Many of our followers would like to learn more about an Endurance MO1 PCB.
I would like to tell you the best way you can modify it.
As you can see the working current for the optocoupler PC817 is in range 10-50 mA.
In our MO1 PCB we have a resistor for 680 ohm
according to the Ohm law 3.3V / 680 ohm, we have less than 10 mA.
It means that the MO1 PCB will not work if the voltage is less than 3.3V
So if you want to run an Endurance MO1 PCB in 2-5V range you need a resistor of 120 ohn and it means that a current will be 16-44mA.
Also, there is another parameter that is important – it is a value of a reverse voltage. It is 6V. So if you miss polarity of the TTL with more than 6V value then the optocoupler can be damaged.