6Pcs DC 3.3V Relay Module 1 Channel Optocoupler Module 3V/3.3V Relay Isolated Dr About this item 1 channel 3V/3.3V power relay module support photocoupler isolation control; The external connection adopts rotary crimping terminal to make the connection more firm. The module can used to control 10A 250V AC, 10A 30V DC load, with output signal indicator. Adopt dual power supply selection design to enhance anti-interference ability. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit. The signal input port can be connected to the single-chip IO port, driven by high-level signals. You are free to select whether the relay and the signal share the same power supply or not by removing the jumper caps on the pins or not. It is recommended to share the same power supply, because that is more convenient for using. The relay isolation drive control module, the core is an electronic control device relay, with a control system (also known as an input loop) and a controlled system (also known as an output loop), which is essentially a "automatic switch that uses a smaller current to control a larger current" ".