Have a look at the required inputs of the CD4511B:
display D C B A 3 0 0 1 1 5 0 1 0 1 9 1 0 0 1
You do not need the 10-line to BCD encoder or inverters; you can route the switch outputs directly to the 7-segment decoder (as active-high signals with pulldown…
Part Number: ULQ2003A Other Parts Discussed in Thread: CD4511B ,
Using appropriate biasing with diodes and resistors, could the ULQ2003A be used as constant current sink if there would be one or two diodes (whatever number is needed for appropriate biasing…
