We found this circuit in a 1973 publication. The circuit lets frequencies below 480 kHz pass through with an output impedance of 1k. The circuit can be implemented with current operational.
We found this circuit in a Radio Electronics from October 1976. The components are still common, but...
LEDs with appropriate resistors can be used in place of the lamps in this circuit obtained in a...
Datasheet of We found this circuit in the 1982 SGS Linear Integrated Circuits manual. A | table...