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 astable was found in a European technical documentation from the 80's. The perfectly...
This circuit generates the busy tone of ordinary telephones. The transistors can be the BC548 and...
This is another one of the many sequential circuits that we have in this section and on the...