Convert Leds to 7 Segment Display

[mechie]

Apologies all round

laroche73
I took the liberty of a MOD-EDIT on you excellent posting simply to correct the truth table layout.
It displays correctly (monospaced font) if you surround such things with the {code} and {/code} markers (note curly brackets to avoid triggering that mode here !).

 

[laroche73]

LM3914 vs. LM339

Thanks for correcting my truth table, mechie. Not only were the spaces squished out, I accidentally posted the wrong truth table. It was for a LM3914 instead of the LM339 circuit. Since I can't go back and edit the post, I've included a corrected version of the schematic, for both the original LM339 and the LM3914.

Mosfet had suggested replacing the LM339 comparators with a LM3914 dot/bargraph display driver, so that only one led is on at a time. Sebi's diode ROM idea looks better with the LM3914, using 27 diodes.

The partial decoding method also works well with a 3914, although it requires one more gate than the 339 circuit did (8 XORs and 1 inverter, or 9 XORs). This is with the "off" condition translated to a "0" on the display.

- CAL