what is a form "C" relay?

[pjwinstalls]

looking at the system sentrol smokes and the elk m1 and they both say they have form "c" relay. What is this for?

Thanks

Philip

 

[WayneW]

http://wiki.answers.com/Q/What_would_a_1_F...Form_B_relay_be

Form C relays are SPDT and break the connection with one throw before making contact with the other (break-before-make).