This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is from 1975 documentation. The transistors can be the modern BF494 equivalents.
The TPA3100D2 integrated circuit from Texas Instruments (www.ti.com) consists of an efficient...
This circuit was found in a 1965 General Electric publication. The circuit can be adapted to...
This circuit, which combines a bipolar with any JFET, was found in the April 1993 issue of...