This circuit uses a 555 (according to the diagram) to generate 50 ms tone bursts at a frequency of 1.5 kHz. The circuit is from an 80's Electronic Design.
This circuit was found in a 1995 documentation. It drives a set of sequential LEDs from the sound...
An excellent signal generator for the audio track was found in a 1983 documentation. Its complete...
This circuit of a Popular Electronics is intended to control a wiper. The circuit consists of a...