The signals from this circuit obtained from the 1965 Radio Shack documentation are picked up from a medium wave receiver. L1 and L2 have 80 to 100 turns of yarn 28 on a ferrite rod.
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
With this name, we found this electronic stethoscope with a coal microphone in a 1957 Raytheon...
We find this oscillator in a 1980s documentation. The frequency depends on the crystal and the...