Household combination lock circuit

To prevent theft, many homes can install combination locks .
Only your own people know it, so it's easier to open the door. But for
people who don't know the password. Then the door cannot be opened, which ensures safety.
    Figure 1-51 shows a double password electric lock circuit. YA in the circuit is the electromagnet that
controls the latch or door latch . Buttons SB1-SB10 are installed outside the door. Kl and K2 are intermediate relays , and AC 220V intermediate relays can be used as relays Kl and K2 .     (1) Open the door if your family members know the password. When opening the door, press the buttons SBI, SB2, SB3 and Sm to energize the solenoid and the door can be opened.     (2) Unable to open the door without knowing the password. If someone does not know the password while trying to open the town. If any one of the buttons SB8-SB10 is mistakenly connected , the relay Kl will operate, the normally closed contact of Kl will be disconnected, the electromagnet coil circuit will be cut off, and the bell will sound an alarm. In this case , even if the buttons SB1, SB2, SB3, and SB4 are pressed again according to the password requirements, the electromagnet will not move. Then if you want to unlock again, you must de-energize the Kl coil, that is, press buttons SB5 and SB6 at the same time. , SB7 resets the relay, and the normally closed contact of Kl closes;. Then the lock can be unlocked with the password. By changing the wiring position of buttons SB1~SB10, the combination of passwords can be changed. The double password electric lock is a double password electric lock circuit. YA in the circuit is the electromagnet that controls the latch or door latch . Buttons SBl ~.SB10 are installed outside the door. Kl and K2 are intermediate relays. Relays Kl and K2 can be optional AC 220V intermediate relays.