# COMMUNITY : FORUMS : TECH

## diode logic

I'm making a giant adding machine using only resistors(miscellaneous), switches SPST (for input) LEDs (for display) and diodes(for logic). NO TRANSISTORS I have it so that it can recognize 0,1,2,3,4,5,6,7,8,9, but if it recognizes 8, then it recognizes it as all the other numbers. If it recognizes 0, it recognize 1, and 7. If it recognizes 6 it recognizes 1, and 5. If it recognize 9 it also recognize 7. If it recognizes 3, it also recognizes 7. basically if you take a 7 segment display, any number on it, it'll recognize all the numbers in the number. I need help sorting it ou so that if it recognizes 8, it only recognizes 8. If it recognizes 3, it only recognizes 3. Etc...

sort by: active | newest | oldest
 1-10 of 76 Next »
takide6 years ago
cool idea!
id hate to burst your bubble but you cant replace transistors with diodes, because transistors can do alot more then you would think they can.
6 years ago
Actually you CAN do this, if you don't mind it taking up a LOT of space. Before transistors, they used vacuum tube diodes just for this purpose.

The first semiconductor diodes, called cat's whisker diodes, developed around 1906, were made of mineral crystals such as galena.  See my instructable on simple Radio construction.

A lot depends on the breakdown voltage of the diodes one wishes to use.  In the right combonation one could use jfets, tunnel, zener, schottkey, mosfet, or TVS diodes to achieve the desired effect.   Here is where a bread board would shine, as one would have to fiddle with the combonations for a bit to get it to work flawlessly.
6 years ago
accept you cant use diodes to amplify or oscillate current.
6 years ago
Actually, you CAN use them to make oscillators. You just need the right kind of diode.

Steve
6 years ago
amplification is actually very obtainable too, as this is how small voltages are turned into higher voltages- with diodes.
.
Goodhart10 years ago
Not to divert from your subject, but I have been looking for a schematic of a simple diode circuit that uses, I believe, one or two Shottkey diodes or tunnel diodes or barrier diodes (my memory is fading I am afraid) and one LED to indicate leaks from a Microwave oven. I am at a total loss It was featured in the Nuts n Volts magazine many MANY moons ago.
10 years ago
sorry to ask/put it rudly but what is the relevance of that?
10 years ago
It isn't relevant (thus the apology straight off) :..-.( But I didn't want to clutter up instructables with another thread that asked a simple question ( I did not take offense ;-) ).
10 years ago
But I didn't want to clutter up instructables with another thread that asked a simple question

Stop doing that !!
Your questions deserves as much spaces than any one else questions.

Don't you think a forum full of interesting questions (and thus, of potential answers and solutions) would be more beneficial to the Instructable community (and to the rest of the world through search engines) than a forum full of "this or that" games or "k'nex SVR11 machine gun of the death" ?