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 is from old documentation but can be applied to modern equivalent components. The...
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This signal amplifier for ATV in the 427 to 439 MHz band was found in a magazine 73 for radio...