Circuits of Resistors, Diodes and Sources: Topological Conditions Sufficient to Define the State of a Diode Let  N  be a circuit composed of a finite number of positive linear resistors, ideal diodes, and independent voltage and current sources with positive values. In this paper, we consider the problem to determine, without any numerical computation, the state of a diode of  N . We propose two set of topological conditions xe2x80x93 those of the second set being more intuitive and less cumbersome, but also less powerful, than those of the first set xe2x80x93 such that, when verified by a diode of  N , the state of the diode is determined and also independent of the positive values of the resistances and sources. Our results may simplify, sometimes dramatically, the usual trialanderror procedure to find the solutions of  N .

Systematic Construction of Resistor Ladder Network for Nary DACs This paper describes a systematic configuration method of resistor ladder networks for Nary DACs, by generalizing the configuration of the conventional R2R DAC. Resistor networks divide the current at each node with its combined resistor ratio; the current flowing into each node of the resistor ladder is weighted with a nonbinary ratio. Also using several unit current sources at each node, configuration of nonbinary weighted DACs (such as ternary and quaternary weighted ones) can be derived. We have verified the operation of these resistor network DACs by SPICE simulations, and discuss their pros and cons as well as possible applications.