Second Order Harmonics

"NOTE: Graph data was taken on a random sample using an Audio Precision Model APX555 Audio Analyzer."
.well.. ok? that's from a pretty big transformer manufacturers datasheet. apart from other parts of the datasheet being intentionally misleading, it's weird to point out you took a 'random' sample of a graph with high precision instruments. why not an average or detail how you sampled? because mean engineers might read this as: you took the one that fitted you best after 10.000 repetitions, after all - whats "random"? are we talking chosen by a CSPRNG? probably not. the data-sheet has further issues when clarifying THD+N clearly or frequency response. Oh. and by the way, that particular transformer, as nice as it is for some use-cases (probably) costs in the multiple hundred EUR (like 3-400 upwards) per piece.

homework: figure out what's wrong with that (compare to a TI or ADI datasheet).

— [AZ (Aaron Zauner)]

A short history on OpAmps (Operational Amplifiers) by ESP:

Opamps - A Short History Opamps - A Short History