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 simple circuit with bipolar transistors is from a 1970s American documentation. The RF...
This circuit is from a Linear Technology integrated circuit manual from the 1990s. The circuit...
CTS IoT Quartz Crystals Available through Mouser Electronics, CTS quartz crystals are especially suited...