7400 TTL series integrated digital logic circuits

Electronics
The 7400 TTL series integrated digital logic circuits are a five volt solution for most logic requirements. The 74Cxxx series provides the same function at other logic levels.

IC Letter Designations

A-Advanced                   S-Schottky
L-Low Power                  B-BiCMOS
T-TTL                               C-CMOS
F-Fast                              H-High Speed
1G-First Generation      2G-Second Generation
3G-Third Generation     A-Advanced
S-Schottky                      L-Low Power
B-BiCMOS                      T-TTLCCMOS 
Q-Quiet Outputs           V-Voltage
PPower

Families 

74 (Standard TTL)                              
74L (Low-power)                                     
74S (Schottky)
74LS (Low-power Schottky)
74AS (Advanced Schottky)
74F (Fast)
74xx Series List
https://en.wikipedia.org/wiki/List_of_7400-series_integrated_circuits