Characterizing Voltage Sources: Finding V0 and r using a Variable Resistor

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SUMMARY

The discussion focuses on characterizing voltage sources by determining the open circuit voltage (V0) and internal resistance (r) using a variable resistor connected to a battery. Participants confirm that V0 is measured at the point where the current is zero, which corresponds to the y-axis intercept on the graph. Additionally, the internal resistance can be calculated using the short circuit current. This method effectively characterizes the voltage source.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with circuit diagrams
  • Knowledge of graph interpretation in electrical contexts
  • Concept of open circuit and short circuit conditions
NEXT STEPS
  • Study the concept of open circuit voltage in detail
  • Learn how to calculate internal resistance using short circuit current
  • Explore the relationship between resistance and current in circuit analysis
  • Investigate practical applications of voltage source characterization
USEFUL FOR

Students in electrical engineering, physics enthusiasts, and anyone involved in circuit analysis and voltage source characterization will benefit from this discussion.

mitsuruangel
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Homework Statement


A variable resistor, R, is connected to the terminals of a battery (dashed box in the diagram). The graph below shows data collected in the circuit as R is varied. What is V0, in volts?

What is the internal resistance, r, in ohms?

should the V0 be measured at the top of the line where it is at the smallest current? because that is what the TA explained to do, I tried and I can't seem to get it right
 

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Did you extend the line backwards to where I=0(where it cuts the y axis)
 
mitsuruangel said:

Homework Statement


A variable resistor, R, is connected to the terminals of a battery (dashed box in the diagram). The graph below shows data collected in the circuit as R is varied. What is V0, in volts?

What is the internal resistance, r, in ohms?

should the V0 be measured at the top of the line where it is at the smallest current? because that is what the TA explained to do, I tried and I can't seem to get it right

And adding one more question to Dadface's post, what is special about where it cuts the y axis?
 
that worked! thanks
 
mitsuruangel said:
that worked! thanks

But why did it work. Do you understand that part?
 
Because V0 should be at lowest current (ie when it is 0) but the internal resistance keeps it from actually getting there?
 
mitsuruangel said:
Because V0 should be at lowest current (ie when it is 0)

That part is correct. V0 is the "open circuit voltage", so when no current is flowing. The other thing you can use to figure out the internal resistance is the "short circuit current". Once you have V0 and Rs, you have characterized your voltage source.
 

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