relay JD-VCC connection

Pic of relay module is attached below, it has only one GND

As i want to use a separate power supply of 5V, i connected separate supply's +Ve terminal to JD-Vcc and -Ve terminal to "GND-IN1-IN2-IN3-IN4-Vcc"'s GND of relay module.... and connected Arduino's 5V to "GND-IN1-IN2-IN3-IN4-Vcc"'s Vcc... does this connection make the relay optically isolated?????

Would be similar to this four relay board.


Try this, 5V of course: graphic by @dlloyd.

756E6C bro,
the module i'm using doesnt have 2 GNDs... only 1 GND... only 2 pin header (JD-Vcc, Vcc)..

From dlloyd


so u r telling me everything's ok with my connection???

tx larry

If you are wired as in post 4, you have opto isolation.


Larry's right: Post 4 in the right way. NO connection to Arduino GND..

Some more information about all this HERE

The circuit and the isolation barrier look like this:


I think that diagram should be modified to make things clear.
The two VCCs (opto and jumper) need to be connected, since they are on the board.
Then the isolation barrier needs to be re-drawn throught the jumper.

@Wawa, Good Idea! How is this??