Unformatted text preview: RC Circuits A circuit consisting of one resistor and one capacitor can exhibit exponential behavior due to the time it takes to charge the capacitor and to the resistor’s prevention of unlimited current flow. The curves shown below are intended to remind you of the nature of an exponential equation of the form et/ τ where τ (“tau”) is called the period or time constant of the curve. Of course, a decaying exponential does not really have a period of repetition, so tau is defined by how long it takes the curve to fall to 37% of its previous value. (Essentially, when t= τ , the equation becomes e –1 , which is about 0.37.) Also shown in the figure is the mirror image of the decaying exponential et/ τ , which is given by 1et/ τ (shown with a dotted line). Notice that subtracting from 1 flips the curve upside down. In theory, both of these curves take forever to reach values they approach, but for all practical purposes, they are within one percent of the limit after less than five time periods. the limit after less than five time periods....
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 Spring '11
 Tibbets
 Radioactive Decay, Charge, Current, RC Circuits, RC circuit, Exponential decay

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