I asked ChatGPT.
Do you know what User 74LS138PC is?
The ChatGPT
74LS138PC is one of the TTL (Transistor-Transistor Logic) series of logic ICs (Integrated Circuits) and has a function called 1-of-8 Decoder/Demultiplexer. This is an IC that allows you to select one of eight output lines (Y0-Y7) using three low potential (LOW) input lines (A, B, C).
The 74LS138PC was introduced in the 1970s and was widely used in digital circuit design. Among other things, they were used for memory address generation, multiplexer/demultiplexer configurations, and selection circuits. The 74LS138PC has different output signal delay times depending on the type of IC, so by making an appropriate selection, it is possible to optimize the design for a specific application. It is still used in some digital circuit designs as a classic TTL logic IC.