This simple code lock circuit described here is of an electronic combination lock for daily use. It responds only to the roght sequence of four digits that are keyed in remotely. If a wrong key is ...

The main principle of this circuit is that the door lock opens only when the buttons in series are pressed at a time. We can use it to lock the doors and for other security purposes. This article ...

The system is fully controlled by the 8 bit microcontroller 16F877A which has a 8Kbytes of ROM for the program memory. The password is stored in the EPROM so that we can change it at any time. The ...

Logic gates, simplification of Boolean functions, design and testing of combinational and sequential circuits including code converters, multiplexers, adders, and synchronous counters. For ...