This small audio amplifier circuit in complementary symmetry was found in the 1974 Mullard Databook. The output pair can also be the BD135 and 136.
This sensitive two-transistor circuit was found in the June 1965 Radio Electronics magazine. The...
This circuit, obtained in an old publication, causes a second telephone bell to be played in a...
Found in a1969’s neon lamp documentation, this circuit uses a high voltage transistor. The output...