Dry reed relay is composed of reed switch (dry reed switch tube) and durable magnet or stirring coil. It consists of two magnetic and conductive reeds sealed in parallel in a glass tube filled with lazy gas to form a switch element.

 Working principle: Suppose a durable magnet is placed near reed switch, maybe a coil is wound outside reed switch and current is applied, then two reeds will be magnetized under the effect of magnetic field. Because the adjacent ends of the two reeds are different in magnetism and attract each other, when the reeds touch each other, the controlled circuit will be switched on: take the durable magnet away, or block the current flowing into the coil. At this moment, because the magnetic field is missing, the reeds are separated from the touch by their own elasticity, and the controlled circuit will be switched off. The size of reed switch can be divided into micro, small and large. The micro only needs the size of rice grains, and the large one is similar to a pencil.

 The stirring coil of the reed relay can be sleeved outside the reed switch, and the magnetic field in the coil is used to drive the reed switch. It can also be placed around the reed switch, using the external magnetic field of the coil to drive the reed switch (the coil base can be placed into the iron core to enhance the driving force).

 This relay is characterized by: (1) the contact is isolated from the atmosphere, and the tube is filled with lazy gas, thus avoiding the corrosion of external organic steam and contact, and greatly reducing the oxidation or carbonization of contact caused by burning flowers; (2) The reed is light and short, and its natural frequency is high. The on-off action time of the contact is usually only 1 ~ 3 ms, which is 3 ~ 10 times faster than the usual electromagnetic relay. (3) Small volume and light weight; (4) The defect is that the switch capacity is small, the contact resistance is large, and the tremors occur briefly.

 In addition to forming a reed relay with a coil, the reed switch can also be conveniently used in cooperation with a durable magnet. The durable magnet can approach reed switch from arbitrary direction to make it move, so I wont repeat it here.