As I understand opto couplers, their main use is to isolate a circuit from another,mainly for protection purposes. In my case I have an Arduino which controls a couple of shift registers (74HC595) which trigger transistors and I would like to protect the Arduino and the Shift Registers from any damage.
Since the Arduino works with 5V, and the Transistors will be switching 12 - 14VDC, BOTH INPUT and OUTPUT will be using the same ground. My question is this.
Does it make sense to use an opto coupler since I will be using the same Ground? I mean is there any protection at all?Some more info on the power source:
The main power source is going to be a car battery OR an ac transformer converted to DC. For the Arduino I am going to get this voltage and stabilise it using a 7805.
Thanks a lot