My digital design class in the mid 1970s used the older RTL (resistor-transistor logic) gates. They had only 2 NOR gates per (TO-5) package; you can still buy t

My digital design class in the mid 1970s used the older RTL (resistor-transistor logic) gates. They had only 2 NOR gates per (TO-5) package; you can still buy these on Ebay for around $6. At the time I wished that I could be using the much newer 7400 family of logic chips; the 7400 series by then had a full complement of chips available, everything from logic inverters to 4 bit arithmetic-logic chips (74181). The 7400 family is TTL and much better: higher density (4 NAND gates per chip for the 7400), easier to work with packaging (DIPS), higher speed, much greater variety of chips, and most importantly to me a higher fanout (each output signal can drive inputs on more downstream chips making designs simpler). The 74HC family used in the featured article came along around 20 years later. Many families of 7400 have been introduced over the years[1]. The 74HC family was one of my favorites for personal projects. They where logically compatible--the 1960s 7400 and the 1980s 74HC00 chips are both four 2-input NAND gates having the same pinouts in the same packages (14 pin DIPs). The reason I liked 74HCs was the fact that they used CMOS transistors and hence required very little power and could run on a wide range of voltages allowing simple battery powered circuits. I still have a supply of these from the 1990s that I bought for home projects. By now, half a century later, there are even more varieties. Some are suitable for hostile environments (like automotive applications--high temperature, wide voltage swings, electrical noise, and vibrations). Some will run on voltages under one volt and all run much faster. See [1] from Texas Instruments. [1] https://www.ti.com/lit/sg/sdyu001ab/sdyu001ab.pdf?ts=1680318581808 https://www.ti.com/lit/sg/sdyu001ab/sdyu001ab.pdf?ts=1680318...