Abstract: A measuring instrument has a measuring configuration and a measuring circuit. The measuring circuit determines the capacitance of a capacitor and the conductance of the measuring configuration, which is formed of a casing and a sensor element around which a mixture flows. The alcohol content of the mixture is determined therefrom. The measuring circuit has an oscillator and a control circuit connected upstream thereof. The measuring configuration, which is represented by the capacitor and the conductance, is a part of the oscillator, which oscillates within a measuring cycle at three different oscillator frequencies which are set by three different control voltages of the control circuit, and evaluated in a microcontroller. Component tolerances which influence the oscillator frequencies can thus be taken into account.

Abstract: According to the present invention, a pulse of short duration is generated from system voltage and is applied to a circuit branch being tested. The resulting current is measured and subjected to a comparative evaluation. The corresponding arrangement has a power semiconductor circuit for generating the testing pulse from the system voltage. Preferably, a so-called GTO (Gate Turn-Off thyristor) is used for this purpose.

Abstract: It is an object of the present invention to prevent variations in sensitivity of the sensor circuits of the respective channels by equalizing the power of oscillation frequency signals to be distributed/supplied from one oscillation circuit to the sensor circuits of the respective channels. Multi-channel sensor circuits are arranged with a common oscillation circuit. A high-impedance conversion circuit is connected to the output terminal of the oscillation circuit. A first impedance matching circuit for performing impedance matching of resonance circuits of the respective channels with reference to the oscillation circuit is arranged on the output side of the high-impedance conversion circuit. Second impedance matching circuits for performing impedance matching of the oscillation circuit with reference to the resonance circuits are connected at the input terminals of the resonance circuits of the respective channels.

Abstract: A multi-channel electromagnetically transparent voltage probe transmission link system for monitoring a plurality of voltage signals at a plurality of test points of a device under test that is subjected to a radiation field. Each channel includes two voltage probes, an electrical to optical signal transmitter, an optical signal transmission line and a receiver located out of the radiation field. The voltage probes contact and sense the voltage signals at the test point. The electrical to optical transmitters are removably mounted in a common base and are powered by either a common (or shared) power supply and/or by dedicated power supplies, such as rechargeable batteries. The receivers process the optical signals and provide display signals corresponding to the sensed voltage signal at the plurality of test points for evaluating the effect of the test radiation field.

Abstract: A method and apparatus for determining the quality of a colloidal suspension. According to the method of the present invention, an oscillating input electrical signal is applied simultaneously to a sample of the colloidal suspension to be tested and to a reference solution. The reference solution is substantially identical to the colloidal suspension except that the colloidal particles have been removed. The input signal causes charge particles and molecules within both substances to move, thereby, giving rise to electrical currents. Thus, a test current is extracted from the colloidal suspension and a reference current is extracted from the reference solution. Thereafter, a differential output current is derived by substracting the reference current from the test current. The peak-to-peak magnitude of the differential output current is measured, and the phase of the output current is compared to the phase of the input signal to determine the difference in phase between the two signals.

Abstract: A circuit and a method for measuring a quantity influencing the capacitance-voltage characteristic of a capacitive element, the measuring accuracy and the signal-to-noise-ratio being improved by determining such quantity on the basis of the area under the curve of the capacitance-voltage characteristic.

Abstract: In a method of diagnosing deterioration of a paint film, a probe is applied to the surface of a paint film. A voltage having a predetermined waveform is applied by a preamplifier across the probe and a base metal on which the paint film is formed. A current flowing through the paint film is measured by the preamplifier. An analog signal indicative of a measured current value is converted to a corresponding digital signal by an analog-to-digital converter. A personal computer operates to analyze the digital signal in accordance with a predetermined analyzing procedure so that the degree of deterioration of the paint film is determined. The resultant determination is displayed on the display.