This high impedance step suggested by an English publication can operate up to 1 MHz with 1 V rms output. Input impedance is 1 M ohm.
This Intersil circuit was found in a 1980s documentation. Operational are of the time, but current...
New Low-Power PIC24 “GA7” Microcontroller Family Now Available CHANDLER, Ariz., Dec. 12, 2016 — The...
This circuit was found in a 1976 NASA manual, making use of components of the time. The transistor...