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.
This circuit has a waveform adjustment made with a potentiometer. C1 and R1 determine the base...
This circuit was obtained in an Argentine publication from 1973. The original version uses...
This circuit for the car can be found in other versions in this section. This is from an 80's...