Specification:Input voltage of 220 VOutput voltage ranges from 1.2 to 30 V (DC)

Schematic Diagram:

Materials:

(IC1)LM317T(D1-D4) 1N4001 Diode(D5-D6) 1N4007 Diode(R1) 220 ohm Resistor (R2) 12Kohm Resistor(VR1) 10Kohm Potentiometer(C1) 1,000uF 35 V Electrolytic(C2) 0.1uF 63 V Electrolytic(C3) 470uF 35 V Electrolytic(C4) 10uF 35V Electrolytic(T1) Transformer secondary coil 24V 1A

The layout of the PCB:

Pictures:

Test for Reliability and Accuracy (Trial 1)

Voltage OutputVoltage Output (Measured)Percent Error %

5 V

10 V

15 V

20 V

25 V

30 V

Test for Reliability and Accuracy (Trial 2)

Voltage OutputVoltage Output (Measured)Percent Error %

5 V

10 V

15 V

20 V

25 V

30 V