Full Adder in LTspice using Diodes and single Transistor

[Omkar Shinde]

I am trying to implement a Full Adder in LTspice using Diodes and single Transistor however i am unable to achieve the desired output. Please refer to the below screenshots. I am unable to add relevant asc file for refernce as the extension isnt supported here

The below article is used as reference.

https://www.instructables.com/One-T...cally a full adder is,full adder can reach 18.

 

[stenzer]

Hi,

you are using three input voltage sources (A, B & C) with ahigh value of 1 V.

Where are the nodes V(n001), V(n002) and V(n006) in your circuitry?

BR

--- Updated Oct 8, 2020 ---

unable to achieve the desired output.

How should your "desired "output look like? Your used LED has a quite high forward voltage. Thus you can not expect the same results as described in the provided link.

 

[Omkar Shinde]

Hi,

you are using three input voltage sources (A, B & C) with ahigh value of 1 V.

Where are the nodes V(n001), V(n002) and V(n006) in your circuitry?

BR

--- Updated Oct 8, 2020 ---

How should your "desired "output look like? Your used LED has a quite high forward voltage. Thus you can not expect the same results as described in the provided link.

i have attached the desired output image

 

[Omkar Shinde]

Hi,

you are using three input voltage sources (A, B & C) with ahigh value of 1 V.

Where are the nodes V(n001), V(n002) and V(n006) in your circuitry?

BR

--- Updated Oct 8, 2020 ---

How should your "desired "output look like? Your used LED has a quite high forward voltage. Thus you can not expect the same results as described in the provided link.

the nodes V(n001), V(n002) and V(n006) are my input carry nodes. They are located just before the three 10k resistors. N of diode is almost double the V forward which is true in most LEDs i checked online

 

[Omkar Shinde]

Referring to a new article i have created this new full adder using diodes and resistors now

Diode Full Adder | Details | Hackaday.io

<p>Of course, if you can do anything with the two-level diode sum-of-products formulation, you can do anything. Here's a shot at a full adder:</p><p><img data-src="https://cdn.hackaday.io/images/2045321486486357459.png" class="lazy"></p><p>It requires inverted and true inputs for A, B, and...

hackaday.io

how do i get output in this?

 

[FvM]

It's wrong to use 1 V input sources in post #1. Review the original article, they are using 5V input. I won't name the circuit an adder unless you have level comparators that convert the analog output voltage to defined logic levels. Is so far the full adder circuit is a kind of bluff package.

Post #5 circuit takes a different approach by using non-inverted together with inverted input signals. The adder core uses only diode logic, but it can't work without external inverters.

A fully featured adder can be cascaded without additional inverters or buffers. In so far neither of the presented circuits is a complete adder.