Potential Differences in a Circuit with an EMF Source

​
ℰ
0.66
r
0.4
The graphic shows the potential rises and falls in a circuit with a battery providing a source of electromotive force (EMF) of magnitude
ℰ
. The circuit contains a resistance
R
, as well as an internal resistance
r
. The associated changes in the potential add to
ℰ-ir
-iR
, when a current
i
passes through the points
b
(before the EMF source) and
a
(before the resistance) and back to
b
, with corresponding voltages
V
a
and
V
b
. These changes in the potential, when summed algebraically, must be equal to zero, by Kirchhoff's second rule.

Details

The following conditions hold for the potential differences in the circuit:
V
a
-
V
b
=+iR
and
V
a
-
V
b
=+ℰ-ir
.
For a detailed exposition, see D. Halliday, R. Resnick, and K. S. Krane, Physics, Vol. 2, 5th ed., New York: Wiley, 2001.

External Links

Resistor (ScienceWorld)
Resistance (ScienceWorld)
Electric Circuit (ScienceWorld)
Current (ScienceWorld)
Voltage (ScienceWorld)
Potential Difference (ScienceWorld)
Electromotive Force (ScienceWorld)
Kirchhoff Loop Rule (ScienceWorld)

Permanent Citation

Enrique Zeleny
​
​"Potential Differences in a Circuit with an EMF Source"​
​http://demonstrations.wolfram.com/PotentialDifferencesInACircuitWithAnEMFSource/​
​Wolfram Demonstrations Project​
​Published: March 7, 2011