• Ternary computing: basics

      Balanced ternary


      I am working on a computer architecture principles lectures for our university; and as an assignment I'd like to propose to my students to build a simple programmable machine working in ternary. The main reason is fun: as a lecturer I must bring a bit of entertainment, otherwise I won't be listened to. Besides, it is important for historic reasons. Any further «why?!» questions will be answered «Because I can».

      This page describes the very basics, it won't go beyond a simple ternary adder (and its hardware implementation). Stay tuned for more.

      I chose the balanced ternary system: every trit represents one of three possible states, -1, 0 or 1. A very extensive description of this system may be found here.


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    • Naïve Math: the Mendocino motor and Earnshaw's theorem

      • Tutorial

      The problem statement


      I was surfing the Internet the other day and a rather curious thing caught my mind: the Mendocino motor. It’s an extremely low-friction bearing rotor: the original one had a glass cylinder hanging on two needles, but the modern ones use magnetic suspension. It’s a brushless engine: the rotor has solar batteries attached to it, which generate current for the coils wrapped around the rotor. The rotor spins in a fixed magnetic field, the solar batteries getting exposed to the light source one after the other. It’s a rather elegant solution that’s very possible to recreate at home.

      Here’s the video that explains how it works (in Russian):


      But this video had another curiosity even stronger than the engine itself. In the video description Dmitry Korzhevsky writes: “You CAN’T replace the side support with a magnet! Don’t ask me about this anymore!”
      I LOVE the 'impossible' word!