This document discusses various digital logic components including registers, counters, and memory units. It describes shift registers which allow parallel or serial loading and shifting of bits. Several types of counters are examined such as ripple counters, synchronous counters, and up/down counters. Finally, it covers different memory cell designs and configurations for RAM including logical construction and examples of 1Kx8, 4Kx8, and 1Kx16 RAM.