The 74 series is a series of digital logic chips. They were introduced, along with the Mil-Spec 54 series logic chips, by Texas Instruments in 1964. 74 series logic chips are the de facto standard for small scale and medium scale digital integrated circuit designs.
The 74 series of logic chips contain chips implementing most digital building blocks, including logic gates, flip-flops, registers, and ALUs. There are over two hundred available 74 series chips, implemented in many technologies, including TTL and CMOS technologies. 74 series logic chips are manufactured by several different manufacturers.
74 series chips are commonly used for experimentation purposes, to implement glue logic, to implement designs produced in small companies, and even to build computers. Several popular minicomputers during the seventies were built out of 74 series logic chips.
These days, 74 series logic is not as prevalent as it used to be. With increases in technology, it is now easier to implement a design using a VLSI integrated circuit or programmable logic. FPGA designs are now replacing 74 series logic for experimenters and for students for the simple reason that it is much easier to implement a design using VHDL or some other HDL than it is to wire a design made out of 74 series logic and there is little or no cost benefit of using the 74 series chips over FPGA based designs.