Title:
METHOD FOR CONVERTING MEASURED SIGNAL, ITS CONVERTER, MEASURING INSTRUMENT AND PIRANI MEASUREMENT CIRCUIT
Document Type and Number:
Japanese Patent JP3213125
Kind Code:
B2
Abstract:
PURPOSE: To perform approximate conversion of measurement signal by, when a measurement signal is approximate converted into a related value with a specific equation, using the relation among a collector current, base and emitter voltages of two or more bipolar transistors.
CONSTITUTION: Letting measurement signal x be the output voltage of Pirani vacuum gauge, kN the asymptotic value when measurement gas pressure drops, kZ the asymptotic value against high pressure value and k1 the constant, a physical value y corresponding to the pressure of a vacuum gauge is expressed by y=k1 (x2-kN)/(kZ-x2). When its approximate expression is transformed by using logarithm, the following equation is obtained: lny=prop. [ln (x-kN)-ln (kZ-x)]+c (c is a constant, rrop means proportional relation ship). Then, a measurement signal x is sent to a non-inversion input of an operation amplifier OP1, and an asymptotic value kZ to an inversion input. In addition, an asymptotic value kN is sent to an inversion input of an operation amplifier OP2, and a measurement signal x to a non-inversion input. From a relation ship among collector current and base and emitter voltages of bipolar transistors T1 and T2, an output voltage Uort is equal to (y) of the previous equation.
Inventors:
Rudolf Stockel
Application Number:
JP17917093A
Publication Date:
October 02, 2001
Filing Date:
July 20, 1993
Export Citation:
Assignee:
Unaxis Balzers Akchen Gesell Shaft
International Classes:
G01D3/02; G01D3/036; G01L21/12; (IPC1-7): G01L21/12; G01D3/02
Domestic Patent References:
| JP59195773A | ||||
| JP4737587A | ||||
| JP62176142U |
Attorney, Agent or Firm:
Shoichi Ui (4 others)