Bilateral current source 2 (CB20819E)

We found this circuit in an American publication from the 1980s. Equivalent modern operational amplifiers can be used.

Injector and Continuity Tester (CB4452E)
This useful instrument has dual function, operating both as signal injector and continuity tester. The...
Audio Compressor and Expander (CB19612E)
This fully passive circuit was found in documentation from the 1970s. The circuit uses an optical...
FM 5 octave wave antenna (CB18032E)
This table with the antenna design allows to size the antenna according to the frequency of the...