Difference between NO and NC contacts
NO (Normally open) contacts: When the coil is not energized these contacts are open not allowing current to flow through these contacts and when the coil is energized these contacts are closed completing the circuit and allowing current to flow through these contacts.
NC (Normally close) contacts: When the coil is not energized these contacts are closed and complete the circuit and allow current to flow through these contacts and when the coil is energized these contacts are open and do not allow current to flow through these contacts.
