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view/download model file: Series-circuit9.nlogo
This model shows siimulates a series ciruit where two different wires are connected in series with each other between two terminals of a battery.
The model "Ohm's Law" shows how current and resistance emerge in a wire in light of Drude's Free Electron Theory. In this model, instead of a single wire connected between the battery terminals, two wires (denoted by the black and the yellow patches) are connected in series with each other. This configuration is called a "series circuit". The total current (I) in the circuit depends on the voltage (V) and resistances of the two wires (R1 and R2) as
Since resistance in teh wires is inverseky proportional to the drift-velocity (d1 & d2) of the free electrons in the wires, one can write
I = (Constant) * (d1 + d2)
The two plots show the number of electrons reaching the positive terminal of the battery as a function of time, and current as a function of time. The later plot is the slope of the first one.
What is the general nature of the "Current in the wire" plot in all cases (i.e., does the plot resemble a circle or parabola or a straight line)?
What happens when you run the model for short periods of time (a few secs)? What happens when you run the model for long periods of time (a few minutes)?
Does the model obey Ohm's law?
Keep everything else constant, just change the height of the wire (i.e., in a 3-D world, you are changing the cross section of the wire). You can do this by using the downward pointing arrow in the control strip along the top edge of the view (if you place your mouse over the arrow it says "CHANGE THE HEIGHT OF THE WORLD"). How do you think cross sectional area of the wire affects current?
Keeping everything else constant, just change the TOTAL-ELECTRONS in the model and run it. How does current depend on the total number of electrons in the wire? How does resistance depend on it (no. of electrons in the wire)?
When a particle moves off of the left edge of the screen, it doesn't re-appear by wrapping onto the other side (as in most other NetLogo models). However, electrons do wrap vertically.
Electrostatics, Polarization, Charged Particles, Conductor, Ohm's Law, Lines of Force
To refer to this model in academic publications, please use: Wilensky, U. (2005). NetLogo Conductor model. http://ccl.northwestern.edu/netlogo/models/Conductor. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.
In other publications, please use: Copyright 2005 Uri Wilensky. All rights reserved. See http://ccl.northwestern.edu/netlogo/models/Conductor for terms of use.