Simple and practical solution for keeping a strike open for a given time.
Period: 0.25-1023 sec. 12V AC/DC.

By pressing the push button, the time relay will be activated. Accordingly, the door becomes openable for the set time. During this time the door can be opened. When the door closes, the lock will be locked immediately.

With AC operation unlocking the strike makes a humming tone (use a transformator as a power supply). With DC operation there is no tone (use a rectifier as a power supply).