A novel micromechanical bridge shape voltage-controlled oscillator with high Q value was fabricated. The core of this class of oscillators is an electrothermally excited and piezoresistively detected micromechanical bridge resonator. Its resonance frequency can be adjusted by changing the DC bias voltage applied on the excitation resistor. Theoretical analysis and experiment data show that its resonance frequency is linear with the square of the DC bias voltage. The kind of VCO has the advantages of good linearity, wide adjustable frequency range and high quality factor Q. (C) 2004 Elsevier Ltd. All rights reserved.