Counters are divided into two categories, which are:
- Synchronous counters
- Asynchronous counters
Synchronous: They operate on a higher frequency than the asynchronous counter, they have one global clock which drives each flip-flop and allowing for output in parallel.
Asynchronous: The concept of a global universal clock does nit apply in asynchronous counters, as only one flip-flop is driven by the main clock, there by resulting in a sequence or order for input and output of the respective flip flops.