Sequential Logic Gates
Dale R. Patrick, Stephen W. Fardo, Vigyan Vigs Chandra · River Publishers eBooks · 2020
Digital systems employ a number of devices that are not classified specifically as logic gates. These devices play a unique role in the operation of a digital system. Such things as flip-flops, counters, registers, decoders, and memory devices are included in this classification. This chapter discusses truth tables, logic symbols, and the operational characteristics of these devices so that they may be used more effectively when the need arises. AND, OR, NOT, NAND, and NOR gates are considered to be combinational logic circuits. The other part of this classification deals with sequential logic circuits. Logic gates are the building blocks of combinational logic circuits. A flip-flop is the basic building block of a sequential logic circuit. To explain the operation of a flip-flop, people use the circuitry of a bistable latch. The term bistable refers to a device that is capable of assuming either one or two stable states or conditions.