5v relay is generally used in electrical control circuits to amplify the contact capacity of miniature or small relays to drive larger loads. For example, the contact of the relay can be used to connect or disconnect the coil of the contactor. Generally, relays have more open and close contacts. Of course, relays can also achieve some special functions, such as logic operations, through proper connection.

The contactor is used to connect or disconnect the load with higher power. It is used in the (power) main circuit. The main contact may have interlocking contacts to indicate the opening and closing status of the main contact.

The contactor uses a coil to flow current to generate a magnetic field to close the contact to reach the electrical appliance that controls the load. The contactor is composed of electromagnetic system (iron core, static iron core, electromagnetic coil) contact system (normally open contact and normally closed contact) and arc extinguishing device. The principle is that when the electromagnetic coil of the contactor is energized, it will generate a strong magnetic field, which makes the static iron core produce electromagnetic attraction to attract the armature and drive the contact action: the normally closed contact is disconnected; the normally open contact is closed, the two are Linkage. When the coil is de-energized, the electromagnetic attraction force disappears, and the armature is released under the action of the release spring to restore the contacts: the normally closed contact is closed; the normally open contact is disconnected.

The essential difference between a 5v relay and a contactor is that the load is different. The contactor with the larger current capacity is the contactor, and the smaller is the relay. There are also differences between the contactor used in the main circuit and the relay used in the control circuit.

The function of the contactor is to switch on and break larger current signals, and to drive power equipment such as motors; the function of 5v relay is to convert signals, control signal interfaces between devices of different voltage levels, and its contacts The carrying capacity is generally small, used to drive electrical components such as contactors.