Introduction: Build a NAND Gate From Transistors

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About: “Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla

Here I am going to show you how to build a NAND gate from NPN transistors.

If you would like to get a better idea of how I am using the transistors, visit my other guide onbuilding a AND gate.


Step 1: Parts List

You are going to need the following parts to build the NAND gate:

  • 1x Breadboard
  • 1x LED (Any color)
  • 1x 1K Ohm resistor
  • 2x 10K Ohm resistors
  • 2x NPN Transistors (I used the 2N2222)
  • 2x N.O. Push buttons
  • 5x Various length wires/Jumper wires

You also need to know how to build a circuit from a schematic.

Step 2: Schematic / Truth Table

To build the NAND gate, just follow the schematic from the above image. The truth table is also shown, if your build doesn't match the states listed in there then you have done something wrong :( .

The NAND gate is actually somewhat special in that its also referred to as a universal logic gate, being that it can be used in combinations to make all the other gates (AND, OR, NOR, XOR, XNOR,) just by itself. I have (poorly) drawn three combinations of NAND gates to simulate a OR, AND, and inverter.