def calc_delta_capacitance_ratio(capacitance_doublelayer, capacitance_dielectric):
    """
    Ratio of the double layer to dielectric capacitance
    units: ~
    Notes:
        Squires, 2010   -   "Ratio of the double layer to dielectric capacitance"
        Adjari, 2006    -   "Surface capacitance ratio"
            --> At larger potentials the Debye layer capacitance becomes very large and,
            --> total capacitance is dominated by the Stern layer only.
            --> Capacitance ratios: C_total < C_debye layer < C_dielectric layer
    """
    delta = capacitance_doublelayer / capacitance_dielectric
    return delta