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Demonstrating Chaos with “Sprott Circuits”. Michael Braunstein Central Washington University PNACP, April 15 and 16, 2005 University of Portland. Non-Linear Dynamics and Chaos is rapidly becoming a standard component of the undergraduate physics curriculum, e.g.:
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Demonstrating Chaos with “Sprott Circuits” Michael Braunstein Central Washington University PNACP, April 15 and 16, 2005 University of Portland.
Non-Linear Dynamics and Chaos is rapidly becoming a standard component of the undergraduate physics curriculum, e.g.: • Analytical Mechanics, Fowles and Cassiday, 6th Edition; Classical Dynamics of Particles and Systems, Marion and Thornton, 4th edition. • Classes: Computational Physics, Nonlinear Dynamics and Chaos • Laws, P. W. (2004). "A unit on oscillations, determinism and chaos for introductory physics students." American Journal of Physics72(4): 446-452. • Physics is an experimental science – hence instruction requires: • Demonstrations • Hands on activities • Laboratory Exercises
“If it’s chaotic, then how can we measure anything?” Physics Student
Mechanical Chaotic systems Kinesthetic - less abstract; Typically slower evolving; Transducers to measure; Mechanical skill level/expense for assembly Berdahl, J. P. and K. V. Lugt (2001). "Magnetically driven chaotic pendulum." American Journal of Physics69(9): 1016-1019. Nunes, J. E. B. G. and Jr. (1997). "A mechanical Duffing oscillator for the undergraduate laboratory." American Journal of Physics65(9): 841-846. VERSUS Electronic Chaotic systems More abstract; Audio frequencies or higher; Voltage output, Electronic skill level for assembly; Components are inexpensive Roy, P. K. and A. Basuray (2003). "A high frequency chaotic signal generator: A demonstration experiment." American Journal of Physics71(1): 34-37. Jones, B. K. and G. Trefan (2001). "The Duffing oscillator: A precise electronic analog chaos demonstrator for the undergraduate laboratory." American Journal of Physics69(4): 464-469. Wiener, R (2005). Controlling Chaos in a Simple Electronic Circuit, PNACP (unpublished).
Publications introducing “Sprott” systems: • Sprott, J. C. (2000), "Simple chaotic systems and circuits," American Journal of Physics 68(8): 758-763 • Kiers, K., D. Schmidt, J.C. Sprott (2004), "Precision measurements of a simple chaotic circuit," American Journal of Physics 72(4): 503-509.
C R Vin - Vout + LM741
R V1 R1 V2 R - + LM741 Vout
Sprott, J. C. (2000), "Simple chaotic systems and circuits," American Journal of Physics 68(8): 758-763
Sprott, J. C. (2000), "Simple chaotic systems and circuits," American Journal of Physics 68(8): 758-763
Circuit Analysis Rv BTW: Can be expressed as three coupled first order ODE’s Notes: Scaling of time; Rv is the control parameter (don’t use voltage divider)
D(x) X=0 X=0 V Diode = Braunstein (Wiener, et. al)
Demonstrating Chaos Audio Amplifier and Speaker
Investigating Chaos Oscilloscope
Investigating Chaos Computer Data Acquisition and Analysis NI-DAQ LabVIEW
NI-DAQ LabVIEW Investigating Chaos Computer Data Acquisition and Analysis with computer controlled (voltage controlled) resistor -LM13700
What Else ? • Full Characterization of the strange attractor • Other Sprott circuits and other chaotic circuits • Synchronization of chaos (tuning/encryption) • Control of Chaos
Thanks to the following Central Washington University students: Sam Rowswell David Cross Erika Beam Ryan Tervo Alfredo Meza