It is well known from the extant circuit theories that some important nonlinear circuit configurations cannot be modeled analytically. For resistive devices, the crux of this limitation is found to be the existence of non-ohmic resistances. Here, it is argued that the idea of nonlinear devices being always non-ohmic is misconceived and Ohm’s law should rather be applicable to all resistive nonlinear devices and circuits. Based on a recent research on modification of the general diode equation, an interpretation of the Ohm’s law is drawn so that it can be applied to nonlinear circuits as well. Additionally, the physics behind the important phenomenon of induced change in resistance, that enables the use of Ohm’s law in semiconducting junction devices, is explained and its inclusion is made in the equations for circuit design and analysis.

The general diode equation or the non-ideal diode equation is the foundation of circuit models of active devices for the past several decades. Apart from the effect of p-n junction, this equation also accounts for the series bulk resistance of a diode. Despite a reasonable agreement of the equation with measured IV characteristics, it is shown here that the equation is incompatible with basic theories of circuits and systems. Therefore, a modification in the equation is proposed to remove this incompatibility. This modified equation leads to a compact model of a p-n junction diode that has an excellent agreement with the measured IV characteristics.

In the past few years, a new type of circuit board, named here as active substrate board (ASB), was introduced over circuit applications of diodes. Unlike a traditional printed circuit board (PCB), an ASB has its substrate made of a semiconductor. The inability of the traditional integrated circuit (IC) technology to integrate wavelength dependent radio frequency (RF) components triggered the advent of ASBs. These boards draw desirable features from IC as well as PCB technologies. Unprecedented challenges came up in modeling the different devices fabricated on an ASB owing to their large sizes and the presence of wideband microwaves. So far, modeling the effect of large sizes and ambient microwaves on DC bias of diodes have not been considered in scientific literature. Furthermore, the state of the art numerical simulators are unable to imitate the behavior of such diodes observed over measurements. Here, a semi-analytical, circuit model of distributed diodes on ASB is presented that is fairly accurate in predicting the actual behavior of the diodes. The model also opines a novel phenomenon where microwaves affect the DC characteristics of diodes with added resistances.