This filter that rejects a frequency range determined by the double-T was found in the August 1993 Electronics Now magazine. The source must be symmetrical.
This interesting circuit was found in an English documentation. It generates sound similar to...
This circuit was found in an American magazine in 1978. It activates a relay when the speed of a...
This circuit for the power grid was found in the June 1969 Radio Electronics magazine. The SCR and...