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need Help with making a Counter with a 7 Seg Display

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Configure your 7490 as a BCD counter. The instructions on what pins to connect where are in the data sheet for the 7490. Use the BCD outputs to drive the BCD inputs of your 7448. The a-g outputs of the 7448 will correspond to the segments of your display. I dont recall if the 7448 can drive the display directly, you might need to use a buffer for extra current to the display.

Dr Nine

New Member
Thanx that should help....

Whould a simple NAND gate Fix the Prob that it seems to count from 0-15

But i only need it to count to ten...


Hopefully someone else can confirm, but as I recall the 7490 counts 0-9 then resets. If that is not the case, then the part has an internal NAND connected to the reset of each of the register bits. So you can make it reset on any combination of 1 or 2 bits.


Active Member
7490/7448 counter

Yes the 7490 is a decade counter. If you ground pins 2,3,6,7,and 10.
Vcc to pin 5. Tie pin 1 to pin 12, this will also be the A out. The clock to
pin 14.
The 7448 will drive low current common cathode displays.
:lol: Ned
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