Extensive studies on the discharge current of a 50-kHz argon glow discharge in a parallel-plate reactor has led to a model that is able to describe the discharge in a wide range of pressures and powers for the evaluation of plasma parameters. The network simulation program PSPICE can be used to simulate the model in a way easily adapted to other plasma reactors as well. This may lead to a new plasma diagnostic method that does not require a complicated setup. The behavior of the discharge current can also be used for numerical simulations of the self-bias voltage in capacitively coupled plasma reactors. The influence of power and pressure can be integrated and allows an estimation of the self-bias for given reactor geometries and process parameters.