5A22.93 - Electroscope - FET

Code Number:
5A22.93
Demo Title:
Electroscope - FET
Condition:
Good
Principle:
Electrostatic Deflection & Detection
Area of Study:
Electricity & Magnetism
Equipment:
FET Electroscope with 9 volt battery, positive and negative charging rods.
Procedure:

Video Credit: Jonathan M. Sullivan-Wood.

Plug a 9 volt battery into the battery clip of the FET electroscope.  Bring a negative charge near the sensing gate and the red LED will come on. A positive charge will make the green LED come on.

References:
  • Hina Morishige, Tetsuya Kato, "Triboelectric Series Using a Simple Charge Sign Checker", TPT, Vol. 60, #8, Nov. 2022, p. 667.
  • James Lincoln, "Devices that Can Identify Positive vs. Negative Charge", TPT, Vol. 55, #7, Oct. 2017, p. 440.
  • Xiang Yong Chen and Xing Wang, "Detecting the Polarity of an Electric Charge", TPT, Vol. 37, #6, Sept. 1999, p. 344.
  • "The Little Shop Physics: Static Sensor", TPT, Vol. 34, #8, Nov. 1996, p. 517.
  • William R. Gregg, "Three Inexpensive High - Voltage Electricity Demonstrations", TPT, Vol. 30, #7, Oct. 1992, p. 400.
  • Mihai P. Dinca, "Charge Sniffer for Electrostatics Demonstrations", AJP, Vol. 79, #2, Feb. 2011, p. 217.
  • Salvatore Ganci, "An Electroscope Discriminating the Sign of Charges", AJP, Vol. 62, #5, May 1994, p. 474.
  • Jodi and Roy McCullough, "Static Electricity", The Role of Toys in Teaching Physics, p. 4.48.
  • Gary Benoit, "A New Device for Studying Electric Fields", Apparatus for Teaching Physics, p. 151, Edited by Karl Mamola.
  • Robert D. Meyers, "An Easy-to-assemble Electroscope", The Science Teacher 28, 34, 1990.
  • Dick Heckathorn, "Modification to Electroscope",
  • Electroscope-5.jpg.
  • Jay Zimmerman, "Physics Demonstration Ideas".
  • William Beatty, "Inexpensive FET Electrometer", PIRA Newsletter,  Vol. 9, No. 3.
  • Tom Petruzzellis, "Electrostatic Fundamentals", Electronic Sensors for the Evil Genius, p. 195.
  • G. Jordan Maclay, "Electrical Engineering Experiment #2: Field Effect Transistors", Keithley Instruments Series II.
  • Forrest M. Mims III, "Electronic Electroscope", Science and Communication Circuits & Projects, p. 11.


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.