Testing some 555’s

IMG_20140730_000849I’ve been going through some of my things, seeing if there’s anything I need as Dipmicro is currently having a sale. I saw I had some 555 timers which I’ve never used… sort of. The two 555’s I have are from the kit I had to buy before I started college. I was excited to get started before the first semester began so I attempted to wire a random circuit I found on the internet even though I had no idea what I was doing. Of course, the circuit never worked and I put the 555’s away. We never used them in any courses.

I decided to wire up a testing circuit. I simply Googled “555 timer test” and found a schematic for this. If you get flashing LEDs, the 555 is still alive. My two are still good. On the theme of components I don’t use often, I decided to go with these yellow LED’s for the test. I have yet to use any of them in any project. The photo does make it look like they would make good outdoor lights. They’re just a little lighter than a “warm white”.

So that’s just a random thing I did. From it, I realize I’ve been kind of “lazy” in that I always rely on microcontrollers all the time. I could probably use a 555 timer for the lighting I did for a shelf. I’ve always wanted to revisit that project because I think I’ve learned some new skills and techniques that would make it more efficient and free up the ATmega328 microcontroller and breadboard…

The case of the sizzling power bar…

For the past week or so, the power bar that sits on the edge of my desk  has been making some crackling noises. I thought it was the one adapter plugged into it with some restless capacitors. As days went on, the noises were getting louder and today I got a whiff of something burning. Of course, I had to pull the plug… and explore.IMG_1153Opening it was not difficult; Just six screws to pop. The yellow wrapper around the surge protection circuit was harder to get off.IMG_1156As I popped the circuit and the power rails out of the plastic casing, one rail immediately fell off. I thought it was fine because I figured it was the plastic casing holding it all together, and I guess that what they thought too. It’s actually soldered as the other rails stayed on.IMG_1160I suspect this loose connection is what all the crackling was from.IMG_1161The surge protection circuit consists of three MOVs, or metal-oxide varistors, and a thermal cutoff fuse. The MOVs basically act as an overflow valve: Too much voltage and it conducts to send the extra to ground. I’ll be salvaging the power cord, toggle switch, and thermal fuse. I’ll keep the MOVs too if the legs are still a decent length.

So that was pretty fun. Except the part about how I’m out of a power bar.