This circuit operates from 20 Hz to over 20 kHz and is easily tunable. We found it in a 70s documentation. The circuit can be implemented with modern operational amplifiers.
We found this antenna amplifier or Booster circuit in an Electronics Now from the 90s. The circuit...
We found this circuit in the Linear Applications Handbook of the 1994 National Semiconductor. The...
This circuit is from a 1976 Motorola power semiconductor manual. In it we have the optical...