Category: Technical Articles

July 19, 2009 / / Electronics
Yay bench power!
Yay bench power!

WARNING WARNING WARNING! Switching power supplies have many BACs (beefy-ass capacitors) that can hold lots of juice long after you’ve unplugged the unit. Do not crack one open like I did without knowing what you’re doing, it could seriously injure you or at least be really uncomfortable when you shock the crud out of yourself. I’m not responsible if you do just that, don’t say I didn’t warn you. I have a cable I made with a brush at the end that grounds everything it touches, I use it to brush the back of all power electronics before I work on them. You should too.

This is a pretty common one, but I like to add flair. I needed a bench power supply. Sadly, bench power supplies are very expensive, and I’m a poor college student. What I do have are computers. Lots of computers. In fact, I just brought to the recyclers about 100lbs of computer waste from machines that are too slow for even my standards. Luckily, one thing computers have going for them is very refined, VERY powerful power supplies.

July 19, 2009 / / Electronics
USB metering goodness.
USB metering goodness.

A while back I wanted to monitor how much current my iPhone could draw under different conditions. I had seen a cable before where somebody brought it into a project box with a couple of screws on top exposing the two unshorted positive leads and the straight-through ground (such that you could measure both current through the cable or voltage across it), but I felt I could make things both smaller and more fully-featured.

July 18, 2009 / / Electronics