An ultra-low power sensor operates using energy harvesting from various sources for efficient monitoring. The oscillator ...

A popular transmitter back in the day was based on the Hartley oscillator (PDF link). Using only a single triode tube and a tuned circuit with coils wound from 1/4″ copper tubing, Hartley ...

The style of the transmitters are based on [Ralph Hartley]’s oscillator circuit built for Bell Telephone in 1915. Most of the components he uses are from the time period, and one of the tubes he ...