Template:Example:T-H: Difference between revisions

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::<math>\begin{align}
::<math>\begin{align}
   & \widehat{\beta }= & 5.87439512 \\  
   & \widehat{\beta }= & 5.874395 \\  
  &  &  \\  
  &  &  \\  
  & \widehat{A}= & 0.0000597 \\  
  & \widehat{A}= & 0.000060 \\  
  &  &  \\  
  &  &  \\  
  & \widehat{b}= & 0.2805985 \\  
  & \widehat{b}= & 0.280599 \\  
  &  &  \\  
  &  &  \\  
  & \widehat{\phi }= & 5630.329851   
  & \widehat{\phi }= & 5630.329851   

Revision as of 22:17, 16 February 2012

T-H Example


The following data were collected after testing twelve electronic devices at different temperature and humidity conditions:

Ex1chp9.gif



Using ALTA, the following results were obtained:


[math]\displaystyle{ \begin{align} & \widehat{\beta }= & 5.874395 \\ & & \\ & \widehat{A}= & 0.000060 \\ & & \\ & \widehat{b}= & 0.280599 \\ & & \\ & \widehat{\phi }= & 5630.329851 \end{align} }[/math]


A probability plot for the entered data is shown next.


Probability plots at the tested combinations.



Note that three lines are plotted because there are three combinations of stresses, namely, (398K, 0.4), (378K, 0.8) and (378K, 0.4).


Given the use stress levels, time estimates can be obtained for specified probability. A Life vs. Stress plot can be obtained if one of the stresses is kept constant. For example, the following picture is a Life vs. Humidity plot at a constant temperature of 338K.

Life vs. Humidity plot with temperature fixed at 338K.