How many volts of current are there in a bolt of lightning? That’s the kind of stupid question your local news anchor might ask while bantering with the weather guy. Perhaps your favorite cringe-inducing unit abuse is someone thinking light-years measure time or a model rocket enthusiast telling you that a newton-second is a little longer than a regular second. Of course, I made the same class of mistake when looking for a 1-amp battery, which I described in my previous post about battery capacity. That article addressed a specific instance of a general problem: not knowing or understanding units, which allow us to talk about and measure physical properties that we must understand whether we’re designing robots or baking cakes. Continued…

My earliest electronics projects and my first robot were powered by regular alkaline batteries, and I didn’t think about current or the capacity of those batteries. The batteries were prominently labeled “1.5V”, and I was happy in my understanding that putting four in a battery holder got me to 6 volts; when the motors slowed down, it was time for new batteries. When I began designing my second robot, I found some 12V, 1A motors (what a “1-amp motor” might mean is a topic for another post) and promptly wasted many hours dragging parents and teachers to Radio Shack and car parts stores looking for a 12V, 1A battery. Continued…

My name is Jan Malášek, which is a Czech name, so the “J” is pronounced as an English “Y” (if you care, we can go over the last name in person, or you can consult your local Czech person). I grew up on the Big Island of Hawaii, spent five years in school in Massachusetts, and then moved to Las Vegas, Nevada to work on Pololu. I recently turned 30, and I’m still not the millionaire I had hoped to become at age 23 and then by age 25. Hitting 30 means it has been twenty years since I got started with electronics and ten years since I routed the first circuit board that said “Pololu” on it. Continued…