Alternating Currents

  • EM1.1 AC Generator Models     ACGenerator

    These are small apparati that manually create AC current. One has spinning magnets and another has spinning wire, showing that both methods work. The third is a hand cranked model that will light a bulb when the crank is turned sufficiently fast enough showing work generates energy in the form of electricity.

  • EM1.2 Lighting an Electric Lamp with a Match

    This is a transformer with a small spark gap. The primary turns are connected to 110 AC. Placing a lit match in the gap ionizes the air and allows the passage of current. A lamp in series with the gap is lit. A spark then appears in the gap. Once the spark is blown out, the lamp dies out. While the transformer is still active, it would be wise not to get too near the spark that will be present in the gap.

  • EM1.3 Red ELRC Board

    This is a big board with an indicator, capacitor and resistor mounted on it. The voltage across each component may be displayed on an oscilloscope which the class can see on the monitors (see CAMERA). Begin with a DC component input into the board. Let the class notice the effect of changing the component. Then input the AC current. Each device has an on-off switch. By placing an output to Channel 1 which represents to the input current and the other on Channel 2 which represents the output voltage, the class can see the phase difference across different components, or combination of components.