While working on recreating an “ancient” (read: 60-year-old) logic circuit type known as resistor-transistor logic, [Tim] stumbled across a circuit with an unexpected oscillation. The oscillation ...

For battery-powered circuits, it is easy to build an ultralow-current crystal oscillator designed around a 32.768-kHz crystal. This crystal is common for real-time-clock circuits. Because these ...

Fig 1. This Pierce-series resonant oscillator can reliably start at supply voltages as low as 2.4 V. It also draws very low current, ensuring long battery life. Fig 2. An oscilloscope photo shows the ...

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.