COMMUTATION UNIT FOR CAPACITIVE PICKUP Russian patent published in 2006 - IPC G01D5/24 

FIELD: electric engineering.

SUBSTANCE: commutation unit for capacitive pickup has measuring capacitor K_M1 which has capacity to be determined by measured value p, reference capacitor K_Ref1 and buffer amplifier OV₁. Input of buffer amplifier is connected at least temporary to measurement capacitor K_M1 in such a manner that signal voltage is applied from output of buffer amplifier OV₁ which voltage is proportional to voltage of measurement capacitor K_M1. At the beginning of any measurement cycle, measurement capacitor K_M1 discharges till residual charge and reference capacitor K_Ref1 charges till specified reference charge. Then reference charge is transmitted from reference capacitor K_Ref1 to measurement capacitor K_M1. For the purpose, input and output of buffer amplifier OV₁ are temporary connected with together during operation through reference capacitor K_Ref1. Commutation unit forms signal voltage which depends on value being opposite to capacitance of measurement capacitor. Moreover, consumption current practically doesn't depend on current value of capacitance of measurement capacitor K_M1.

EFFECT: improved efficiency of operation.

17 cl, 4 dwg