Apparatus for measuring the value of a variable co

专利名称：Apparatus for measuring the value of a

variable condition

发明人：John Rudolph Matthew Chlupsa申请号：US05/613339申请日：19750915公开号：US04025736A公开日：19770524

摘要：The current flowing through a variable resistor of a transducer, responsive to avariable condition, is measured without interference with the normal operation ofelectrical circuitry to which the resistor is connected. Current-diverting means, connectedin series with the transducer resistor, diverts the transducer current to measuringcircuitry which includes a current to voltage converter operating in a manner to returnthe diverted current to the electrical circuitry. Means responsive to the output of theconverter and to reference voltages derived from the electrical circuitry, provides outputvalues corresponding to the state of the variable condition at the time a measurement ismade.

In a specific embodiment of the invention, the apparatus monitors the internal gaspressure of a pressurized telephone cable without interfering with the normal use of asubscriber's equipment. The telephone company voltage source is used to produce aflow of current through a pressure to resistance transducer during the `on-hook`condition of the subscriber's lines across which the transducer resistor is connected.Current-diverting means, inserted into one line of the subscriber, diverts current from thetelephone company equipment to measuring circuitry which converts the current flowing

through the transducer resistor to pressure values.

申请人：RFL INDUSTRIES, INC.

代理人：Rudolph J. Jurick

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