Internal resistance of vacuum diode
===================================

The internal resistance is generally equal to the current derivative of the voltage. For
a vacuum diode, it can be calculated if the diode parameter and the voltage between the
anode and cathode are known.

..
    TODO: find link

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

.. py:data:: internal_resistance

    Internal :attr:`~symplyphysics.symbols.electrodynamics.electrical_resistance` of the vacuum diode.

Symbol:
    :code:`R`

Latex:
    :math:`R`

Dimension:
    :code:`impedance`


.. py:data:: diode_constant

    :attr:`~symplyphysics.symbols.electrodynamics.diode_constant`.

Symbol:
    :code:`g`

Latex:
    :math:`g`

Dimension:
    :code:`current/voltage**(3/2)`


.. py:data:: voltage

    :attr:`~symplyphysics.symbols.electrodynamics.voltage` between cathode and anode.

Symbol:
    :code:`V`

Latex:
    :math:`V`

Dimension:
    :code:`voltage`


.. py:data:: law

    :code:`R = 2 / (3 * g * sqrt(V))`


    Latex:
        .. math::
            R = \frac{2}{3 g \sqrt{V}}