2 Channel Smart Dual Coil Latching Relay Board – 2 Channel Bistable Relay Module

This is a Smart Dual Coil Latching Relay that can control the ON/OFF power of a device by applying a short voltage pulse to Input 1 and Input 2. This project is helpful in low-power applications since the coil is not powered all the time, it only requires a short voltage pulse. Relay Coil also remains in that position even if the power is disconnected. Polarized, bi-stable, latching relays are utilized in many kinds of electronic equipment and diverse applications. These relays usually employ two coils, one to move the relay contacts(s) from the open to close position and another coil to move the contacts(s) from the close to the open position.  to facilitate mechanical movement, the relay coils need to be energized for a specific time interval. Once the contact(s) have changed position, the voltage should be removed from the winding of the relay. As shown in the schematic, a dual-coil relay is connected to its supply rail at the center point of the two relay windings Each winding can be energized by applying a TTL-short pulse to input A1, A2, B1, and B2. Diode D6, D7, D8, and D9 are used as clamping diodes. Operation is very simple, apply a minimum 150mS-500mS trigger voltage to input A1/B1, this will energize relay coil -1 and the coil moves contact(s) open to close, and when the pulse applies to input A2/B2, coil-2 energized and moves the contact(s) from close to open. All inputs can be triggered using push switches, Arduino/microcontroller and other circuits, applying 150mS to 500mS TTL pulse will energize the coil.