The 74-series TTL ICs are designed to be used over a very limited supply voltage range (4.75-5.25 V), and - because they generate very fast pulse edges and have relatively low noise-margin values - must be used with supplies with very low output impedance values (typically less than 0.1 Ω).
Assuming that the matter of fan-in and fan-out has already been taken care of (as described in Part 2 of this mini-series), four other basic usage themes remain, and these are described under the headings Power Supplies, Input Signals, Unused Inputs, and Interfacing.
It is usually a fairly simple matter to design logic circuitry using “74-series” TTL ICs, provided that a set of TTL basic usage rules are observed.
