This classic windscreen wiper interval setup was found in American documentation from the 90s. The circuit can be found with variations at other points on this site.
This amplified circuit was found in a magazine for radio amateurs 73 of the 90s. The circuit uses an...
This circuit drives an old tape recorder when an audio signal is received. The circuit is...
This circuit can be used to recognize a tone by its frequency. When this tone is present in a...