Hot Carbon Fiber Acoustic Vector Sensor and Flowmeter

In this paper, a new type of hot wire acoustic vector sensor based on Polyacrylonitrile base carbon fiber, as a sensing element is presented. The vector sensor employs two suspended carbon fiber with micro size diameter and millimeter length as a pair of hot wires that are close together with hundreds of micron separation. Resistance-Temperature curve shows that the temperature coefficient of resistance is negative for carbon fibers. Sensor response to air flow, directivity index, frequency response and sensitivity of the sensor in two different bias voltage have been measured.