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 AND Gate & NOT Gate is connected by a 10K resistance. Output data of NOT gate is fed to a LED for indication.
Circuit Diagram of NAND Logic Gate
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 consumes only 3 Volt.
There is no power switch in the circuit so battery should be removed when not in use.
Other logic gate such as NOT, AND, OR can also be created by NAND Gates. In next experiment we will proof NAND as Universal Gate. This is also true for NOR gates.