We found this circuit in a 1969 Mullard documentation. The same configuration appears elsewhere in this section. The control range is -2 dB to 19.5 dB at 30 Hz.
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...