This circuit was found in an English publication from the 70s, an article that teaches how to calculate instruments. The circuit is still current and can be built with an analog indicator of 100 uA.
Suggested by a 90’s Radio Electronics, this circuit automatically activates the recording switch of an...
Found in a 1960s Electronic Design, this circuit provides a signal from the sensing of an analog...
Operating at a frequency of around 180 kHz, this transmitter was found in a Science & Electronics...