This circuit was obtained from an American 1980s documentation. The frequency depends on the crystal and the circuit may be a PNP that reaches the generated frequency.
This sensitive microammeter was found in documentation from the 1980s. The accuracy of the circuit...
This circuit produces modulated tones in a loudspeaker. The effects can be adjusted by the...
We found this circuit in an old documentation from the 70s. The circuit can use any varicap and...