The temperature effect on the gain of charge amplifiers

• Autor(a) principal: Ripper, Gustavo Palmeira
• Data de Publicação: 2005
• Outros Autores: Dias, Ronaldo da Silva, Garcia, Guilherme de Andrade, Zindeluk, Moysés
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional do INMETRO
• Texto Completo: http://hdl.handle.net/10926/788

ABSTRACT: Calibrations of accelerometers made in accordance with the international standard ISO 16063 have to take into consideration the environmental conditions of the reference measuring chain, which is most frequently composed of a piezoelectric standard accelerometer and a charge amplifier. Manufacturers usually report only the temperature sensitivity of accelerometers for slowly varying ambient changes. Specifications range from typically -0.03%/oC for piezoelectric accelerometers that use quartz crystal elements to + 0.04%/oC for accelerometers that use ferroelectric elements. This paper focuses on the effect of temperature on the gain of charge amplifiers. Two different models of amplifier were placed in a temperature chamber and electrical calibrations using charge simulated input signals were carried out in the frequency range from 10 Hz to 10 kHz. The measurements were made at 2oC temperature steps between 18oC and 28oC. It was verified that, at each frequency, the gain of these amplifiers presented a linear behavior with temperature. A matrix of regression coefficients was determined from least squares fits to the measured data. Therefore, the effect of temperature on the amplifiers’ gain can be established for any temperature within the range of measurement. Relative deviations from the reference gain at 23oC are presented in graphical form. The presented methodology is a helpful tool for the choice of the best charge amplifier for an accelerometer calibration system and provides a way to evaluate and correct for the effect of an environmental parameter that can significantly influence the uncertainty of measurement in accelerometer calibrations.