A ring counter is a type of counter composed of a type circular shift register. The output of the last shift register is fed to the input of the first register.

Ring counters are used in hardware logic design. The propagation delay of a ring counter will be a constant regardless of the number of bits in the code. The complex combinational logic of an adder can create timing errors which may result in erratic hardware Johnson counters have only one output hot at a time Johnson counter uses 5 rather than four flip-flops, but can be decoded to 10 outputs with only 2-input gates for a net saving in CMOS technology.