Scratch filter (CB22152E)

This filter for scratched disc noise was found in an English documentation from 1989. The integrated circuits used are still common today.

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Transistors and Diodes Tester (CB18658E)
This simple circuit makes it possible to test diodes and transistors for generating use and medium...
1 to 25 V power supply (CB8892E)
This 2.5 A power supply was found in a 90's QST magazine. The power transistor must be mounted on a...
Digital capacitance control (CB7552E)
This circuit is a digitally controlled variable capacitor. We found it in American documentation from...