I am using the Arduino to signal an optocoupler that is part of a PCB. In the board, the signal has to go through a 680 Ohm resistor before it gets to the optocoupler. The data sheet for the optocoupler I am using can be found here. http://optoelectronics.liteon.com/en-us/api/DwonloadFileHandler.ashx?txtSpecNo=DS-70-99-0019&txtPartNo=MOC3023
I cannot everything to work right. When I hook up a AC-DC regulator to the PCB, the optocoupler works fine. I am beginning to think the Arduino does not give enough voltage or current.