FYI I posted an article on Ladder Logic. Looking for some feedback.
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Before we go any further, let me just explain a relay (just in case) - A relay is an electromechanical switch. It has a set of contacts, light your typical household light switch, PLUS a solenoid-type mechanism that operates the switch. So you house lights are switched by your hand, and a relay is switched by sending current through it's coil. There are a zillion types of relays, but this tutorial focuses mainly on the general purpose type, which have one coil, and at least one set of contactcs (common, normally open, normally closed).
Connecting to 0v will not do anything for the back EMF from a coil, what is needed is a diode to dissipate the back EMF. Exactly as you have explained towards the end of the article.In Ladder diagrams, RELAY COILS ALWAYS GO ON THE RIGHT, CONNECTED TO 0V OR NEUTRAL. Putting switches between a coil and ground violates convention, and is not a good idea to do it in real life because as the EM field in the relay coil collapses, it will arc across contacts. Placing the relay coil with one side terminated to outgoing power give the relay good place to dump this stored energy.
i am pretty sure you meant "like your typical..."A relay is an electromechanical switch. It has a set of contacts, light your typical household light switch
In Ladder diagrams, RELAY COILS ALWAYS GO ON THE RIGHT, CONNECTED TO 0V OR NEUTRAL. Putting switches between a coil and ground violates convention, and is not a good idea to do it in real life because as the EM field in the relay coil collapses, it will arc across contacts.