5v relay products, a kind of switch electrical appliances, are used very much in control circuits.

5v relay products are composed of four parts, namely coil, magnetic circuit, reaction spring and contact. The purpose of the coil is to generate electromagnetic attraction when it is energized, which drives the armature of the magnetic circuit to attract and make the contacts produce displacement actions. The magnetic circuit consists of an iron core, an iron choke and an armature. Its task is to establish a magnetic path for the magnetic flux generated by the coil.

In the magnetic circuit, the most important thing is the magnetic circuit air gap, which is a gap between the armature and the iron core. When the coil is not energized, the air gap is the maximum value, and the contact is in the initial state; after the coil is energized, the air gap is zero, and the contact is displaced into the action state. The function of the reaction spring is to provide the armature with a repulsive force opposite to the direction of action. When the coil is de-energized, it can help the armature and contacts to reset. The contact is used for external execution control output, and it is composed of a normally closed contact and a normally open contact.

After the coil is energized, the normally closed contact opens and the normally open contact closes. After the coil is de-energized, the normally closed contact and the normally open contact are reset to the initial state. There are three types of relays, namely voltage relays, current relays and intermediate relays. Voltage relays have multiple coil turns and thin wire diameters, and the coil is connected in parallel with the load. Voltage relays are the main types of our common relays. The current relay has a small number of turns and a thick wire diameter. The coil is connected in series with the load, so its working current is the load current.