[Concept] Ultra-Basic Power Supply with Square Function

Cover from Clive Darra (Flickr)

  • This concept have not been tested but feel free to get inspired.
  • Assembly planned.

On my everyday electronics, i mostly use scrap electronics for prototyping. Because of my low money and because it always be greener than order a box of 15000 units who will never be used.

Even more when comes the question of power devices.

When battery-powering is misfit , i often use Phones, Laptop and Coaxial power-supply . One scissors-cut and two pin-soldering later and here we go with a “quite stable” , low-cost power source ready to be plug on classic breadboard.

But if i want 3.3v or 5v (or more), with a better stabilization the previous build doesn’t do the job because fundamental tension is native.

Of course , commercial “maker” power source and desktop-PC power supply are good choices and not this expensive. But some people like to do things on their own 😉

The main idea is to create an ultra-basic system , PCB-like, for supplying circuits without overstocking the breadboard. The second one is to improve the system by adding a square function generator for all the purpose tensions.

I will continue to use my stone age power-source because it delivers 7.35V of tension (for 6v announced) for supplying the new system.

Then i need to divide the tension with the right proportion of resistor for bringing out 3.3v and 5v (classic electronic voltages). However, soldering quality and parasite-frequency could be a problem if i want a clean signal, so i need to add tree capacitors in parallel.


I will also add a two way selector at the end for switching between AC (square function – not really AC but who cares) / DC , and later, 3.3v / 5v. The tree resistors + LED is just an indicator (power on/off)

As you can see, this is not amazing science but it’s a good beginning.

Now i need a square generator. The LMC55N is a well-know astable circuit who can be used as an oscillator with the correct neighbors components ( from 2 kHz until 16 MHz ).

I will use the incoming tension as power for the circuit, because it will set the amplitude of the LMC55N signal at approximately the voltage we choose before. Then , i will follow the schematic of the data-sheet for building my oscillator*.


*The most we add and the less it cost, the better it is. So instead of setting one capacitor for adjusting frequency value , i will add two other for getting ” :2 ratio ” in tree different output (+ 3 way selector).

In bonus part, i will add a transistor for allowing an output control with an external source (i call it “Pulse”). So i also add an another selector to the system.



The circuit will normally do the job , so i can end here.

Finally this system can provide a stable , multi-usage power source for less than 5 euros (including the PCB cost if you use salvaged components).

Remember , it’s just an idea , not a big deal.


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