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.
July 2017 - Texas Instruments' new 3 A bq25601 single cell battery charger can be found on Mouser...
This circuit was found in old documentation. PUTs are uncommon components today. The circuit...
This simple timer with unijunction transistor was found in an old American technical...