Sensitivity is an important indicator to measure the sensitivity of the output of physical instrument to the variation of measured parameters. The research of sensitivity can enhance the understanding of the network structure and circuit principle inside the instrument, especially further improve the sensitivity of the electrical measuring instrument. In this paper, an example of sensitivity analysis, including problem formulation, problem analysis, problem discussion and problem solution, was presented. Finally, it proved that the essence of circuit principle, the applicable range of solution methods and the diversity of analysis methods were needed to analyze the circuit sensitivity with matrix form of incremental network approach.