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Engineering

  • J7-31: VISIBLE HARD DRIVE

    J7-31
    See what the guts of a fixed magnetic drive look like.
    At one gigabyte, this 3.5 inch hard drive was too small to be useful, so we cracked it open for all to see.
    J7

  • K2-47: SPEEDOMETER MODEL

    K2-47
    Demonstrate operating principle of some speedometers.
    Two conductive discs are placed parallel and coaxial to each other, one mounted to a manual roator, the other suspended from a wire. The lower disc, on which a magnet is mounted, rotates when the handle is cranked. Induction causes the upper disc to rotate through an angle which is dependent on the torsional constant of the wire support and the rotational speed of the lower disc. The upper disc is damped by a magnet held in place on a tuning fork. The lower photographs above show details of the assembly. This idea is used in some auto speedometers, where the wheels are attached to the lower disc and the speedometer indicator is attached to the upper disc.
    K2, K1, D1

  • K7-42: BARRICADE FLASHER

    K7-42
    Demonstrate a barricade flasher circuit.
    This is the device which is often seen along highways to call attention to a barricade in the road. It is a bit more complicated than a simple RC circuit, but does use an RC time constant to control the rate at which the lamp flashes. All of the circuit components are embedded in a block of waterproof plastic, which can make them hard to see in class.