This primitive solar radio was found in a Gernsback publication from 1960. The transistor is made of germanium of the time and the earphone is magnetic with high impedance.
This circuit was found in the November 1993 issue of Electronics Now magazine. It uses...
This circuit was found in a Popular Electronics from the 90s. The effect circuit uses components...
In the circuit shown in the figure, when the input voltage rises to 27 V, the TL431 triggers the...