This proximity sensor was found in a 90s Popular Electronics. The base is a PLL567 that operates at around 100 kHz. The circuit operates by capacitance sensing.
This circuit was found in an Electronics Now of 1988. The circuit is still current, and the power...
With this name, we found this electronic stethoscope with a coal microphone in a 1957 Raytheon...
This transistor amplifier with complementary symmetry configuration can provide approximately 1 W...