Follow the parts. Change a control. See how a whole system responds.
These explanations connect an observable change with the mechanism behind it. Each includes an interactive model, a written walkthrough, source references and the assumptions that limit the demonstration.
← All explanationsAn incandescent light bulb makes light by heating a thin tungsten filament with electric current. The hot wire emits thermal radiation, including visible light and infrared. Two separate leads connect the filament to the bulb’s terminals, while a sealed glass envelope protects it from room air.
Explore the model and explanation →A transformer changes AC voltage through mutual induction, without a moving mechanism. Alternating voltage on the primary produces changing magnetic flux in a shared steel core. That flux induces voltage in the secondary. In the ideal model, the voltage ratio equals the winding turn-count ratio, while the current ratio changes in the opposite direction and power is conserved.
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