In fact, the maximum output current of this source depends on the transformer which can be 6, 7.5, 9 or 12 V, depending on the desired voltage and current up to 1 A. The zener determines the output voltage. R1 is 470 Ohms and rectifier diodes of type 1N4002 or 1N4004. The transistor must be equipped with a heatsink. Filtration can be improved by increasing the value of C1.
