DEVICE FOR CONVERTING THE RESISTANCE CHANGES INTO VOLTAGE

FIELD: measuring equipment.SUBSTANCE: invention relates to electrical measurement techniques, in particular to electrotensometry, and can be used in the aircraft industry, engineering, construction for the study of the structures strength with the help of a single strain gage in the frequency range from 0 to 5,000 Hz and more at an increased level of interfering factors - electromagnetic interference and thermoEMF. Device for converting changes of resistance to voltage comprises a strain gage, a resistor, a switch, a differential amplifier, a bipolar rectangular current source and a subtraction circuit, the current source outputs through the normally closed switch contacts are connected in parallel to the strain gage and through normally open contacts - parallel to the resistor, the inputs of the differential amplifier are connected through normally closed contacts in parallel to the strain gage and through normally open contacts - parallel to the resistor. Output of the differential amplifier is connected to the input of the subtraction circuit. In addition, sequentially coupled synchronous inverting amplifier, a low-pass filter and an output amplifier, the output of the subtracting circuit being connected to the input of a synchronous inverting amplifier, and the output of the output amplifier generates the output of the device. Input of the low-pass filter receives an additive mixture of a unipolar sequence of pulses modulated by a useful signal according to AIM-1, and a bipolar sequence of pulses modulated by an interference signal. Low-pass filter rates allocate a spectrum of the useful signal and effectively compensates for the noise pulses in a wide frequency range, while the amplitude of the useful signal at the output of the filter does not depend on the frequency of the signal. Output amplifier enhances the signal from the low pass rates filter to the desired level, the output of the output amplifier is the output of the device. Result of the conversion is the amplified signal of the strain gage, while the frequency range of the conversion is extended and the non-informative signal components that determine the basic measurement errors are compensated.EFFECT: technical result consists in increasing the measurement accuracy in the extended frequency range of the measured processes up to 5,000 Hz and more against the background of disturbing factors - electromagnetic interference and termoemf at a clock rate not more than 16 kHz.1 cl, 3 dwg Изобрет