Bistable smectic-A (SmA) liquid crystal display (LCD) is one of the most promising devices for smart glass applications due to long-term bistability, low haze at clear state, low transmittance at scatter state and low power consumption. The need of a good simulation model for an LCD becomes apparent during the design of driving system. Liquid crystal (LC) capacitance is critical in the simulation of LCD pixels and is voltage dependent due to the crystal characteristics. Bistable smectic-A LC capacitance model is introduced in the paper. The study describes the most relevant conclusions obtained from the measurements of electric properties of bistable SmA LCD samples and electric equivalent circuit characterization.