4 digit 7 segment CC – all digits count the same number

7segmentdisplaycountermultiplexer

enter image description hereUltimately I'm looking to build something that's going to count revolutions as part of a guitar pick up winder.

I've got a circuit hooked up with 4 x 4026 counters going into a 4 digit 7 segment display. I believe I have the correct linking of the chips withe carry from one going into the clock of the other. But every time I provide a clock pulse all 4 digits on the display increment by 1 rather than just the least significant.

I have the pin outputs from each of the chips going into the corresponding cathode of the 7 seg display but I just cannot get it to count more than 0 – 9.

What am I getting wrong?

This is my first question on here. I'm new to electronics and have been working at this for a few days but always run into the same problem. Really appreciate any help.

Thanks for the comments and answers so far. I've added what I hope passes for a circuit diagram…

I think I've got the clock in and carry out (/10) connected correctly and I think I've got the right outputs going into each of the common cathodes on the display. I'm not worried too much about re-setting or inhibiting the clock right now so I've put them to negative. I'm not doing anything with Pins 4 and 14.

The LED on the left is just another method of me knowing a clock pulse should be going in

Best Answer

According to your schematic, you have the outputs of all counters connected in parallel, and to the anode inputs of your display. You have all cathode leads of the display grounded. This will force all digits to display the same number.

The display you have needs a multiplexed input. You will need seven 4:1 multiplexers between the counters and the display, with the segment outputs of counter 1 going to input 1 of the multiplexers, counter 2 to input 2, etc. You also need to arrange to ground one cathode lead of the display at a time, switching the mux and cathode selection in sync, so that display 1 will be enabled when the mux selects counter 1.