**Nomenclature**


ZCS – Zero current switching

A – Cell active area (cm2)

C – Equivalent electrical capacitance (F)

ENernst – Thermodynamic potential

Jmax – Maximum current density (A/cm2)

n – Number of cells in stack

PO2 – Oxygen partial pressure (atm)

PH2 – Hydrogen partial pressure (atm)

RC – Contact resistance (Ω)

RM – Equivalent membrane resistance (Ω)

T – Cell operating temperature (K)

Vact – Activation voltage drop (V)

Vohmic – Ohmic voltage drop (V)

Vcon – Concentration voltage (V)

ξi, ψ – Parametric coefficients

λ – Membrane thickness (μm)

fr – Resonant frequency (Hz)

wr – angular frequency (rad/s)

Zr – Resonant impedance (Ω)

Lr – Resonant tank inductor (H)

Cr – Resonant tank capacitor (F)

Q – Quality factor
