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.
The frequency of this type is oscillator is given by the RC network. Calculations can be found in...
This configuration, which appears in other points of this section and website with small...
This circuit is from the 1960 Mullard transistor manual. The transistors are germanium from the...