The designed quartz crystal microbalance（ QCM） instrument is to measure biochemical reactions of trace substances in liquid. The circuits system is designed according to requirements of liquid phase QCM biosensor

including power supply unit

signal excitation and receiving unit

temperature control parts. the liquid phase QCM biosensor makes Microchip MCU as core of circuit system

which can realize the stimulation of the quartz crystal and the detection of the frequency

the acquisition and control of the temperature and so on. Upper PC test results demonstrate that real temperature control precision is ± 0. 2 ℃ and the optimal resonant frequency can be detected smoothly

which prove that the system can reach the expected requirments well.