Introduction: Logic Gates Using Transistors and Diodes

About: "Guitar, Gadgets, Gravity My Three G(uru)'s in Life." I'm a high school senior who's passionate about science (and applying concepts to build new things). I run a YouTube Channel called 'Scientify I…

Hi, welcome to a purely circuits-based Instructable by Scientify Inc.!

Our aim today:

  1. To build various logic gates and study their working and truth table.
  2. To interlink various logic gates in combinational circuits.

A little introduction to logic gates...

Logic gates are the building blocks of every electronic circuit. One can be idealized or physical, and implements a Boolean function: it performs logical operations on one or more binary inputs and produces a single binary output. Binary input: 0 or 1, high or low They are primarily implemented using transistors or diodes acting as electronic switches.


  1. Breadboard
  2. Jumper Wires
  3. Transistors - BC547
  4. Diodes
  5. Resistors (100, 1k ohm)
  6. LED's
  7. 9V battery

It's good to have extras of some of these components like LED's as you may end up fusing them.

Step 1: Circuit Diagrams

To interconnect logic gates, take the output of one gate to the input of the other gate.

Step 2: Result

Pictures of our 2 setups are attached:

  1. 2 AND gates interfaced with an OR gate
  2. 1 NAND gate

Thank you for checking out the project! Please follow me for more such interesting projects. I think you'll find this project particularly delightful: a rover operated by intuitive hand gestures. Do check out my YouTube channel if you love science!

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