Summary

Simple Bench Power Supply

It is great to have a bench power supply that provides 4 different voltages at the same time (see my other thing, 'Another ATX bench power supply' here)... BUT if you only need a simple power supply AND you happen to have an old Dell 19.5V laptop power supply in your drawer... then this is a simple - easy to build - bench power supply for you.

Description

I installed everything in a 3D printed box (bottom, top, front and back panel plus a small cable clamp). This box has the same 'footprint' as the ATX power supply mentioned above. I added a couple of extra elements :

Parts needed for this project

• Dell 19.5V laptop power supply here or in your drawer.
• DPS5005 adjustable power supply here.
• LM2596 buck convertor here.
• Switch (230V) like this one
• Binding posts (2 red - 2 black) here.
• Terminal/choc block (at your local DIY shop)
• Rectangular LED (2x5x7 mm) and a 220 Ohm resistor here.
• 10 M3x10mm bolts (6 to assemble top and bottom of the box, 2 for the cable clamp, 2 for the LM2596)
• Some wires, soldering iron, heat shrink tube, glue gun, screwdriver, multimeter.

Instructions

You will need to cut the power cable of the Dell power supply to be able to install the switch at the back of the box.

First secure the cable with the cable clamp to the bottom of the box, then mount the switch above it.

Use some glue to fix switch, terminal block, DPS5005 and LED.

Make sure you only work on the wiring, connections and soldering with the power supply unplugged !

The LM2596 module will bring the 19.5V down to 5V for the binding posts on the left of the front panel - adjust the potentiometer so you have exactly 5V on 'OUT'.

The DPS5005 will provide a second - variable - voltage (between 0-19.5V) for the binding posts on the right.

In case you mainly work on projects that need 3.3V, you could adjust the potentiometer on the LM2596 accordingly (I included a front-panel with the text "3.3 V" ).

In that case you don't need the 220 Ohm resistor.

Be carefull when you mount the back panel so it's not inside-out, the round hole should line up with the cable clamp.

Printed with 25% infill, 0.15mm layer height, no supports.

Enjoy!

Update March 2021 :
Uploaded 3cm shorter version of box top and bottom (not tested!)