Why are there few 5v relays with a driving voltage below 5V

The relay is an electrical control device, which is an electrical appliance that causes the controlled quantity to undergo a predetermined step change in the electrical output circuit when the change in the input quantity meets the specified requirements. It has an interactive relationship between the control system and the controlled system. Usually used in automated control circuits, 5v relay is actually 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.

Drive voltage 5v relay is rarely because the lower the voltage, the worse the performance of the relay, especially the slower the contact and separation speed of the contacts, which is the most critical performance of the relay. In order to ensure that the contacts have sufficient contact pressure when the voltage is low, it is necessary to increase the current, which puts a burden on the control board.

The 5v relay and below are all used in electronic circuits. It is a bit dangerous to use 5v with such a large current. The voltage is still low, the current demand is high, the suction force is not enough, and it is not commonly used.

5v relay drive circuit application

The high-level drive capability of the output pin of the single-chip microcomputer is weak; when it is at the high level, the drive capability is weak and cannot output enough current to drive the 5v relay. At low level, the drive capability is stronger and can absorb a larger current.

If the 5v relay drive current is small, consider using the IO port of the single-chip microcomputer to directly drive it with a low level. If necessary, use two or more IO ports to drive in parallel.