A classroom demonstration of wireless energy transfer

Investigating wireless power transfer

“…One very straightforward experiment immediately suggests itself: is there a frequency, for any given coil set-up that will give optimum power transfer? We set about finding out 4 [1].…”

“…One topic that is bound to raise its head sooner or later is that of wireless charging. Already there are phones on the market 1 that can be charged by simply placing them on a special mat and, in time, we will see these appearing on tables in coffee shops and fast-food outlets around the globe. Without getting too caught up in the details 2 it is possible to both explain the Physics of how these devices work and encourage our students to investigate the phenomena involved.…”

Hardware for hard-up schools?

“…Using the 'frequency sweep' function on the signal generator it becomes apparent that the amplitude of the signal on the oscilloscope is greater at higher frequencies. It should be possible to carry out the experiment outlined by Luczak and Baker [5] with this apparatus (plus a small capacitor) to determine the resonant frequency. This could be further developed into explanations about radio waves and tuning.…”

“…In its familiar form, connected to a speaker, it has now been thoroughly eclipsed by any computer that has speakers. A wide variety of free software exists for generating tones of a range of frequencies, including the excellent freeware program Audacity [5]. Zeitnitz's Scope software also has a signal generator built in which not only generates sine wave, square and sawtooth tones at the click of a button, but will also perform frequency sweeps between pairs of values over a determined period of time.…”