Induced Currents using Two Coils Demo
Induced Currents using Two Coils Demo
Induced Currents using Two Coils Demo
Induced Currents using Two Coils Demo
LED's of different colors mounted on small copper coils

 

Code Number: 5K10.30

Demo Title: Induced Currents using Two Coils

Condition: Excellent

Principle: Induced Currents due to Changing Currents

Area of Study: Electricity & Magnetism

Equipment: 

6 or 12 Volt Batteries, Lecture Table Galvanometer, Key Switch, Coils (2) #'s 1 & 2 or 3 & 4 are Matched Sets, and Iron Cores. Small copper coil (3 inch diameter), LED's of different colors mounted on small copper coils.

Procedure:

Connect the battery, one of the coils, and the key switch in series. Connect the galvanometer to the other coil. Place the coils side by side.  Depress the key switch and observe the deflection of the galvanometer. The deflection may be increased by inserting the iron core for greater classroom visibility. Note that as the switch is held down the galvanometer needle will return to zero as it is the changing of the fluxes that give the deflection. Choose your iron cores so that when both are inserted you get a full scale deflection on the galvanometer. DO NOT PEG OUT THE GALVANOMETER.

Smaller sets of nested coils and iron cores for mutual induction demonstrations are also available. 

The small 3 inch diameter coil is used with the small LED's that have been mounted on small copper coils.  Bring the coil near or over the LED's and observe the LED's light up.  

References:

  • J. A. McNeil, "The Metal Detector and Faraday's Law", TPT, Vol. 42, # 6, Sept. 2004,  p. 369.
  • H. Richard Crane,  "Smart Ignition Systems on Modern Cars",  TPT, Vol. 24, # 7, p. 438, October 1986.
  • Alfred Romer, "Faraday's Law Coils", AJP, Vol. 40, #7, July 1972, p. 1039.
  • Ek - 4, 7:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • B-220:  "Solenoids-Primary & Secondary",  DICK and RAE Physics Demo Notebook.
  • B-350:  "Iron Wire Core Increases Field",  DICK and RAE Physics Demo Notebook.
  • Rev. J, Lukin, "Metallic Contact", The Boy Engineers, 1901, p. 341.
  • Ron Hipschman, "Son of Transformer", Exploratorium Cookbook III, p. 152.1 - 152.3.
  • Ron Hipschman, "Induction", Exploratorium Cookbook III, p. 146.1 - 146.4.
  • W. Bolton, "Mutual Inductance", Book 4 - Electricity, Physics Experiments and Projects, 1968, p. 53.
  • C.J. Overbeck, R. R. Palmer, R. J. Stephenson, Marsh W. White, "Electromagnetic Induction", Cenco Selective Experiments in Physics, 1942, p.1-4.
  • The Queen Catalogues Vol. II, Catalogue of Physical Instruments, No. 5700, p. 105.
University of Maryland Physics Department QOTW Question #270
University of Maryland Physics Department QOTW Answer #270

Video Credit: Jonathan M. Sullivan-Wood

5K10.30 - Mutual Induction - Two Coils
5K10.30 - Induced Current using Two Coils