Introduction: Adjustable 36W 24 VDC PSU

This is a simple instructable for a small size but powerful 36W power supply, 1.2 to 24 VDC, with digital meter reading and short protection.

Step 1: What You Need

1) 24V switchmode power supply, 1.5A (

2) 5 K potentiometer

3) IC LM350K

4) 5.1V 1W Zener Diode

5) 240 Ohm, 2X 2.4K. .5W resistors

6) 100uF 35 V, 10 uF 25V capacitors

7) LED (any color)

8) Toggle switch

9) 2 Banana posts (Red and Black)

10) 3 Digits LCD panel meter, 2 Vdc full range.

11) Metal or Plastic enclosure (Size 150 X 75 X 40 mm,) depends on the size of the panel meter and the power supply).

Step 2: Construction

1) Drill the holes for the IC (LM 350), This is a TO3 foot print.

2) Drill the holes for the PSU (Under side the power supply there are M3 screws, use the same foot print)

3) drill all other holes for the out sockets, switch, LED, potentiometer, inlet cable and DVM.

4) Install the IC on a heat sink, or if you use a metal box, use Thermal grease with appropriate insulator.

5) use 20-22 AWG wire for power line,

for all other connections smaller wire gauge will do.

6) Run the inlet cable thru a soft rubber grommet.

Step 3: Testing

1) Make sure all wire connection are tight and secured.

2) Turn on the power and verify that the switching power supply is 24Vdc, (green LED is on)

3) Connect a Multi-meter to the output, use a small screw driver and adjust the switching power supply out put voltage to read 24Vdc (As the LM350 has a 2.5-3 V drop, the switching power supply will be ~26-27 Vdc)

4) Connect a suitable load 16 ohm, 50 W resistor, or a 24V lamp and check for full load opertion.

That's All you are done!