Scratch is the scratching noise that occurs mainly with old records. This high frequency noise is eliminated by the filter found in the February 1990 issue of Radio Electronics magazine.
Equivalent operational amplifiers can be used in this circuit of the 1990 Linear Databook,...
This is another one of the many versions of Nicad battery chargers that we have on the website and in...
This simple transistor tester circuit was found in the February 1968 issue of Radio Electronics magazine....