Direct permeability coefficient of triode with flat electrodes
==============================================================

The coefficient of direct permeability of the grid characterizes its shielding effect
and shows how much the electrostatic field of the anode is weaker than the grid field
affects the cathode area. There is no general formula for this coefficient for an
arbitrary electrode configuration, but there are formulas for special cases. One such
case is a triode with flat electrodes.

..
    TODO: find link

.. py:currentmodule:: symplyphysics.laws.electricity.circuits.diodes.direct_permeability_coefficient_for_triode_with_flat_electrodes

.. py:data:: direct_permeability_coefficient

    Direct permeability coefficient of the grid.

Symbol:
    :code:`D`

Latex:
    :math:`D`

Dimension:
    :code:`dimensionless`


.. py:data:: first_tabular_coefficient

    First tabular coefficient.

Symbol:
    :code:`C_1`

Latex:
    :math:`C_{1}`

Dimension:
    :code:`dimensionless`


.. py:data:: grid_step

    Grid step, or :attr:`~symplyphysics.symbols.classical_mechanics.euclidean_distance` between grid wires.

Symbol:
    :code:`d_0`

Latex:
    :math:`d_{0}`

Dimension:
    :code:`length`


.. py:data:: distance

    :attr:`~symplyphysics.symbols.classical_mechanics.euclidean_distance` between anode and grid.

Symbol:
    :code:`d`

Latex:
    :math:`d`

Dimension:
    :code:`length`


.. py:data:: second_tabular_coefficient

    Second tabular coefficient.

Symbol:
    :code:`C_2`

Latex:
    :math:`C_{2}`

Dimension:
    :code:`dimensionless`


.. py:data:: law

    :code:`D = C_1 * d_0 / (d * C_2)`


    Latex:
        .. math::
            D = \frac{C_{1} d_{0}}{d C_{2}}