Hitech Sensors Limited
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MEMS piezoresistive accelerometers are used as sensing components. Piezoresistive accelerometers consist of strain gauges that measure stress in the springs supporting the mass. Stress can be directly related to the magnitude and rate of displacement of the mass, and therefore to acceleration. These devices can sense acceleration over a wide frequency range: from near DC to 13kHz. With proper design, it can withstand overshocks up to 10,000g. Of course, its dynamic range (range) is somewhat narrow (1000g, error less than 1%). For many applications, overshock is a critical indicator. Piezoresistive accelerometers, which consist of discrete, epoxy-bonded strain gauges, have a poor output temperature coefficient. Because they are manufactured separately, the strain gauges require separate thermal testing and parameter matching. This problem is virtually eliminated in modern sensors that use micromachining technology on silicon wafers.
An example of a wide dynamic range solid-state accelerometer is from Endevco/PCB. This tiny sensor is made of three layers of silicon. The inner or core layer contains the inertial mass and the elastic hinge. The mass is suspended within an etched frame by a hinge, and there are piezoresistive strain gauges on each side of the hinge. The strain gauges detect movement associated with the hinge. Two outer layers, a base and a cover, protect the moving parts from external contamination. Both outer layers have concave walls that allow the inertial mass to move freely. This sensor has several important features. One of them is that the sensing axis lies in the plane of the silicon wafer, as opposed to many other designs where the axis is perpendicular to the wafer. All components of the sensor are manufactured from a single silicon crystal, ensuring mechanical integrity and reliability. When acceleration is applied along the sensing axis, the inertial mass rotates around the hinge. The rotation of the mass generates compressive stress on one strain gauge on each side of the hinge and tensile stress on the other. Because the strain gauges are very short, even small displacements produce large resistance changes. To adjust the zero balance of the piezoresistive bridge, five adjustment resistors are configured in the same chip.
In order to prevent the accelerometer used in high impact environments such as explosions and metal collisions from resonating, its resonant frequency should be high enough. For example, the resonant frequency of the MEMS silicon-based piezoresistive accelerometer (7270A-200K) designed by Endevco can reach 1.2 MHz (amplitude can reach 200,000 G);
Our HTS-417 High impact PR MEMS accelerometer is an alternative of 7270A Piezoresistive MEMS Shock Accelerometers of Endevco, its features with high shock 100000g, big range ±60000g, high sensitivity 2 µV/g and high resonant frequency response etc.
For more details, pls. kindly contact us as following.
Hitech Sensors Limited
Address: Room 412,Unit 2,Block B, Shenglong Plaza, Weiyang Road , Xi'an ,China
Web: http://hitechsensors.net/
Email: info@hitechsensors.net
An example of a wide dynamic range solid-state accelerometer is from Endevco/PCB. This tiny sensor is made of three layers of silicon. The inner or core layer contains the inertial mass and the elastic hinge. The mass is suspended within an etched frame by a hinge, and there are piezoresistive strain gauges on each side of the hinge. The strain gauges detect movement associated with the hinge. Two outer layers, a base and a cover, protect the moving parts from external contamination. Both outer layers have concave walls that allow the inertial mass to move freely. This sensor has several important features. One of them is that the sensing axis lies in the plane of the silicon wafer, as opposed to many other designs where the axis is perpendicular to the wafer. All components of the sensor are manufactured from a single silicon crystal, ensuring mechanical integrity and reliability. When acceleration is applied along the sensing axis, the inertial mass rotates around the hinge. The rotation of the mass generates compressive stress on one strain gauge on each side of the hinge and tensile stress on the other. Because the strain gauges are very short, even small displacements produce large resistance changes. To adjust the zero balance of the piezoresistive bridge, five adjustment resistors are configured in the same chip.
In order to prevent the accelerometer used in high impact environments such as explosions and metal collisions from resonating, its resonant frequency should be high enough. For example, the resonant frequency of the MEMS silicon-based piezoresistive accelerometer (7270A-200K) designed by Endevco can reach 1.2 MHz (amplitude can reach 200,000 G);
Our HTS-417 High impact PR MEMS accelerometer is an alternative of 7270A Piezoresistive MEMS Shock Accelerometers of Endevco, its features with high shock 100000g, big range ±60000g, high sensitivity 2 µV/g and high resonant frequency response etc.
For more details, pls. kindly contact us as following.
Hitech Sensors Limited
Address: Room 412,Unit 2,Block B, Shenglong Plaza, Weiyang Road , Xi'an ,China
Web: http://hitechsensors.net/
Email: info@hitechsensors.net
