Suggested by an American publication, this circuit has 5 operating conditions indicated in the diagram. The circuit can be designed based on modern equivalent transistors.
We found this shield circuit in the SGS Integrated Circuits Manual of 1982. The circuit is...
This circuit with transistors and a crystal microphone appeared in Radio Electronics magazine in...
This circuit amplifies the signals in the UHF band starting at 470 MHz, reaching just over 900...