This circuit with 24 dB per octave attenuation was found in the November 1973 Radio Electronics magazine. The components are for 1 kHz but can be recalculated for other frequencies.
This 80s signal follower makes use of an audio amplifier of the era. The circuit can be adapted to...
This circuit makes use of a PLL 567 to invert the phase of a signal, ie to change it from 0 to 180...
We find this circuit in a 2005 Linear Technology manual. The circuit applies to small DC motors...