A Planet Analog article, “2N3904: Why use a 60-year-old transistor?” by Bill Schweber, inspired some interest in this old transistor and how it’s commonly used, and if any uncommon uses might exist.

A friend recently sent me an email noting that the classic 2N3904 bipolar transistor was now 60 years old. Since its “birth” was before I got involved with basic electronics, that callout was ...

Here is a quote from another website... "Note that the 2N2222 / 2N2907 (also PN2222 / PN2907) transistors will safely handle 8 to 10 times as much current as the 2N3904 / 2N3906 transistors. Meanwhile ...