Found elsewhere in this section, this circuit mimics the noise of a steam locomotive. This was obtained from an Electronics Today International of the 1980s.
The integrated circuit is from the time. This low-power circuit was found in the April 1973 issue...
This small amplifier, close to 1 W, was found in a 1963 documentation. The class B circuit uses...
This source of constant current was obtained in an American documentation of 1973. The transistors can be...