Endevco® Model 7265A Series Low Mass Piezoresistive Shock Accelerometers

Product catalog summary

Overview: The Endevco model 7265A series is a line of piezoresistive accelerometers designed for applications such as flutter testing and biomedical motion studies. These accelerometers are characterized by their low mass (6 grams), high sensitivity, and good low-frequency response, making them suitable for scenarios requiring minimal mass loading.

Specifications: The series includes two models: 7265A with a sensitivity of 5 mV/g and a full scale of 100 g, and 7265A-HS with a sensitivity of 25 mV/g and a full scale of 20 g. Both models feature a full-bridge circuit with two PIEZITE® P-11 silicon gages and two fixed resistors, providing a low impedance output of 500 mV full scale with 10 Vdc excitation.

Features: Key features include viscous damping to extend the high-frequency range and reduce spurious excitations, mechanical stops for overrange shock protection, and a small size for minimal interference in motion studies. The accelerometers are damped, have a DC response, and are suitable for motion studies.

Performance: The 7265A model has an amplitude response of 0 to 800 Hz, while the 7265A-HS model ranges from 0 to 500 Hz. Both models have a damping ratio of 0.707 and a maximum non-linearity and hysteresis of ±2% of the reading. The mounted resonance frequency is 2700 Hz for the 7265A and 1400 Hz for the 7265A-HS.

Environmental and Physical Characteristics: The accelerometers are made from anodized aluminum alloy and are hermetically sealed to be unaffected by humidity and altitude. They can operate in temperatures ranging from 0˚F to 150˚F and can withstand static acceleration limits of 2000 g and sinusoidal vibration up to 1000 g for the 7265A and 200 g for the 7265A-HS.

Electrical Characteristics: The accelerometers require an excitation voltage of 10 Vdc, with a maximum of 15 Vdc. They have an input resistance of 750 ohms and an output resistance of 900 ohms, with fixed resistors at 500 ohms ±1%.

Accessories and Calibration: Standard accessories include an Allen wrench, flat washers, and socket head cap screws. Optional accessories include a shielded cable and a triaxial mounting block. Calibration data is provided, and Endevco offers factory calibration services for maintaining precision and accuracy.

Notes: The document emphasizes the importance of maintaining the safety sleeve on the unit when not in use and highlights the availability of tighter specifications upon special order. Endevco reserves the right to modify specifications without notice to ensure product reliability.

Catalog excerpts

Endevco® Model 7265A Series Low Mass Piezoresistive Shock Accelerometers-1

Model 7265A/A-HS Piezoresistive accelerometer Features • Small size • 20 and 100 g full scale • Damped • DC response • Motion studies The Endevco® model 7265A series, with sensitivity up to 25 mV/g, is a family of very low mass (6 gram), piezoresistive accelerometers designed for flutter testing, biomedical motion studies, and similar applications requiring high sensitivity, good low frequency response and minimum mass loading. The model 7265A series has viscous damping to extend the useful high frequency range and to reduce the effects of spurious high frequency excitation. Mechanical stops prevent damage when the transducer is subjected to overrange shock. The model 7265A series utilizes two of Endevco’s PIEZITE® P-11 silicon gages and two fixed resistors in a full-bridge circuit. This configuration provides a low impedance output of 500 mV full scale with 10 Vdc excitation. The model 7265A has a sensitivity of 5 mV/g and a full scale of 100 g. The model 7265A-HS (high sensitivity) has a very high sensitivity of 25 mV/g with a full scale of 20 g. Endevco model 136 three-channel system, model 4430A or OASIS 2000 computer-controlled system are recommended as signal conditioner and power supply. CENTER OF SEISMIC MASS .105 (2.67) DIA CABLE 4 COND #32 AWG S.P.C., TEFLON INS, BRAIDED S.P.C., SHIELD, SILICONE RUBBER OUTER JACKET ACCELERATION IN THIS DIRECTION CAUSES POSITIVE OUTPUT. HOUSING CASE CABLE SHIELD SCHEMATIC STANDARD TOLERANCE INCHES (MILLIMETERS) .XX = +/- .03 (.X = +/- .8) .XXX = +/- .010 (.XX = +/- .25)

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Endevco® Model 7265A Series Low Mass Piezoresistive Shock Accelerometers-2

Model 7265A/A-HS Piezoresistive accelerometer Specifications Range g pk Sensitivity (at 100 Hz) mV/g typ (Min) Amplitude response [1] ±5% Hz Mounted resonance frequency [1] Hz Damping ratio [2] Non-linearity and hysteresis (% of reading, to full range) % Max Transverse sensitivity % Max Zero measurand output [3] mV Max Thermal zero shift from 0 to 150˚F (-18˚C to +66˚C) mV Max Thermal sensitivity shift from 0 to 150˚F (-18˚C to +66˚C) % Typ Warm-up time Minutes max Electrical Excitation [4] [5] Input resistance [4] [6] Output resistance [4] [6] Fixed resistors Insulation resistance 10.0 Vdc,...

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