I was wondering how this 5V relay module works exactly.
I understand how the actual relay circuit (SRD-05VDC-SL-C) works but I'm not totally sure how the signal and 5V inputs work.
My guess would be that the 5V is somehow dropped down to, lets say 4V, and then is combined with the signal voltage (let's say 3.3V from a 3.3V pin from an Arduino.) If the signal input is HIGH then the relay (SRD-05VDC-SL-C) receives a voltage greater than 5V and closes, but if the signal input is LOW then the relay is receiving just the 4V from the VCC and stays open.
If that is the case, how does the relay module do this using diodes, resistors, etc.
If that isn't the case then does anyone know how this thing works?