This simple charger was found in a 1980s documentation. The transistor may be the TIP42 with a heat sink. R1 adjusts the load current. The transformer has 1 A of secondary current.
This circuit came out in an American magazine that no longer exists. It's the Electronic...
This receiver was found in the Radio Electronics magazine of March 1953. It tunes to the medium wave...
The presented circuit uses an LM3900, transconductance operational amplifier. It was found in the...