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 is a possible setting for a Colpitts oscillator operating in the audio track. The shunt coil...
We found this circuit in a 1992 magazine, but it can be easily assembled today because the...
This circuit of an old publication makes use of SCRs that admit modern equivalents. The frequency...