This circuit was found in a Popular Electronics from the 90s. The transistors are general purpose, and the gain depends on the ratio between R2 and R1.
Found in Popular Elecronics, this configuration also appears in this section, but obtained from other...
This circuit was obtained in an old French publication from the 80s. The maximum power of the lamp...
Found in a 1966 American publication, this circuit invert the phase of a low frequency signal. The...