Measurement of the electron charge $q_e$ using Schottky noise. Problem of the 6-th Experimental Physics Olympiad. Sofia 8 December 2018
Eur. J. Phys. 39 065202 (2018); Bulgarian Physics Education vol. 7, book 1, 68-79 (2019), (in Bulgarian) Several consecutive experiments are described with a printed circuit board PCB set-up, especially designed for these experiments. Doing the consecutive experimental tasks opens up possibility to...
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Main Authors | , , , , , , , , , , , , , , , , |
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Format | Journal Article |
Language | English |
Published |
15.03.2017
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Subjects | |
Online Access | Get full text |
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Summary: | Eur. J. Phys. 39 065202 (2018); Bulgarian Physics Education vol.
7, book 1, 68-79 (2019), (in Bulgarian) Several consecutive experiments are described with a printed circuit board
PCB set-up, especially designed for these experiments. Doing the consecutive
experimental tasks opens up possibility to determine the value of electron
charge $q_e.$ The fluctuations of the voltage $U(t)$ should be measured for
different illuminations of a photodiode. The voltage is amplified 1 million
times $Y=10^6$. The amplified voltage $YU(t)$ is applied to the device, which
gives the result of the value of the time averaged square of the voltage
$U_\mathrm{S}=\left<(Y U(t))^2\right>/U_0$. This voltage $U_\mathrm{S}$ is
measured with a multimeter. The series of measurements gives the possibility to
determine the $q_e$ using the well known Schottky formula for the spectral
density of the current noise $(I^2)_f=2q_e\left<I\right>.$ For the junior high
school students, the basic problem is to analyze the analog squaring. Students'
work is separated and graded in four categories S, M, L, XL divided by age of
students. For the last XL categories, the tasks contain problems oriented to
physics university education program and include theoretical research of the
PCB set-up as an engineering device. This is the problem of EPO6, December 2018
``Day of the Charge'' considered. EPO6 is organized by Sofia branch of Union of
physicists in Bulgaria in cooperation with Faculty of physics of Sofia
University and Society of Physicists of Republic of Macedonia. |
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DOI: | 10.48550/arxiv.1703.05224 |