Help, please?

absf

Joined Dec 29, 2010
1,968
Think about this. When you add 2 single digit decimal numbers example 8 and 7. Are you able to get a single-digit decimal number sum? You will get 8+7=15. The digit "1" on the left is normally called "carry".

It is the same with binary. Adding 2 bit binary numbers would also yield a 3 bit answer. The Most significant bit (3rd bit) is usually called the "carry" bit.

If you google for the word "binary adder", you'll find there are half adders and full adders. Try to study them and read what they are.

Allen
 

Thread Starter

brahms

Joined May 9, 2014
32
I was trying to figure it out, because that was the idea that was given to me. I will try to make a 2 - bit adder, using transistors as the logic gates. Okay, i will do some research and try to find good explanations for adding binary numbers. But the real problem after these is making the circuit.. combining two logic gates circuits just by using transistor is too much for my level. :( But either way, got no choice. I'll do my best
 
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absf

Joined Dec 29, 2010
1,968



This is a NAND gate, i think. Is this correct?
The quad input NAND you drew will not work, The green LED doesn't have a current limiter in series.

And only the bottom most of the 4 input transistors will conduct when there is a "H" on its input.

Here is the 3-input NAND gate I simulated from the 7410 datasheet and it would work using 5V supply. This is for your reference.

Allen
 

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Thread Starter

brahms

Joined May 9, 2014
32
The picture, i got that from the net. So sorry I forgot to give the source because it was directly given. Thank you for the schematic, i will watch later some videos on full adder and half adder binary. Please guide me on making these project. Hehehe, thank you sir! :)

May I also ask what Application do you use for simulation?

Questions about the circuit:
I tried it, but i can't seem to figure it out. If I were to use a SPST switch to replace the inputs, where will i connect it? And also LED as an output, what will be the connection? I'm sorry, i'm new to these kinds of circuits..
 
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