Constants
~~~~~~~~~

The following mathematical and physical constants are available through the ``h`` module: 

::

    h.PI        3.14159265358979323846
    
    h.E         2.71828182845904523536
    
    h.GAMMA     0.57721566490153286060 (Euler)
    
    h.DEG       57.29577951308232087680 (deg/radian)
    
    h.PHI       1.61803398874989484820 (golden ratio)
    
    h.FARADAY   96484.56 (coulombs/mole)
    
    h.R         8.31441 (molar gas constant, joules/mole/deg-K)


.. warning::
    Constants are not treated specially by the interpreter and 
    may be changed with assignment statements. 
     
    The FARADAY is a bit different than the faraday of the units database. 
    The faraday in a :file:`.mod` mechanism is 96520.