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.
Found in a publication by National Semiconductor, this circuit provides an output voltage of 3.3...
This circuit produces rectangular and triangular signals using two 741 operational. The source must...
Found in Elektor Electronics from the 90s, this circuit produces the tone of 1 750 Hz for calling VHF...