This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
This circuit, obtained in a 1983 magazine, can drive loads up to 100 mA if the transistors are...
This JFET amplifier stage was found in the Encyclopedia of Electronic Circuits Volume 5 from 1995....
The circuit shown in the figure uses two of the four operational amplifiers found on the LM324...