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.
The oscillator in the figure has its frequency determined by the crystal. The indicated value is...
This circuit activates an incandescent lamp (or LEDs) when the light stops hitting the sensor, which...
This didactic circuit was found in a 2001 documentation. It automatically counts in an increasing and...