# Help using solid state relay with Arduino G3VM-21AR

Hello, I am trying to use relay G3VM-21AR with Arduino, but cannot get it working. Attached is my schematic.
When pin 2 is connected to Arduino Nano Every digital output pin, and output is high, I can measure about 4.8V there, but measuring pin 3 and 4 there is no connection between (and the load motor not running)
Pin 1 is grounded via resistor, according to the datasheet the trigger value should be between 0.7mA and 3mA,so
I have used resistor values between 1.6Kohm and 7Kohm with no success.
What am I doing wrong here ?
If this relay is not compatible to use with Arduino, can anyone recommend a suitable relay that works !
The relay should be small, max load <3A
Thanks !

relay_schematic.pdf (3.84 KB)

Reverse the connections to the IC's (G3VM) pins 1, 2.

Please note the datasheet shows the correct polarity of pins. To turn on the opto led you must forward bias it as shown. Use 750 Ohm resistor to aim for about 5 mA, forward voltage approximately 1.3V.

runaway_pancake:
Reverse the connections to the IC's (G3VM) pins 1, 2.

I have tried also reversing pins 1 and 2 with no help. The datasheet is not clear (or I cannot read it since I am not electric engineer). Which pin really goes ground ? According to this, pin 2 is gnd ??

Could anybody draw the correct schematic, does it matter whether the resistor is in pin 1 or 2 ?
What is the correct value of R. I have also tried 300 ohm, no help ?
With multimeter the current in this circuit is 0mA in all cases.

Please note the datasheet shows the correct polarity of pins. To turn on the opto led you must forward bias it as shown. Use 750 Ohm resistor to aim for about 5 mA, forward voltage approximately 1.3V.

So pin 1 goes to Arduino, resistor with pin 2 is 750 Ohm ?
What is the value of RL ? How do I connect the load ? For example motor (- to GND, + Vout and high voltage,12V to Vdd ?

It's NOT an opto-isol (as depicted in OP's PDF)

Here's a pic from the first page

Any Questions?

MANY thanks to "runaway_pancake " !
This circuit is finally working and the first clear schematic of this subject I see in the net.
I will continue testing and designing my schematics tomorrow.

Happy new year 2021 !