This circuit uses a resonant reed relay to recognize the frequency of an input signal. Adaptations can be made to obtain functioning as a shield. The circuit is from 1965 documentation.
This is the typical circuit of an FET amplifier stage in the common source configuration. The circuit is...
This voltage-controlled oscillator was found on an Elektor from the 90s. The components are from...
We found this circuit in an English publication from 1980. It provides a logical output signal when...