About Relay Contact Status

Relay is an electrical control device, is when the change of the input amount to meet the specified requirements, in the electrical output circuit to make the controlled amount predetermined step changes of an electrical appliance. It is essentially an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit. The contact of the relay is the soul of the operation of the relay. The contact of the relay is in the normally open or normally closed state, which is simply understood as the contact of the switch that is normally open or normally closed to make the signal on or off. It is called the contact of the relay.When it comes to relay contacts, many people will think of H, D, Z/A, B, C, NO, NC, SPDT, DPDT and other key words, so today, let's talk about what these words stand for.

First of all, about contact state H, D, Z, which is usually the expression of relay contact state in the Chinese market, H stands for "He" in Chinese, which means that the two contacts are disconnected when the coil is not energized, and then the two contacts are closed after energized. This is what we usually describe as the open state of the contact. D stands for "Duan" in Chinese, which means that the two contacts are closed when the coil is not energized, and they will be disconnected when the coil is energized. This is what we usually describe as the open state of the contact. And Z stands for "Zhuan" in Chinese, representing the transition type of contact state. For the international market, normally open, normally closed and transition contact states are usually expressed by A/B/C.

While NO and NC refer to the state of relay contacts in NORMAL (when not energized), NO is NORMAL OPEN, that is, normally in the state of not energized, is disconnected, energized under the action of the electromagnetic coil in a closed state. NC is NORMAL CLOSE, that is, usually is not energized state, is closed, energized under the action of the electromagnetic coil in a disconnected state.

And what is SPDT? SPDT is the abbreviation of Single Pole Double Throw, which can control the power output to two different directions, that is to say, it can be used to control two devices, or it can also control the same device for switching operation direction. DPDT refers to Double Pole Double Throw, which is actually made of two single-pole and double-throw switches side by side. Its wiring mode is exactly the same with each single-pole and double-throw switch. The two knives are connected through an insulating plastic, and then share a handle. Double pole double throw switch each side is equivalent to a single pole double throw switch, can do two single pole double throw switch use; Double pole double throw switch on the same side each two adjacent terminals equivalent to a single pole single throw switch, can be used for four single pole single throw switch.

We believe there is something you might like to add and learn about the relay contact status, and we sincerely hope you can let us know in the comments section. For more information about the relay, you can also check out our website: www.ivy-metering.com