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.
Found in a 1967 RCA documentation, this circuit can be made with equivalent SCRs according to the...
This simple circuit with SCR and unijunction transistor appeared in Radio Electronics magazine in July...
We found this circuit in a Radio Electronics from October 1963. The circuit uses an output...