Quote Originally Posted by Nr1madman View Post

The way I think of a circuit is if it's open, then the current is free to run through. If it's closed its a broken component or disconnected switch or something :)

As I said, language difficulties!

Cheers
What you say makes perfect sense - if you are thinking about a tap or valve controlling water! Tap closed - no flow. Tap open - flow. However, when you are talking about electrical contacts, you have to imagine the contacts themselves. "Closed" means the contacts are touching, so current flows. "Open" means that there is a gap between them so no current flows. When you hear open or closed referring to switches, visualise the contacts themselves and it might help. Same principle applies even when it's an electronic switch like a proximity switch - closed and current flows, open and current can't flow. Then, "normally closed" means that current will flow until the switch is operated. Same for a relay.

Good luck!