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 crowbar protection circuit for non-regulators blows the fuse when the load voltage exceeds a...
This circuit locks when the sensors are opened. The relay can be 6 or 12 V depending on the power...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...