5K10.48 - Current Coupled Pendula
Place the coils on the table in a vertical position and connect them together with banana cables. Suspend the iron block and magnet masses in the coils so that the line of magnets on each block is free to oscillate in both coils. Start one of the magnet sets oscillating in one coil and the magnets in the other coil will quickly start to oscillate also. Depending on how you connect the two coils with the banana cable, you can make the coils oscillate in unison or 180 degrees out of phase.
With the addition of a lecture bench galvanometer, you can observe the direction and change of directions of the current running through the coils. Connect the coils in series with the galvanometer. Make sure you are using the current connections on the galvanometer. You will not need to use a shunt on the galvanometer unless you wish to use very large amplitudes on the magnets.
- Harry Manos, A Simple Demonstration of Induction, emf........", TPT, Vol. 17, #2, Feb. 1979, p. 112.
- Mark Davids, R. Stephen Rea, Paul Zitzewitz, "Demonstration C: Motor - Generator (Speaker-Microphone)", Teaching About Lightwave Communications an AAPT/PTRA Manual, p. 3-8.
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