The Visual Electricity Demonstrator (VED) is a linear diode array that serves as a dynamic alternative to an ammeter. A string of 48 red light-emitting diodes (LEDs) blink one after another to create the illusion of a moving current. Having the current represented visually builds an intuitive and qualitative understanding about what is happening in a circuit. In this article, I describe several activities for this device and explain how using this technology in the classroom can enhance the understanding and appreciation of physics.


At the time of publication, the product described in this article appears only to be available through Arbor Scientific. Although the author has previously been in the employ of Arbor Scientific, this article is unrelated to that working relationship. The author is in no way being compensated by Arbor Scientific for the writing of this article, nor through the sale of the item. The author independently recognized the value of using this apparatus for the teaching of physics and is the originator of many of the demos described herein.

Note from the TPT editors: The editors concur that this material has sufficient value for the physics teaching community to warrant publication despite the appearance of competing interests.

To see the Visual Electricity Demonstrator in action, check out James Lincoln’s video abstract at TPT Online, E-PHTEAH-55-019706.
I am basing this argument on the free-electron gas or Drude model of electron flow in conductors. For a good resource on this model, see
Solid State Physics
Saunders College
Fort Worth, TX
), Chap. 1.

Supplementary Material

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