In this NAND Gate circuit I have used three Transistors. In this Project NAND gate is made by combining AND and NOT Gate. Here first two transistor in series is used for making AND gate and the last transistor which is parallel with LED makes NOT Gate. Both is connected by a 10K resistance. Output data of NOT gate is fed to a LED for indication.
a) Transistor = BC548 or any general purpose NPN Transistor will work.
b) LED (Light Emitting Diode) any Color except white.
c) Resistance = 10K-2Pcs, 270k, 1K and 220 ohms.
d) Slide switch or SPST Switch
e) battery container for connecting 2 cell.
This circuit works well and consumes only 3 Volt.
There is no power switch in the circuit so battery should be removed when not in use.
Circuit Diagram of NAND GATE is given below:-
Other logic gate such as NOT, AND, OR can also be created by NAND Gates. So people use NAND as Universal gate. This is also true for NOR gates.