Instructables

Desktop Voltage Regulator/Power Supply

Picture of Desktop Voltage Regulator/Power Supply
If you are an electronics student, hobbiest or pro you surely have the usual problem of supplying the right voltage to your devices and circuits.

This instructable will take you through the process of making a variable power supply (voltage regulator really) that is able to output 1volts to 17volts from 12volts 1000mA input (standard dc adapter).

The main schematic isnt mine but other than that its all my work, i also replaced the 1N5402 with 1N4007 since i didnt have the first available, the 4007 is much power full than the 5402 and it can handle up to 1000mA (which is our current rating), other than this diode every thing else is easy to find and available in most electronics shops.
 
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Step 1: Materials

The following materials are needed for this project:

1x LM317 regulator
2x 1N4001 diode
1x 1N4007 diode
1x 1k resistor (for the led)
1x 220R resistor (R stands for 0 right hand zeros i.e. ohms)
1x 18k resistor
1x 470uF 40+ v electrolytic capacitor (minimum rating is 40v any thing higher is ok)
1x 470nF ceramic capacitor
1x 4.7uF 40+ v electrolytic capacitor
1x 10uF 40+ v electrolytic capacitor
1x 100n ceramic capacitor
1x LED (i used 5v blue LED so any thing between 1.5 and 5 will work and any color of course)
1x ON-ON switch (3 legs)
1x DC adapter jack
1x 10k potentiometer !!!LINEAR!!!

1x 4x7 cm blank PCB

Others:

Ferric Chloride etchant
Acetone
Glossy paper

I used some old computer screws to make stands for the board, so u r free to either use the idea or just get creative :)

Tools:

Water resistant marker (for fixing broken traces)
Laser Printer
PCB Drill
Solder iron
Solder
Cloth Iron


Step 2: The schematics

As i mentioned before this is not my work, i just stumbled upon this schematic while browsing the web.
CI-05_Sept07.pdf(595x842) 84 KB

Step 3: The PCB design

This is the PCB design, i had to make this one on eagle since it wasn't supplied.

the powerPCB.pdf is a blank (no components visible), powerSchematic.pdf is for placement and powerSchematic2.pdf is a reference for placement (use it with the schematic to find out the components' values)
powerPCB.pdf(595x842) 12 KB
powerSchematic.pdf(842x595) 22 KB
powerSchematic2.pdf(595x842) 10 KB
65GTO5 years ago
What would the current limit be on this unit. I need about 5 amps and I have a transformer large enough to handle the current. If not could you recommend alternatives. Thanks
oaky8 65GTO4 years ago
oaky8 65GTO4 years ago
same here. i need about 3 amps, a little less. also need it to have an overhead voltage of ~ 1v
stormer18095 years ago
This is a nice project, but I have to add a few comments.
1. An LM317T is nominally rated for 1.5 Amps only. This means the maximum you can draw is 1.5A.
2. The regulator has an overhead voltage of about 3V. Running from a 12V supply, you'd be able to get an adjustable range of 1.2V to 9V
3. Be careful of the Total Dissipated Power(TDP). If regulated to say 5V, there is 7V dropped across the regulator. Now say that you are running a light bulb consuming 800mA. The TDP for the regulator is 7V x 800mA = 5.6Watts. This will require a heatsink to get rid of the heat generated.

Hope this helps.
cam543215 years ago
This looks great, but a few pictures would be helpful.
cousine (author)  cam543215 years ago
yes i am sorry abt that, only decided to write down the instructable after i was done !!! anyway i am doing another project that i will photograph each step, they will be similar except for the design on the pcb, i will update this instructable with the link once am done
Ya that is what I guessed, maybe if you added a few more photos of the finished product that would help also.