We found this configuration in a 70s American documentation. The circuit makes use of operational amplifiers of the time. Modern equivalents can be tested.
This circuit amplifies signals from 0.5 Hz to 300 kHz. We found it in an old documentation. Equivalent...
The circuit presented is from the 1993 Motorola Linear Interface ICs. Other operational may be...
This circuit doubles the frequency of an audio signal, thus changing its timbre. The circuit was...