This circuit amplifies signals from 0.5 Hz to 300 kHz. We found it in an old documentation. Equivalent transistors may be used. The gain is 20 dB.
We found this circuit in an old Radio Electronics. Components can be replaced by modern...
This circuit for the two-meter band of radio amateurs was found in 1980s documentation....
This circuit is used to generate pattern bars on an analog television screen for calibration...