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.
Although not using transformers, this amplifier may have difficulty mounting if the original...
This flip-flop or bistable multivibrator is triggered by a signal applied to the base of the...
The integrated circuit used in this regulator is not very common today. The circuit is from old...