Employing the XR2206 IC, this circuit was found in the May 1977 issue of Radio Electronics magazine. The formula next to the diagram gives the component values as a function of frequency.
This siren circuit was found in a Popular Electronics from March/April 1969. We can easily...
This power stage with two counterphase transistors and coupling transformers was shown in Radio...
This circuit is a sample of a DC amplifier used in the 50's. The transistor is germanium and very...