An electric strike is an access control device used for doors. It replaces the fixed strike faceplate often used with a latchbar (also known as a keeper). Like a fixed strike, it normally presents a ramped surface to the locking latch allowing the door to close and latch just like a fixed strike would. However, an electric strike's ramped surface can, upon command, pivot out of the way of the latch allowing the door to be pushed open (from the outside) without the latch being retracted (that is, without any operation of the knob) or while excited the knob or lever can be turned to allow egress from the secured area.
Electric strikes generally come in two basic configurations:
Electric strikes are sometimes equipped with buzzers which allow someone outside the door to hear when the door is open. The buzzing noise is typically simply a result of applying AC current to the strike instead of DC, keep in mind the "buzzing" varies depending on voltage, and the coil or solenoid, although the buzzing from the AC current is audible, it is not designed to be loud for everyone to 'hear'. Using DC voltage, one would have to install an actual buzzer if they would want to "hear" the unit.
There are many manufacturers of strikes, and there are many things that have to be considered when buying one, i.e. type of jamb, type of locking hardware, whether one requires fail secure or fail safe, length of latch, depth of jamb, voltage requirements and the length of the faceplate. In some cases it is better to go with a magnetic lock
Before using a magnetic lock, the Fire Marshal or appropriate “Authority Having Jurisdiction” should be consulted. There are emergency egress issues that must be addressed before using a magnetic lock.