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VBench

  • K7-21: RLC CIRCUIT - 10 KHZ - RESONANCE

    K7-21
    Demonstrate resonance in an RLC circuit.
    Using the circuit above, the frequency of the oscillator is swept to find the resonance. Both the signal from the oscillator and the signal across the resistor are displayed on the dual trace scope. The capacitor (0-300 picofarads) and the resistor (0-100 kilohms) in the circuit box are variable. The increase in amplitude of the signal across the resistor and the phase shift at resonance are both easily seen.
    K7, ME2, ME3

  • K7-22: RLC CIRCUIT - 10 KHZ - DAMPED OSCILLATIONS

    K7-22
    Demonstrate damped oscillations in an RLC circuit.
    Using the circuit above with a 500-Hertz square wave, damped oscillations are shown on the dual trace scope. The upper trace is the applied square wave and the lower trace shows the damped oscillations produced each time the square wave changes. The circuit can be adjusted to obtain either underdamped, overdamped, or critically damped oscillations by changing the capacitance or the resistance. In the photograph above the horizontal scale is 250 microseconds per centimeter, the frequency of the square wave is 500 Hertz (period of 2 milliseconds), and the frequency of the damped oscillations is about 8000 Hertz (period of 125 microseconds). The capacitor is set to its maximum value and the resistor is set to about 20% of its maximum (20 kilohms).
    K7, ME2, ME3

  • K8-04: SPEED OF LIGHT

    K8-04
    Measure the speed of light

    A laser light pulse a few nanoseconds long is emitted by a light-emitting diode and immediately strikes a partially silvered mirror. The reflected light returns to a phototransistor to give the first pulse of the oscilloscope trace shown in the picture. The light transmitted through the partially silvered mirror reflects off a distant front-surface mirror, in the foreground of the picture, returning to the phototransistor to create the second pulse. The distance the laser beam travels, measured using a metric tape, and the elapsed time, determined from the oscilloscope trace, are used to calculate the speed of light.

    Please Note: Care must be used to position the light reflected from the distant mirror onto the phototransistor. This needs to be carefully monitored while in use, as environmental changes can affect it. Also, if there are issues of signal stability, check the trigger level on the oscilloscope to confirm that it is compatible with the trigger signal.

    K8, ME2

    K8-04A