Power supply is for me the second most important lab tool after a good multimeter. It allows you to supply very accuratly all your electronics, without batteries or USB ports, with the good voltage and enough current.
If you plan to make your own electronic circuits one day, you will need a good power supply with you.
Today, I will show you how to make a powerfull power supply for less than 15 dollars, by sharing with you the plans I made for a french electronic association which I belong to. You will learn to choose and assemble cheap power modules and "hack" them to make your own bench top power supply from scratch.
This power supply is the result of many previous designs, and has now many features close to professional ones :
- No. of outputs : 2 outputs
- Outputs type : adjustable
- Outputs voltage max : 23.5 V
- Outputs voltage min : 1.25 V
- Outputs current max : 3A
- Overcurrent protection : yes
- Short protection : yes
Step 1: Warnings on High Voltages
Working with high voltages and power electronics involve some precautions to avoid an accident.
Step 2: Parts, Tools, & Skills
All the electronics parts needed for this project can be found on Digi-Key, which offer a large choice of components at the international. Choosing a good supplier ensures extra security for your electronic circuits, especially for power electronics like here.
I spent a lot of time on Digi-Key choosing the most appropriate components, at the same time efficient, simple and cheap. Feel free to choose other parts (for example an other AC/DC converter, more powerfull), a large choice of components is available on their website.
- 1x AC/DC converter 24V 6A (Digi-Key)
- 1x Toggle switch ON/OFF 16A AC (Digi-Key)
- 2x DC/DC converter module LM2596 (Digi-Key)
- 2x Linear potentiometer 10kΩ (Digi-Key)
- 2x Potentiometer knob (Digi-Key)
- 2x Toggle switch ON/ON 4A DC (Digi-Key)
- 2x Voltmeter display 0-30V (Digi-Key)
- 2x Self recovery fuse 3A 30V (Digi-Key)
- 2x Red banana socket (Digi-Key)
- 2x Black banana socket (Digi-Key)
- x1m AWG 20 multicore red wire
- x1m AWG 20 multicore black wire
- 50mm x 50mm MDF 3mm panel
- 7x 10mm M3 bolt
- 7x M3 nut
- 3x M3 washer
I used very basic tools to work on the different electronic modules, however, I chose to make a laser cut enclosure for this project since I have access to a fablab near my city. If you don't have the chance to have access to a laser cutter machine, you can 3D print one, drill into a plastic box or make your own with wood ! The enclosure is here just to protect your electronic circuit.
- Soldering iron & solder wire
- Glue gun
- Flat pliers
- Cutting pliers
- Laser cutter
- Basic soldering skills
Step 3: Laser Cut the Enclosure
To protect the electronic circuit and avoid any accident, all the electronic must be enclosed.
I have the chance to have access to a local fablab which own a 100W laser cutter machine, and I decided tu use it to make the enclosure of this project.
I chose MDF 3mm, which is cheap, very common and well suited for laser cutting. Each wooden piece was designed with Solidworks, exported into a .DXF file and finally edited and saved with Inkscape into a .SVG file.
Step 4: Overview of the Electronic Circuit
Step 5: Front Pannel Assembling
You will need :
- 1x Wooden front pannel, previously laser cut
- 2x Voltmeter displays
- 2x Toggle switch ON/ON 4A DC
- 2x Linear potentiometer 10kΩ
- 2x Potentiometer knob
- 2x Red banana socket
- 2x Black banana socket
Before soldering any electronic module, place each component of the front pannel. The front pannel includes all the controls for the two channels. Each channel is composed of 5 elements :
- the voltmeter display
The voltmeter shows the voltage measurement at the channel output. The measurements are quite accurate (± 10mV max) but must be verified with a professionnal voltmeter for precise applications. The voltmeter uses 3 wires : red (power +), black (ground 0V) and white (measure).
- the toggle switch
The toggle switch
Step 6: Back Pannel Assembling
You will need :
- 1x Wooden back pannel, previously laser cut
- 1x AC/DC converter 24V 6A
- 1x Toggle switch ON/OFF 16A AC
- 2x DC/DC converter module LM2596
- 7x M3 bolt 10mm
- 7x M3 nut
- 3x M3 washer
All power electronic modules used in this power supply are attached to th back pannel. It is composed of