Visit my github to access the files: marknarain/digital-full-adder: Full Adder in Digital Logic (github.com)
Overview
I started designing this digital full adder shortly after learning about logic gates. In the beginning I started by drawing a full adder using XOR-gates and and-gates. The next step was to replace all gates with NAND-gates, so I drew a full adder using 9 NAND-gates. After drawing the whole logic with NAND-gates, I designed the circuit using the circuit simulator of HTL Braunau. I have included KiCad files, files for the circuit simulator (link in requirements) and other pictures.
Module 1: Bipolar transistors:
I built the first module of the full adder using bipolar transistors.
You can find the CircuitSim, the KiCad files and pictures in the folder Transistors.
Materials:
- 19x BC547C: NPN General Purpose Amplifier
- 9x Resistor (10kΩ)
- 3x Resistor (330kΩ)
- 18x Resistor (100kΩ)
- 3x LED (5mm, red)
- 3x Sliding switch
- Copper wire
- Pin headers (angled, 2-row)
Module 2: NAND Gates (74HC 00)
The second module is made by using NAND-Gates. This module can be connected to module 1 or the power supply directly by using the pin headers.
Materials:
- 3x 74HC00: Quadruple 2-input NAND-gates
- 3x Resistor (330kΩ)
- 3x LED (5mm, red)
- 2x Sliding switch
- Pin headers (angled, 2-row)
Power supply
The power supply of this device consits of:
- 1x Battery holder
- 1x 9V Battery
- 2x Capacitor (100nF)
- 2x Capacitor (100µF)
- 1x Voltage regulator (-5V, MC7905)
- 2x Sliding switch
- Pin headers (angled, 2-row)
I didn’t have a positive voltage regulator (MC7805) at home, so I used the negative one (MC7905).
More modules to come…
- Full adder (74HCT283E)
- Raspberry Pi pico
- FPGA
- MOSFET transistors
- …
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