Bench Power Supply (PSU) tutorial

Apologies, this videos isn't "short" and there's much to say. Hope you'll see the (good) use of a bench power supply with this tutorial. The cheapest kind of bench PSU you can use is this 18V / 3A model : http://www.amazon.com/Tekpower-HY1803D-Variable-Power-Supply/dp/B000CSQK5E/ref=sr_1_4?ie=UTF8&qid=1379688216&sr=8-4&keywords=bench+power+supply My best bargain choice would be currently something like this: http://www.amazon.com/Mastech-Single-Output-Power-Supply-HY3003D/dp/B004ISQ270/ref=sr_1_2?s=industrial&ie=UTF8&qid=1379688309&sr=1-2&keywords=bench+power+supply