In the original publication of the 90s a 556 consisting of a double 555 is suggested. The circuit drives a speaker with good power. The power transistor shall be fitted with a heat sink.
We found this circuit in a publication of 1991. The audio amplifier is an operational that admits...
Found in an 80's Hands On Electronics, this circuit turns on a light when it gets dark and goes...
This circuit regulates the output voltage of a 78xx according to the light incident on the sensor....