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.
This 12V battery charging circuit automatically shuts off at the end of the charge. The disconnect...
We do not know exactly what sound a flying saucer makes, or if it makes a sound! But this is not...
This simple 1 transistor circuit was found in an American documentation from the 60's. The...