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seebeck:start [2011/04/26 00:15] rachelseebeck:start [2020/03/06 09:04] (current) – external edit 127.0.0.1
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 ==== About Our Experiment ==== ==== About Our Experiment ====
-We use a cryochamber to measure the Seebeck coefficient from temperatures ranging 30-300 K.  A thin-film semiconductor is clamped down between two copper blocks within the chamber; to ensure electrical contact between the copper and the sample, small indium strips are laid down between them.  A K-type thermocouple connected to the "cold" block and electrically insulated from it records the temperature of the chamber.  A 19 Ω resistor resides in the "hot" block, electrically insulated from the copper, and provides a small (3-5 K) temperature gradient across the sample once a current is passed through it.  +We use a cryochamber to measure the Seebeck coefficient from temperatures ranging 30-300 K.  A thin-film semiconductor is clamped down between two copper blocks within the chamber; to ensure electrical contact between the copper and the sample, small indium strips are laid down between them.  A K-type thermocouple (chromel-alumel) connected to the "cold" block, but electrically insulated from itrecords the temperature of the chamber.  A K-type differential thermocouple attached to both blocks (in thermal contact but not electrical) yields the temperature gradient between the blocks.  A 19 Ω resistor resides in the "hot" block, electrically insulated from the copper, and provides a small (3-5 K) temperature gradient across the sample once a current is passed through it.  
  
 Once the current is turned off, the voltage produced by the sample and the temperature gradient between the two copper blocks are measured.  Measurements are taken until both the potential across the sample and the temperature gradient between the blocks return to 0 mV.  The potential is plotted against the temperature gradient and the slope of the line yields the Seebeck coefficient. Once the current is turned off, the voltage produced by the sample and the temperature gradient between the two copper blocks are measured.  Measurements are taken until both the potential across the sample and the temperature gradient between the blocks return to 0 mV.  The potential is plotted against the temperature gradient and the slope of the line yields the Seebeck coefficient.
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   * [[seebeck:troubleshooting:|Troubleshooting]]   * [[seebeck:troubleshooting:|Troubleshooting]]
  
 +====Papers to get you started:====
 + [[http://www.omega.com/temperature/Z/zsection.asp|Omega thermocouple reference]]
 +
 +In particular this one[[http://www.omega.com/temperature/Z/pdf/z019-020.pdf|Introduction to Practical Temperature Measurements]]

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