Comperator
==========

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   * - .. image:: ../../images/computing_elements/comparator.png
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     - .. image:: ../../images/computing_elements/comparator_symbol.png
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  	      :alt: Alternative text
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   * - THAT comperatorunit)
     - Comperator symbol
     
The **comparator** is a logic element which compares the signals **a** and **b**, at the THAT-comperator this panels are found on the left side, and gives a corresponding output, dependent on **a** and **b**.

The middle column (panel >0 and <0) holds the inputs given to the **OUT** panels.

**If a + b is smaller than zero, the input at <0 is given to the output.**

**If a + b is greater than zero, the input at >0 is given to the output.**

Comperators are very usefull or even necessary for many applications, for example when simulating a jumping ball, the prompt sign change in the movement direction can easily be modeled with a comperator.