This filter configuration used in telecommunications uses 4 Jaumnann crystals that are interesting for low and medium frequencies. The circuit is from an 80's documentation.
This small medium wave radio was manufactured in the 1960s in Japan. The circuit is powered by 4...
This transistorized receiver was found in Popular Electronics from February 1968. Transistors are...
We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit can...