Hi - so somebody drew up this circuit for me a year or so back, and all of it seems very basic and easy to understand, except for the diode. What is teh purpose of the diode in this circuit? It works fine both with and without the diode attached, so I'm thinking it must be protection against something - but I'm not sure what. Here's the circuit:
If k1 is an inductor or any sort of componant which will store charge, when the circuit is deactivated k1 will produce back EMF and a VERY large voltage the diode prevents this back EMF from killing any componants. At least im fairly sure thats what it is.
The diode is attached to the coil on the relay. After you power up the coil, shutting it down causes a reverse current, which the diode can sink without causing harm to the other components.
