My circuit is just a simple circuit really... What I have done is I've taken a Texas instruments DIP Decade counter SN74LS90 and feed it's output QA,QB,QC,QD to a Texas Instruments BCD to seven segment decoder/driver SN74LS247 and then feed it's output a,b,c,d,e,f,g to the respective inputs a,b,c,d,e,f,g to a Kingsbright SC56-11EWA seven segment common cathode display with 2K ohm pull up resistors between there outputs and Vcc.
I also took the same QA,QB,QC,QD outputs through 320ohm resistors and on to common cathode LED's.
My problem is the binary number indicated by the decade counting LED's does not match the output of the display.
Do I need more buffering? If not...could you tell me what's wrong?
