I know that computers use binary to calculate instructions and perform tasks. But essentially no one I know can convert binary to decimal. I am working on a calculator project currently, and the problem I have is converting binary to decimal for display and utilitarianism. But all of the converting circuits I have seen have converted it into hexadecimal instead, and no one knows how to read hex either. How can I convert binary to decimal and vice versa?
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7490 counter chip. – Andy aka Feb 26 '20 at 17:08
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1It's very easy to convert BCD to decimal. It's not very easy to convert binary to decimal. Can you make your calculator work in BCD? – Transistor Feb 26 '20 at 17:09
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I don't have a 7490 chip at hand and I want to make it SSI or transistor calculator. And whats the difference between BCD and binary anyway? – Trevor Mershon Feb 26 '20 at 17:12
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Are you allowed to use integrated circuits? Transistors? Vacuum tubes? Rotors? Relays? – Harper - Reinstate Monica Feb 26 '20 at 17:15
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Well I only have transistors and logic gate ICs but I did do some research and I think I can make a calculator off BCD. – Trevor Mershon Feb 26 '20 at 17:16
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This was asked just 2 days ago https://electronics.stackexchange.com/questions/482932/3a9a767f-is-a-32-bit-hexadecimal-number-how-to-convert-it-into-decimal-number#comment1227606_482932 – Feb 26 '20 at 17:18
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1@TrevorMershon you asked "*How can I convert binary to decimal*" and you didn't stipulate that you were restricted on what you have in your store cupboard nor did you imply an inability to purchase these things or have some undisclosed deadline on ordering stuff. – Andy aka Feb 26 '20 at 17:20
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Try looking up Reverse Polish Calculator and build that in Japanese radio style using Chinese Transistors after you simulate in LogicSim. ;) – Tony Stewart EE75 Feb 26 '20 at 21:34
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Yes, it is possible.
If your input is straight binary (not BCD) and all you have is transistors and logic gates then you will need to start by creating the truth tables for the function you need. The inputs to the truth tables will be the bits of the binary value; the outputs will be the bits of the decimal value.
Once you have the truth tables you can try to use Karnaugh maps or Quine-McCluskey techniques for minimization.
Another alternative would be to use your transistors to build a ROM that did the conversion. The address lines to the ROM would be your binary bits and the data lines coming out would be the desired decimal bits.
Either way, you should probably sharpen your wirestrippers first.

Elliot Alderson
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What would be the point of making an entire ROM to do one calculation? That seems excessive. – Trevor Mershon Feb 27 '20 at 15:13
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The **point** is that it fulfills your stated requirements of making something with just transistors and gates. The **point** is that it doesn't require massive Karnaugh maps. – Elliot Alderson Feb 27 '20 at 15:16