Based on the CA3140 IC, this circuit was found in the June 1986 issue of Radio Electronics. Sensitivity adjustment is made using a trimpot in series with the sensor.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...