Abb Patent Gmbh

Brown, Boveri & Cie Ag

Herbert Ziegler

Gunter Roppelt

Robert Kindermann

Karl Hochreuther

Carl W Clever

Klaus Styhler

Horst Hopfner

Fuerth Schick

Guenter Roppelt

A measuring circuit for measuring a capacitance according to the discharge method includes a measuring circuit input. A constant voltage source charges a capacitor to be measured at the measuring circuit input. The capacitor discharges through a discharge resistor with a known resistance being connected to the capacitor. At least one switch is connected between the capacitor and the constant voltage source. A flow control is connected to the at least one switch for controlling the at least one switch. A comparator is connected to the capacitor. A counter is connected to the comparator for counting clock pulses during a discharge. A PTC element is connected to the measuring circuit input in series with the capacitor. A monitoring device is connected to the capacitor.

Circuit for measuring a capacitance during constant charging and

In multimeters having a plurality of input connections there is a danger of the measuring conductors being incorrectly connected in such a manner that the setting of the measurement range switch does not correspond to the input connections to which contact is made. In order to avoid damage which may be caused by making an incorrect contact to the input connections, an electrically and/or mechanically acting disabling device is coupled to the measurement range switch for permitting a disabling of particular input connections. The disabling is carried out in such a manner that contact can always only be made to that input connection for receiving a test signal through the measuring conductors, to which a measurable variable is assigned that corresponds to the measurable variable set with the measurement range switch.

Multimeter with at least three input connections and means for

A method for measuring the difference between two voltages with a time-controlled measuring cycle includes feeding two voltages with opposite polarity to one integrator, initially integrating up one of the voltages and subsequently integrating down the other of the voltages with the integrator in an integration cycle, and delivering a voltage corresponding to the mean valve of the difference between the voltage at an output at the conclusion of the integration cycle.

Measuring method for determining the difference between an A-C voltage

A method and apparatus for fixing an instantaneous measured value performs the steps of creating measured values as a mean value of a set number of individual measurements, recording sequential measured values after initialization in a cycle determined by a flow control, checking with a control device if a new measured value exceeds a base value and if the difference between the two latest measured values lies within a given limit range, before fixing the respective new measured value, and checking with the control device if the difference between the individual values resulting from the latest two individual measurements lies within the given limit range and if a fixing of the last measured value and/or individual value takes place when the differences between the mean values and the differences between the individual values lie in the respective given limit range.

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Nuremberg, Germany

Herbert Ziegler