Found in a Raytheon transistor manual from the 1950s, this circuit uses one of the first commercially available transistors, the CK722. The circuit is for using a small speaker as a microphone.
April 2017 - Texas Instruments bq51222 integrated circuit for chargers and other Qi wireless power...
Using two 567 PLLs, this circuit recognizes two audio tones in sequence providing a signal for a...
This solar powered circuit was found in a 1991 documentation. The transistor is a general purpose...