i want to count 1,2,3,4,5,6,7,8,9,10,11,12........ and then use the switching circuit (most left with the inverter) to count down. but it doesn't count down from 10, 9, 8, 7, 6 . Left 7 segment displays tens, right 7 segment displays ones.

how do I make count down start from 9 instead of 0? help pls. thank u

https://www.falstad.com/circuit/circuitjs.html, load this circuit to simulate, pressing switch enables count down....

 

Welcome to AAC!

I don't use Falstad. Could you post a schematic? If Falstad supports print to PDF, kindly post a black and white schematic; preferably without all of those animation artifacts.

Is this counter synchronous? You want to count 1,2,...12, but start counting down from a different number?

 

View attachment circuit-20220406-2332.png

circuit is the bottom one. falstad is free. can just download file and open file from there.

https://tinyurl.com/ya7u9gt9
thanks so much for help

 

circuit is the bottom one.

Your schematic is unreadable.

falstad is free. can just download file and open file from there.

I'm not interested in learning how to use Falstad.

 

heres a pdf

 

heres a pdf

It's still unreadable.

This is a 3 bit up/down counter I designed. The style I use is a combination of that used by Texas Instruments, Motorola, and RCA:

No vendors label the gate expressions; I do it so I and others can follow the logic (in case there are mistakes that need to be debugged).

EDIT: Here's an asynchronous design example: Not relevant