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EMF and Terminal Voltage
![Schematic Representation of a Voltage Source](../../../../../../../../../figures.boundless-cdn.com/13505/full/figure-22-02-02.jpeg)
Schematic Representation of a Voltage Source
Any voltage source (in this case, a carbon-zinc dry cell) has an emf related to its source of potential difference, and an internal resistance r related to its construction. (Note that the script E stands for emf. ) Also shown are the output terminals across which the terminal voltage V is measured. Since V=emf−Ir, terminal voltage equals emf only if there is no current flowing.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"OpenStax College, College Physics. November 7, 2012."
http://cnx.org/content/m42357/latest/?collection=col11406/1.7
OpenStax CNX
CC BY 3.0.