This paper reports transient equivalent circuit analysis for self-induced oscillation of micromechanical resonator using a novel component model of an electrostatic comb transducer. The model with built-in displacement detection can analyze dc operating points which depends on both on electrical and mechanical biases. By using the proposed model, we analyzed the bias voltage dependency of oscillation risetime and amplitude. From comparing the analysis and measurement of start-up transient response of an SOG (silicon-on-glass) resonator, we showed the proposed comb model facilitate designing and estimate oscillator performance. © 2011 IEEE.