Difference between revisions of "Permittivity and Permeability of Materials Obstacle Course"
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# Place three samples (air, Teflon, glass) between the aligned and polished ends of two 3/8" diameter, 1/2" lengths of 6061 Al rods (as shown at right). <math>d</math> should be on the order of 1 mm. Measure the capacitances and, from the known surface area <math>A</math> and spacing <math>d</math>, determine the material's relative permittivity. <math>C = \epsilon_r \epsilon_0 \frac{A}{d}</math>. | # Place three samples (air, Teflon, glass) between the aligned and polished ends of two 3/8" diameter, 1/2" lengths of 6061 Al rods (as shown at right). <math>d</math> should be on the order of 1 mm. Measure the capacitances and, from the known surface area <math>A</math> and spacing <math>d</math>, determine the material's relative permittivity. <math>C = \epsilon_r \epsilon_0 \frac{A}{d}</math>. | ||
# How do your measured permittivity values compare to standard reference values? | # How do your measured permittivity values compare to standard reference values? | ||
| + | <math>\epsilon_r</math>(air): 1.000536<br> | ||
| + | <math>\epsilon_r</math>(Teflon): 2.1<br> | ||
| + | <math>\epsilon_r</math>(glass): 3.7-10<br> | ||
Revision as of 14:09, 16 May 2018
PAGE UNDER CONSTRUCTION
Contents
Permanent Materials
- 6061 3/8" Al rod stock
- Teflon
- Glass microscope slide
- HP Signal Generator (DC-1 GHz)
- Oscilloscope (at least 1GHz bandwidth)
- Miscellaneous electrical components
Materials to Borrow When Necessary
- Milling machine
- Lathe
Activities
Reading
- Read the Wikipedia articles on permittivity and permeability. With the help of the instructor or TA try to achieve a physical understanding of just what the permittivity and permeability mean in a bulk material.
- Read the first three sections of this paper (pages 1-27). Pay particular attention to the permittivity (Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \epsilon} ) / capacitance and permeability (Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \mu} ) / inductance associations.
Permittivity of a Lossless Material From a Capacitance Measurement
- Place three samples (air, Teflon, glass) between the aligned and polished ends of two 3/8" diameter, 1/2" lengths of 6061 Al rods (as shown at right). Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle d} should be on the order of 1 mm. Measure the capacitances and, from the known surface area Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} and spacing Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle d} , determine the material's relative permittivity. Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle C = \epsilon_r \epsilon_0 \frac{A}{d}} .
- How do your measured permittivity values compare to standard reference values?
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \epsilon_r}
(air): 1.000536
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \epsilon_r}
(Teflon): 2.1
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \epsilon_r}
(glass): 3.7-10
