Experiment 13 - The synchronous 4-bit UP/DOWN Counter

To obtain a synchronous 4-bit UP/DOWN counter, you can continue the chain of the 2-bit counter...

Take a look at the circuit diagram. You recognize the UP/DOWN counter from the last experiment. You can continue the chain, as all extra logical gates are already present...

Circuit diagram 4-bit UP/DOWN counter.

You could expand the chain even further...

In the next experiments, you get to know two more unusual counters, the so-called ring counters...