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.

Abstract: Fused filament fabrication (FFF) was used to additively manufacture (3-D print) two-prototype circuit-analog (CA) absorbers. The CA absorbers consist of a lossy frequency selective surface ...

Have you ever wondered how speed guns measure the speed of moving vehicles or how an athlete's sprint speed is recorded? Normally these speed sensors work with radar or laser technology to bounce back ...