Found in older Signetics documentation, this circuit generates signals from 30 Hz to 25 kHz. Operational amplifiers are from the time, as is the matching pair of transistors.
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs...