DIY power supply

I recently stumbled across some pictures I took when I was building my first power supply, which I thought were lost, and so I've decided to make an instructable about it.

In this instructable I'm going to show how to build a fully adjustable PSU with dual output, this power supply is ideal for beginners as it is indispensable for powering many circuits with a wide variety of voltage inputs, it also can deliver enough current to power most of the circuits a hobbyist could build.

From my experience, this PSU isn't only easy to build, but it's also very reliable and tough, I've never had to change the regulators after all the abuse it has gone through, and this includes HV discharges, short circuits and many other crazy stuff that has destroyed ICs, mosfets, and many other electronic components. I'm really impressed with the performance of those regulators.

If you have checked my videos or my other instructables you'll see this is the power supply I normally use, and it's been working quite well even after all this time.

Step 1: How it works

The design of this PSU is really simple, it is based around LM317 regulators, which are controlled using a resistor and a potentiometer, it basically acts like an operational amplifier, but instead of amplifying a signal, it decreases it's voltage, using a feedback loop to keep it constant.

For the input voltage source I've chosen a laptop charger, they are more compact than a transformer, and they deliver more current for the same space.

This PSU also has a double output, this means it has two independent regulators, this comes very handy when testing circuits that require various voltages. A switch on the top controls which voltage is displayed, since there is only one display.