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.
This circuit makes use of an uncommon integrated circuit. It can provide a power of 6 W when...
This circuit was obtained from an English magazine from 1980, but as it uses components that can...
This circuit was obtained in a manual from the 1977 chain store Radio Shack. The circuit...