Time relay (time relay) is refers when added (or removed) input operation signal, the output circuit and subject to the provisions of the exact time to produce jump changes (or contact action) is a relay. It is used on a lower voltage or a small current circuits, for turning on or off the high voltage, high current electrical components of the circuit. Meanwhile, the time relay is also a principle of using electromagnetic or mechanical delay control principle to achieve control appliances. Many of its kind, with air damping, electric and electronic type.