This guide is intended to aggregate a great tool to your electronics workbench that will save your life many times :
Imagine that you have a single DC power supply that gives you 12v, and you need to supply 3.3v to your circuit, or 5V, or any other voltage between 1.2v and 10v.
Now, you can do it with just 3 components - LM317 IC, 100-400 ohms resistor , and a 10K or 5K potentiometer.
LM317 - 0.5 USD
180 ohms resistor - 0.05 USD
10K ohms Potentiometer - 1.5 USD
Total - 2.05 USD
I live in Brazil, and here electronic components are more expensive than other countries like US, so if you live in another country probably your cost will be lower, but still, I'm very happy.
That's right! I will teach you how to assemble this very simple circuit, that makes life way easier for you, that want different voltages on every project, for a very low cost.
You are not limited to 12V as input voltage by the way, is said on the LM317 datasheet that it supports "any output voltage" as long as ( Vin - Vout ) < 40v - I have not tested with high voltages, but I imagine you won't need them eighter.
You can use it on a breadboard or assemble a PCI and mount it on a box, so it will look nice and will be always at your side in the needed moments. The tutorial covers only the circuitry needed and I stopped it on the breadboard.
Let's proceed and see what's needed