This LM380-based circuit was found in documentation from the 1980s. The components are current, and the transistor may be a general-purpose equivalent. Note the use of a medium impedance speaker.
Found in an old Radio Electronics, this circuit uses common components today. The resistors of the IC...
This circuit was published in an article in Electronics Now magazine in October 1995. The circuit...
This DC-DC converter was found in old RCA documentation. The circuit operates at 15 kHz. The...