[Alex KL-1]

Originally Posted by Alex KL-1

For a given generic relay, a example:...

Is needed to locate the C (common), NC (normally close) and NO (normally open) contacts. Some are described on the body of relay, sometimes below (then is needed to remove to check it). Sometimes not have any markings, but for sure, some contact is NC when the relay have 3 pins for each contact. Some relays have only 2 pins for contacts, and have only NO or NC contacts.

2 pins absolutely are for the coil. For example, is possible to drive it (with relay removed from PCB) with a 9V battery if is a 9 to 12V relay, for testing, and watching if the contacts switch between NC and NO. Open coil, of course, render it useless.

Then, a generic 2 contact relay with NO and NC contacts (an example for "stereo" audio commutation in equipment) will have 8 pins at least: 3 for one set contact (the C, NC and NO), 3 for another, and 2 for the coil.

Generally , the contact pins are grouped together, at opposed side of the coil contacts.