This circuit generates signals from 10 Hz to 10 kHz. We found it in a Popular Electronics from the 90's. The components admit equivalents.
We found this circuit in an old documentation from the 70s. The sensor is an LDR that must be...
This circuit with junction field effect transistors was found in documentation from the 1980s. The...
Common general purpose silicon diodes when direct biased provide a voltage fall of about 0.6 to...