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 Motorola documentation from 1978. The circuit is based on the LM324...
This crystal-controlled oscillator can generate signals up to a few dozen megahertz. We found it...
We found this circuit in the October 1987 Radio Electronics magazine. The circuit uses an...