DTL logic family


For me, the first examination at the university for this year will be “Logic Networks”. My electronics-deviance how could resist to implement a logic gate family from scratch? Here it is, Diode Transistor Logic the flint-stones way! DiTieL let’s go!!!

I’ve decided to use only commonly available components:

  • 2N2222 NPN
  • 1N4148 diodes
  • 1kOhm resistors
  • 10kOhm resistors



NOT, AND, OR combined together could make any kind of combinatorial logic circuits as example I’ve tried to make an EX-OR.

This basic implementation works but have soma major drawback specifically on the port couplings, output driving stages.
I’ve soon found that the use of a complementary type NPN and PNP transistor solves this problems.

Part list changed:

  • BC547 NPN
  • BC557 PNP
  • 1N4148 diodes
  • 1kOhm resistors
  • 10kOhm resistors

Measures confirm that this implementation is better than single 2N2222 version as per power efficency