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.
In the figure we have a constant current source for Shape Memory Alloy or (Nitinol). The value of...
This circuit, which can be used safely, has been obtained in a 1987 documentation. It consists of a...
This circuit is from a Popular Electronics from 1992. It uses two SCRs and can be triggered by...