Purpose:Demonstrate reflection of pulses from fixed ends and free ends.
A pulse generated at the left end (photograph at left) reflects off the right end. The reflecting end can either be fixed (clamped, center photograph) or free (right photograph).
• Encourage students to make a prediction before each combination as to whether the wave will reflect, and whether that reflection will be upright or inverted.
• This can be combined with demonstration G3-05, showing that fixed and free end reflections are the extreme cases of partial reflections due to a change in impedance.
Like any wave in a transmission medium, when the medium ends the energy in the wave has to go somewhere. The wave is reflected back from the end. With a free end, the wave reflects identically; with the end clamped, it reflects inverted.