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.
The purpose of this circuit is to automatically turn a water pump on and off. Sensor 1 is the...
This circuit was found in Motorola's 1967 documentation. The circuit makes use of power...
This interesting circuit appeared in the April 1952 Radio Electronics magazine. The circuit is...