Video : 
I built this laboratory power supply, back in the 7-8 grade in primary school. We have in Denmark, something called "youth school" Very roughly translated. It is basically evening school for teens. But you can attend to manny subjects, think that the at the time was nearly 100 subjects. And it's free,, here.
But, I built this power supply,In the electronics course and have been happy with it ever since. But it tends to blow the fuse.
and when I was on my way to buy new fuses for it again, I found a Automatic circuit breaker... or rather 5, It is so cheap in China.
http://www.aliexpress.com/snapshot/6016928432.html
I do the install, in this video.