Search results
Results from the WOW.Com Content Network
The charge signals at the input of a charge amplifier can be as low as some fC (FemtoCoulomb = 10 −15 C). A parasitic effect of common coaxial sensor cables is a charge shift when the cable is bent. Even slight cable motion may produce considerable charge signals which cannot be distinguished from the sensor signal.
Piezoelectric sensors which do not possess IEPE electronics, meaning with charge output, remain reserved for applications where lowest frequencies, high operating temperatures, an extremely large dynamic range, very energy saving operation or extremely small design is required.
The cross-section of a piezoelectric accelerometer. The word piezoelectric finds its roots in the Greek word piezein, which means to squeeze or press. When a physical force is exerted on the accelerometer, the seismic mass loads the piezoelectric element according to Newton's second law of motion (=). The force exerted on the piezoelectric ...
When the accelerometer experiences a motion, the invariant seismic mass loads the elements according to Newton's second law of motion =. The main difference in working principle between these two cases is the way they apply forces to the sensing elements.
An accelerometer measures proper acceleration, which is the acceleration it experiences relative to freefall and is the acceleration felt by people and objects. [2] Put another way, at any point in spacetime the equivalence principle guarantees the existence of a local inertial frame, and an accelerometer measures the acceleration relative to that frame. [4]
An accelerograph can be referred to as a strong-motion instrument or seismograph, or simply an earthquake accelerometer.They are usually constructed as a self-contained box, which previously included a paper or film recorder [1] (an analogue instrument) but now they often record directly on digital media and then the data is transmitted via the Internet.
Actigraphs have a number of different ways of accumulating the values from the accelerometer in memory. ZCM (zero crossing mode) counts the number of times the accelerometer waveform crosses 0 for each time period. PIM (proportional integral mode) measures the area under the curve, and adds that size for each time period.
Also apophthegm. A terse, pithy saying, akin to a proverb, maxim, or aphorism. aposiopesis A rhetorical device in which speech is broken off abruptly and the sentence is left unfinished. apostrophe A figure of speech in which a speaker breaks off from addressing the audience (e.g., in a play) and directs speech to a third party such as an opposing litigant or some other individual, sometimes ...