It’s hard to believe there are only a couple of weeks left in 2009. It’s been a great year for TechStuff. Not that we’re quite ready to say goodbye to 2009 yet. In the near future, you’ll be able to hear how Chris and I scored on our predictions for 2009, following up on a show we recorded at the end of 2008. And in another episode you’ll hear us prognosticate on what we can expect in 2010.

This week, we focused on a listener mail request and a more general discussion. The request was about Project Natal, Microsoft’s innovative video game controller system. Microsoft unveiled the control interface at the Electronic Entertainment Expo last June. Gamers will be able to play video games without using a controller at all. They can also scan normal devices to act as a controller within certain games (thanks to all the TechStuff listeners who wrote in to remind me about that — it slipped my mind during the recording). In the episode, Chris and I talk a little about the history of controllers as well as what we think the future will be.

Wednesday’s episode was all about the theory behind electronics. We discuss the relationship between current, voltage and resistance. We also give a brief overview of what a circuit is and why it’s important. Oh, and I take some pot shots at a beloved figure of American history.

I also have a couple of corrections to post about that episode. At one point, I mention that an electric current can induce a magnetic field. That much is correct. But I went on to say that the magnetic field generates opposite the flow of current. That’s a goof on my part. Magnetic fields are circular around a wire — we think of them as at a 90-degree angle from the current. Here’s an illustration showing a cross-section of a wire and its magnetic field:

If you could stare down the end of an electromagnet wire and see the fields, this is what it would look like.

Thanks to listener Jim from New Jersey for setting me straight.

The second correction is more of a clarification. We mention the danger of coming into contact with high-voltage electricity. Listener Drew wrote in to point out that it’s technically the current, measured in amperes, that is deadly rather than the voltage. This is true — the current is what will kill you. But in resistive circuits, current and voltage are proportional. If a system is high-voltage, it’s a safe bet that the current is also flowing at dangerous levels.

Thanks for listening and keep tuned for our year-end specials coming up later this month!