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.

[Paulo] just tipped us about an Excel based high frequency transistor amplifier calculator he made. We’re guessing that some of our readers already are familiar with these class A amplifiers, commonly ...

Chairman of the Senate Judiciary Committee Senator Chuck Grassley (R-IA) attends an oversight hearing of U.S. Attorney General Pam Bondi, on Capitol Hill in Washington, D.C., U.S., October 7, 2025.

Abstract: In this article, we present a novel equivalent circuit model for a dual-band unified absorptive common-mode filter (A-CMF). While existing single-band A-CMFs effectively address ...

Two tuners were developed for this receiver. The more sensitive one uses tetrode transistors in the RF amplifier, mixer and oscillator. Its disadvantages lie in a much higher cost and a 12 to 14 db ...

Abstract: Common-mode chokes (CMCs) have been widely used in power electronics applications, which not only mitigate electromagnetic interference (EMI) but also safeguard the assets’ immunity. Circuit ...