TRONIX FUNDA

Op-amp virtual ground and virtual short concept  

Building Logic gates using Op-amp   1.AND gate using op-amp:circuit diagram Check out the above circuit At inverting input of opamp a reference voltage of 3.75 is given which is approximately 3/4th of Logic 1 i.e 5V So that it can operate well like AND logic.

Code lock system:Simple project     When you make on the buttons 1,3and 6 the lock will open the relay will be driven and you can drive your load whichever is connected to the relay circuit. Its implemented and tested in PROTEUS simulation software. Have a fun with this simple lock system.