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7 segment sed driver/decoder circuit help Answered

Ive looked all over, and have already tried 3 circuits, but none work. They have either the wrong ic, wrong led display, etc. So, I want to make a circuit that, by using a decoder, I can flip 4 dip switches and make the display make certain numbers. I have a 7447 ic, common cathode led display, but I can only either find a circuit with a 7447 and a common anode, or a circuit with a common cathode but a different decoder (a latch/decoder/driver). Here is the first site I tried:

http://www.allaboutcircuits.com/vol_6/chpt_7/9.html

And when I finally flip the switches, nothing happens even though I made it exactly as shown. But it has a CMOS, so thats probably a big problem. I also tried this site:

http://www.atilim.edu.tr/~hkar/lab5.htm

But it has a common anode, and when I tried it it didnt work. I have exactly ELS321HDB. And I have a power unit that can go from 5 - 18 volts. Can anyone show me how to make this? Im not too good yet at reading circuit diagrams, because I seem to make it way more complex then it should be.

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harryjri (author)2011-10-19

I've been playing with 7447 chips over the last few days, and it does seem like it is only for common anode 7 segment displays.

The allaboutcircuits.com link you list above uses a 4511 chip, which my research tells me is good for common cathode 7 segment displays.

If anyone wants to add to or discuss my answer, feel free. HTH

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101yummYYummy101 (author)2009-05-03

By the way, I also have 74248 and 74347

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