Abstract: ISFET measuring probe with a housing in which an ISFET and a reference electrode are arranged in such a way that the gate electrode of the ISFET, which is coated with an ion-sensitive layer, and the reference electrode reach into a measurement space into which a measurement medium can be introduced, with the distinguishing feature that an auxiliary electrode is arranged additionally inside the housing and is held inside the measurement space.

Abstract: ISFET measuring probe with a housing in which an ISFET and a reference electrode are arranged in such a way that the gate electrode of the ISFET, which is coated with an ion-sensitive layer, and the reference electrode reach into a measurement space into which a measurement medium can be introduced, with the distinguishing feature that an auxiliary electrode is arranged additionally inside the housing and is held inside the measurement space.

Abstract: A heat conducting support having electrodes is located in a chiller block. The electrodes form a temperature sensor, a heater electrode and electrodes for the measuring of the conductivity. The electrodes are covered by an electrically insulating layer, which layer limits or defines, respectively, over a length L a bedewable surface. The chiller block is encased in a heat insulation and its temperature is measured by a second temperature sensor. The cross-sectional area of the heat transfer between chiller block and bedewable surface is substantially smaller than the bedewable surface itself. This makes it now possible that the temperature at the bedewable surface during the forming of the condensate is determined substantially by the temperature of the condensate at the bedewable surface such that increasing formation of condensate a plateau is determinable at the dew point temperature.

Abstract: A process of calibrating a temperature sensor includes bringing the sensor to thermal equilibrium at a selected temperature, measuring the resistance of the sensor, calculating which combination of trimming paths need be interrupted and then separately interrupting those paths apart from the measuring location. A sensor with selectably interruptable trimming paths is disclosed.

Abstract: At least two electrodes (1, 2) each provided with at least one lead (5) are applied in the form of conductor tracks to a substrate. The leads (5) can be made of a material having a lower standard potential than that of the electrodes (1, 2). A dielectric (6) covers the electrode ends and, up to the contact points (4), the leads (5). As required, the electrodes (1, 2) can be designed and used as a heating electrode and/or as a temperature sensor. Moreover, the electrodes can be arranged on one side or on both sides of the substrate board (7).

Abstract: A method of measuring the impedance of a sensor by applying a sine-shaped AC voltage and transforming the response signal proportional to said impedance into a DC voltage such that even for very little measured voltage highest linearity is present. The method comprises the steps of generating a square wave voltage together and in synchronism with said AC voltage, applying said AC voltage to said sensor impedance, filtering the resulting AC voltage and bringing it into a defined phase relation to the square wave and rectifying the AC voltage by means of a switch controlled by said square wave. The rectifier circuit is a low-pass circuit having a grounded resistor which by said switch intermittedly is short-circuited.