Levers are literally all around us. You body uses them to move, pick up a pen to sign your name and you’ll use mechanical advantage to make that ballpoint roll, and that can of soda doesn’t open ...

In last month's “Code Basics” article, starting on page 56 of the September issue, we spent most of our time discussing Class 1 circuits. Now, it's time to switch gears and focus on Class 2 and 3.