US Patent 7814795 Dual mode measurement system with quartz crystal microbalance

A dual mode measurement system with quartz crystal microbalance (QCM) is provided, which includes a quartz sensing component, a first measurement circuit, a second measurement circuit and a switch unit. When the first measurement circuit is selected through the switch unit, the first measurement circuit and the quartz sensing component form an oscillation circuit and output a resonance signal. When the second measurement circuit is selected through the switch unit, the second measurement circuit outputs a frequency scanning signal to scan the quartz sensing component, so as to output an impedance sensing signal.