This circuit from Popular Electronics powers a small speaker. The transistor can be of general use and the capacitors can be altered to change the sound generated.
An FM receiver with good sensitivity and with acceptable sound quality in the strongest stations, can...
Exciting a sequential circuit with the output of a stereo we can make a set of lamps run at a...
The circuit shown was found in American documentation from the 1990s. The transistor can be of any...