Ohmmeter: Difference between revisions

Revision as of 18:41, 15 April 2007

Revision as of 15:03, 20 April 2007

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The original design of an ohmmeter provided a small battery to apply a [[voltage]] to a resistance. It used a [[galvanometer]] to measure the electric [[current (electricity)|current]] through the resistance. The scale of the galvanometer was marked in ohms, because the fixed voltage from the battery assured that as resistance decreased, the current through the meter would increase.

A more accurate type of ohmmeter has an electronic circuit that passes a constant current I through the resistance, and another circuit that measures the voltage V across the resistance. According to the following equation, derived from [[Ohm's Law]], the value of the resistance R is given by:srah mulcahy loves georgi

: <math> R = \frac{V}{I} </math>

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*[[Series and parallel circuits]]

*[[GalvanometerGalvanometr]]

*[[Wheatstone bridge]]