching relay comprises strong internal magnets. Upon supply of the current is supplied to the coil, the magnet holds the contact position and requires no power to maintain position. Even after being actuated, they remove drive current to the coil cannot move the actual position. Thus, it saves a considerable amount of energy. Latching relays can be manufactured with one or two coils responsible for the position of the relay’s armature; thus, relays don’t have any default position. Latching relays are able to maintain their positions once they are actuated but resetting their position depends on the control circuitry.
Much like the electromechanical relays, reed relays produce the mechanical actuation of physical contacts to open or close the path of a circuit. However, compared to electromagnetic relays, reed relays contacts are much smaller and have low mass. Such relays are designed by coils wrapped around the reed switch. The switch acts as a shield, and it is a glass tube or capsule filled with an inert gas within which two overlapping reeds are hermetically sealed. The overlapping ends of a reed relays consist of contacts to connect input and output terminals. With the power being supplied to the coils, a magnetic field is produced. These magnetic fields cause reeds to be drawn together, making a closed path through their contacts. Also, during the coil’s de-energizing process, reed relays separate apart by a pulling force of spring attached to it. A reed relay’s switching speed is ten times faster than an electromechanical relay due to the less massive, differently actuating medium and smaller contacts. However, these relays also suffer from electrical arcing due to smaller contacts. If there is an event of switching arc jumps across the contacts, this may lead to welding of contacts if both contacts are closed.