Research on method of analog circuit fault diagnosis based on voltage sensitivity ratio

For the tolerant and test nodes to be limited in the actual circuit, a theorem had been proved that the ratio of voltage variation at different nodes equal to the ratio of voltage sensitivity at corresponding nodes when an element parameter changes in the linear circuits. A new method had been put forward for the analog circuit fault diagnosis based on the theorem, and the Method is extended to circuits with tolerance. Expressions of node voltage sensitivity ratio region in the condition with tolerance problem are presented. The theory analysis and the experimental result shows that the algorithm of the new method is effective hard-fault and soft-fault, has simple construction and high calculating speed, needs littler nodes. The method can raise the accuracy of circuit fault diagnosis when the test nodes are limited. It is very practical for the large-scale linear analog circuit fault diagnosis and testing.