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This audio filter was found in the August 1993 issue of Radio Electronics magazine. It cuts low and high frequencies corresponding to rumble and scratch noises that occur on turntables.
This simple circuit for switching RF signals was found in an RF Design from the 90s. The circuit...
I found this circuit in a Popular Electronics from 1992. The circuit can be easily implemented with BC549...
This circuit was found in a 90s EDN. Its purpose is to increase the efficiency of operational...