Probe microphone takes centre stage at show

14th August 2014

Mick Elliott

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Datasheet

PCB Piezotronics will show accelerometers, probe microphones and sensors at the Sensors & Instrumentation exhibition, NEC, Birmingham, UK (Sept 30-Oct 1). A range of PCB ICP low temperature coefficient single and triaxial accelerometers – series 339A – designed for powertrain development and powertrain noise, vibration and harshness (NVH) applications will be shown along with an innovative charge output accelerometer capable of making vibration measurements in extreme heat environments up to 650°C.

The accelerometers are designed with a low temperature coefficient, wide operating temperature range and good broadband measurement resolution, all desirable characteristics when used in powertrain development and powertrain NVH applications or any vibration measurement requiring tight control of amplitude sensitivity over a wide thermal gradient.

With a temperature coefficient as low as 0.009%/°C, these titanium housed and hermetically sealed units have a 10 or 50mV/g sensitivity, a measurement frequency to 10kHz and an operating temperature range from -73 to +163°C. Innovations in high temperature accelerometer technology for gas turbine monitoring have led to the development of the series 357D90, a charge output sensor that enables vibration measurement in extreme heat environments up to 650°C.

With sensitivity of 5pC/g ±10%, measurement range of ±1000g peak and frequency range of 2.5kHz, the sensor is ideal for use in the most demanding gas turbine measurement and monitoring applications. PCB’s latest probe microphone – model 377B26 – is designed for R&D engineers who need to measure sound pressure in confined areas.

The probe tip diameter is extremely small measuring 1.3mm which enables white goods, telephone, headphone, loudspeaker and musical instrument manufacturers to make measurements in small, confined and difficult-to-access areas that cannot be accessed using traditional microphones, which are typically larger.

The small size of the probe tip also allows near field measurements with minimal disturbance of the sound field. This enables more accurate test results. The probe microphone comprises four components: pre-polarised microphone, preamplifier, housing and several probe tips of different lengths. The components work together to provide a maximum operating temperature of 800°C, much greater than traditional test & measurement microphones. Other microphones on show will be models 378B02, 377B02 and 130E20. Manufacturing process improvements have enabled PCB Piezotronics to reduce prices on these models.