摘要 |
<p>In a combined seat heater and capacitive occupancy sensor, the present invention proposes to perform two measurements with two different frequencies. In a first step, the carrier frequency is set to a first known carrier frequency, the complex current through inductance and unknown capacitance and complex drive voltage are measured. In a second step, the carrier frequency is set to a second known carrier frequency, the complex current through inductance and unknown capacitance and complex drive voltage are measured. The measured complex values are used in a formula which yields the unknown capacitance.</p> |