An electric strike is a device that's installed on a door to allow access with an access control system or some other type of remote release system. The electric strike, unlike a magnetic lock doesn't actually secure the door. A door with an electric strike is being secured by the lockset or door handle. What the electric strike does is allow access to a secured door without the need for a key to unlock the lockset.
If you look at a normal door, you'll see three major parts that keep it secure. The first part is the lockset. The lockset consists of several parts but the 2 major parts are the handle and the latch. The handle is the part that you use to open a door. The latch is the piece that sticks out the side of the door. This is the piece that actually keeps the door locked and retracts whenever the handle is turned. The third part is the strike (or strike plate or door strike). What the strike does is provide an hole for the latch to rest in.
The strike looks like a metal plate with a hole in it. When the latch falls inside of the hole, it keeps the door from opening. What the electric strike does is replace this strike plate. When the electric strike is used, the side of the strike is cut out and has a hinged piece of metal. The piece of metal swings whenever the release system is activated. This allows you to open the door without unlocking the handle. So basically the electric strike has the same hole as the strike plate except that the electric strike hinges on the side to allow the latch to move out and allow the door to open.
There are several advantages to using electric strikes over other types of locks. However . . .
Not all doors can use door strikes. Some doors that do not have locksets cannot use a electric door strike since a lockset is required.
Locksets may need to be replaced to use a electric door strike. There are many different types of locksets with many different functions. The correct function for an electric strike would be one that stays locked from the outside (can be momentarily unlocked with a key but not permanently) and has no type of lock/unlock button on the inside. This function is called a "store room function". Other types such as locks that have a lock/unlock button on the inside would defeat the purpose of the strike.
Permanent damage is done to door frame. In order to install a door strike, part of the door frame must be cut out. This is not a problem unless you want to move the strike to another door. That would leave a large hole in the strike. Some manufacturers sell filler plates to cover up the hole but most of the time, the strike would just be left in the door and another would be purchased for another door.
Can be affected by air pressure. Inside of an electric strike are several moving parts and if the latch of the door pushes on the hinged plate of the door strike causing a binding effect, the electric strike will not unlock. You can tell when this happens whenever the access system is activated but the electric strike will not unlock unless you pull on the door. Essentially you are taking the pressure off of the strike allowing it to unlock. This pressure is caused in some buildings by the pressure from the air conditioning system. If you feel the air rush out with the door partially opened, that same air will be pushing out on the door causing the strike to bind.
So should you use an electric strike for your access control system? Well, it all depends. There are many different types of electronic locks and each lock has it's advantages and disadvantages. If you've got a high profile door; one where appearance is very important; you may want to skip a maglock and go with a electric strike or maybe an electrified mortise lock. If you want a higher security door; one where an access card and not a key can open... a magnetic lock may be the ticket.