2009 Advanced Laboratories Conference Abstract Detail Page
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||Noise Fundamentals, where noise is the signal
||The measurement and theoretical examination of noise is an important and underrepresented topic in the advanced laboratory. Noise is inherent in all measurements and sets the lower limit of any physical measurement. Noise can be used to determine fundamental constants. The Johnson voltage noise from a resistor (vn^2 = 4RkT) gives a measure of the Boltzmann constant (k) if the resistance (R) and temperature (T) are known. The charge of the electron (e) can be determined from a DC current (I) with full shot noise (in^2 = 2eI).
The apparatus that will be demonstrated can be used to measure the Johnson noise from resistors in the range from 10 ohm to 10 M ohm, over a calibrated frequency range of 3 to 100 kHz and temperatures from 77 to 373 K. Shot noise is measured in currents ranging from 10 nA to 1 mA. The currents can be derived from a variety of sources: a photodiode illuminated by an incandescent light bulb or an LED; a forward biased PN junction; a diode connected bipolar junction transistor; or from a zener diode. Some of the experimental subtleties of noise measurement will be presented, especially the effect of capacitance.
Download the Contributed Poster
||Session IX - Effective Experiments Poster Session
2495 Main Street - Suite 409
David Van Baak
Department of Physics and Astronomy
dvanbaak -at- calvin.edu