I know this is probably going to be a moronic question but as of right now I am a bit confused by this particular circuit.
The circuit in question is not my own and is from here:
http://roznerd.blogspot.com/2009/12/2-digit-7-segment-updown-counter.html
For example, what is the purpose of R21? When S3 is up, the resistor is bypassed, but when down it still connects the input to the 5v rail. I also question R39 for the same reasons.
The video on the blog shows the circuit working so I guess it's OK, probably just be me not understanding it properly.
The only thing I think I am sure of is that IC1C should have the unused inputs tied to ground
The circuit in question is not my own and is from here:
http://roznerd.blogspot.com/2009/12/2-digit-7-segment-updown-counter.html
For example, what is the purpose of R21? When S3 is up, the resistor is bypassed, but when down it still connects the input to the 5v rail. I also question R39 for the same reasons.
The video on the blog shows the circuit working so I guess it's OK, probably just be me not understanding it properly.
The only thing I think I am sure of is that IC1C should have the unused inputs tied to ground