#845 DEMUX Gate with NAND Logic

Demonstrating how a DEMUX gate may constructed solely from NAND gates.

Notes

A demultiplexer performs the opposite function of a multiplexer: It takes a single input and channels it to one of two possible outputs according to a selector bit that specifies which output to choose.

The DEMUX Truth Table:

An DEMUX gate can be made with NAND gates as follows:

Circuit Design

Designed with Fritzing: see DEMUX.fzz.

The Sketch

See DEMUX.ino.

The sketch simply automates the Input, Select signals, cycling through all 4 possibilities.

Test Results

Here’s a scope trace capturing all 4 states, and demonstrating the the output is correct as expected. Traces are offset vertically for clarity.

• CH1 (yellow): Input
• CH2 (blue): Selector
• CH3 (red): Output A
• CH4 (green): Output B

Credits and References

• CD4011 datasheet
• https://en.wikipedia.org/wiki/NAND_logic
• See also:
  • LEAP#838 AND Gate with NAND Logic
  • LEAP#839 OR Gate with NAND Logic
  • LEAP#840 NOR Gate with NAND Logic
  • LEAP#841 NOT Gate with NAND Logic
  • LEAP#842 XOR Gate with NAND Logic
  • LEAP#843 XNOR Gate with NAND Logic
  • LEAP#844 MUX Gate with NAND Logic
  • LEAP#845 DEMUX Gate with NAND Logic