u/bmercury

I'm finding conflicting info online depending on where I look and wanted a straight answer. Some sources say the pitch or effective diameter is a function of the major and minor diameter at the midpoint, some say it is a direct measurement of P/2, which can also be found by measuring the fundamental triangle of the crest and root and getting the midpoint of those.​

Is my understanding right that pitch diameter is only reliant on the form of the thread and the major diameter does not factor in at all? Measuring with pitch micrometers on a truncated crest thread and getting differing ​results. Thanks.