5J20.10 - L-R Time Constants

Code Number:
5J20.10
Demo Title:
L-R Time Constants
Condition:
Good
Principle:
Inductor Time Constants
Area of Study:
Electricity & Magnetism
Equipment:
500 mh Standard Inductor, Resistor Box, Wave Generator (Wavetek), Oscilloscope (Tektronix 2235).
Procedure:

Arrange the generator, resistor, and inductor in series as shown. Set the generator to the square wave function. Measure across the resistor and observe the trace. Measure across the inductor and observe how the trace changes.

References:
  • Carl E. Mungan, "Double-Exponential LR Circuit", TPT, Vol. 43, # 8, p. 519, November 2005.
  • S. Y. Mak and P. K. Tao,  "Measurement of Self-Inductance",  TPT, Vol. 26, # 6, p.  378, September 1988.
  • Jim Oliver, "Observing Voltage Phases in RC, RL, and RLC Circuits",  TPT, Vol. 35, # 1, Jan. 1997, p. 30.
  • Richard J. Duffy and Uri Haber-Schaim, "Establishing V = L (d I/d t) Directly From Experiment", AJP, Vol. 45, # 2, Feb. 1977, p. 170.
  • En-6, 7, Eo-11:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • B-315:  "Current Growth with Time",  DICK and RAE Physics Demo Notebook.
  • B-320:  "Growth/Decay with Square Wave",  DICK and RAE Physics Demo Notebook.
  • B-470:  "Calculate from Voltage Reading",  DICK and RAE Physics Demo Notebook.


Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.