Sunday, June 28, 2009

Electronics is fun

Those with a passing familiarity with electronic components will, in all likelihood, consider this just plain silly. However, as I have long had an interest in electronics combined with an apparent irrevocable curse when it comes to actually building a working circuit, I found this experience comforting and inspiring.


Central to modern electronics is a device called the transistor. It allows a small current to control a larger one, which essentially means it's an amplifier.


The upper of the two schematics below shows a circuit that doesn't work. Your skin allows small amounts of current to pass, but if you hook your skin to a 5 volt power source, the current coming out of it won't be enough to light an LED. The second schematic, though, is the one I just built, and shows a transistor in action. The fact that it actually worked still makes me grin. For that matter, it also got Andrew fairly excited -- he likes that kind of thing.


The working circuit allows the tiny current from your skin into a transistor. That convinces the transistor to allow lots of current through, which is adequate to light the LED. Better still, the tighter you grab the wires, or the wetter your hands, or in short the better a conductor you are, the brighter the light gets.


Now what I'm not sure of is why this works when I only grab the wire going into the transistor. I don't even have to is greater than my power supply's ground potential. I haven't seen it light up brighter when I shuffle my feet on the carpet; that would be cool :)


Update: Ok, I do know why this works -- the ground potential here is more positive than the ground potential in my power supply, which in turn is based, I guess, on the neutral level at the power plant (my power supply doesn't use the ground plug in the outlet here). So current flows from me and everything else to the power plant even if I don't hold the positive wire.


Sunday, May 3, 2009

Friday, May 1, 2009

Tuesday, April 28, 2009

More geeky database stuff

I tend lately to post geeky stuff on the company blog instead of here. Those interested should refer to this page to see the latest on that front.

Thursday, March 26, 2009

Spread the Joy

With my day job comes the opportunity to create posts on the company blog. It seems of more value to the company if I put database-related techie nerd posts on their blog rather than on this one, and the value to me is probably sixes either way. That said, this blog post simply serves as notice to those few (approx. 1) of my many readers (approx. 2) who care about such things that there's a new database-related techie nerd post available for perusal.

Saturday, March 14, 2009

Fun With SQL

Later this week I'll be presenting at the Utah PHP Users Group meeting about neat stuff you can do in SQL. I've finished the first draft of the slides, here.

I'm not much of a PHP fan, and not necessarily always quiet about that fact, so extra thanks to mindjuju for the invitation.

Sunday, February 22, 2009

Lily videos

Doting parent that I am, I couldn't rest until I got this videos posted. Well, ok, I have a newborn, Karlyn's stuck in bed most of the time, and the boys are sick, so I haven't been able to rest anyway. But here are some videos.

Saturday, February 21, 2009

Baby's here

After nearly two weeks more waiting than we originally expected, Lillian Elizabeth was born Wednesday, and I'm getting around to posting pictures, here. More from a very helpful sister and brother-in-law, here.

Lily weighs about 0.68 stone (66,500 grain, 0.13 talents) and is a little over one cubit long (about 1/400 of a furlong).

Unrelated note: This is a fun online unit conversion utility.

Monday, February 2, 2009