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Resistors are [not] boring.

Resistors are often thought of as the most basic and boring of electrical components. It's almost true, they just happen to be one of the most useful of electrical components as well. However, traditional classroom explorations involve breadboards and multimeters, serial and parallel circuits, Kirchoff's law, and generally nothing useful. For this tutorial, I'm going to assume you've had the fortune of sitting through one of those lectures, and know the basic resistor forumulas,

  • V = IxR or "Ohm's Law", describing how voltage, current, and resistance interact
  • for series circuits, where the resistors are connected one after another
  • for parallel circuits, where resistors are connected heads-to-heads and tails-to-tails

If you don't, you do now, and will pick the rest of it up as we move along.

Ohm's law, Power, Energy, and Work

Ready for highschool physics? Awesome.

In your kit, you should've found a pair of packages of resistors, both nearly identical. One's 100 ohms and one's 1000 ohms.

Let's find out which one is which. Resistors are color-coded - the colored bands on the resistor body encode the value (in ohms) and the tolerance (percent deviance from the ideal.) Now, you can either memorize the chart, go to Wolfram|Alpha, or, alternatively, ignore the bands. Grab one of each and shove them into the output header of your cee, from channel A to ground and channel B to ground.

Now open up pixelpulse, hit and let's figure out which is which.

The slope of the lines is your resistance. In this particular instance, Channel A had the 100ohm resistor attached to it, color code . Channel B had the 1000ohm resistor attached, color code .

Turn whichever channel has the 100ohm resistor up to 50mA and let's do a little bit of math.

When we pass 50mA through a 100ohm resistor, you can quickly figure out that it's supposed to result in "5V." What does this actually mean, though? The general idea is that passing current through a resistor requires a voltage differential eqeual to the resistance multiplied by the current. This is simple enough to explore.