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 ...

A very simple but highly efficient combination lock circuit is shown in the figure. Any type of on/off switches can be used, varying from commercially available inexpensive types to more sophisticated ...

Here is a great collection of touch switch circuits. A touch switch is an electronic device that enables us to control a circuit by simply touching a sensor. Simple touch switch circuit with 4011 – ...