I am trying to hook up a train horn on my truck and I want to open a valve with a switch. I have a solenoid actuated valve that is 12V 400mA. Can I connect it directly to a switch from the battery, or will I need a relay or something else so I don't burn it out?
Best Answer
A relay will make the same physical contact that a switch will. Most automotive switches could handle 400mA easily. Relays become important when the amperage being handled is greater, as when headlights are being used.
You could use a relay in a standard configuration with a switch if you want.