This circuit was found in a 90s Popular Electronics. The sensor can be any phototransistor.
This traditional configuration was obtained in a 1986 publication. The speaker can be replaced by a...
This one transistor stage for audio signals was found in an old publication of the year 1958. The...
We found this 4-transistor receiver for the AM MW range in a 1960 transistor manual from Sylvania....
