This paper studies the method of auto balancing bridge to precisely measure inductance L, capacitance C, resistance R(namely LCR)by measuring the high and low terminal vector voltages.

With the advantages of good stability, high precision and good electromagnetic resistance, the Fabry-Perot(F-P) strain sensor get increasing applications in the bridge structure status monitoring.

Three methods on measuring high resistance improved electric bridge method, voltage method, and comparative method are introduced in the article.