A method for reducing the influence of mechanical disturbances in a magnetic field measuring system which uses a loop positioned in the field and oscillatable due to interaction between the field and a current in the loop, the loop being supplied by an alternating current having a frequency considerably higher than the mechanical resonant frequency of the loop, employs a signal which is a component of the mechanical resonant frequency of the loop; the signal being fed back to the loop to obtain ...

The combined current and voltage measuring apparatus has a cast resin body which supports the current measuring unit. The voltage measuring unit includes a capacitive voltage divider with an amplifier connected thereto. The cast resin body is also utilized as dielectric for the capacitor on the high-voltage side of the capacitive voltage divider. Embedded in the cast resin body is an auxiliary capacitor with a dielectric which, with respect to temperature dependence, corresponds to the dielectri...

A method and apparatus for detecting and measuring non-synchronous frequency oscillatory power in a power transmission system. Current measuring devices and voltage measuring devices are connected to supply signals corresponding to instantaneous currents and voltages in the system. The current and voltage signals are combined in a multiplier to produce a signal proportional to instantaneous power in the system. The power signal is processed through a filter circuit to remove the average value co...

A pilot insulator for detecting a degree of contamination thereof comprising a portion having a known exposed surface area whose degree of contamination is to be measured and means for supporting said portion and made integral therewith to form an assembled body whose configuration as a whole is substantially the same as that of insulators used in practice whereby said portion is removed from said assembled body to submit said portion thus removed for measurement of the degree of contamination t...

A fault detection system including first and second transducers adapted to receive alternating current, a common conductor coupled to the transducers, and a failure detector. The alternating current from the transducers is substantially oppositely phased so that, under normal operating conditions, the current level on common conductor is relatively low. When a failure in one of the transducers occurs, the current level on the common conductor increases at least to a predetermined level. The fail...

This invention relates to methods of measuring magnetic fields and a magnetometer for performing the method. According to the method an alternating magnetic field is applied to a thin magnetic film along its axis of difficult magnetization. The alternating magnetic field applied to the film has an amplitude which is less than the anisotropy field of the film, the direction of magnetization of the film then undergoing an oscillation without reversal. An electrical signal representing variations p...

The testing apparatus disclosed herein is adapted to test backplane wiring so as to determine if all desired connections exist and whether any undesired connections may be present. Such backplanes typically comprise a multiplicity of terminal points which may be interconnected in arbitrary manner to form a plurality of networks of connected points. The tester employs an addressable switching and memory unit for each terminal point. When addressed, each point is first connected to a first bus and...

A capacitance-voltage converter, in which an unknown capacitance of a measured capacitor is converted to an output dc voltage indicative of the unknown capacitance. The measured capacitor is charged by a reference dc voltage. All the charge of the measured capacitor is transferred to a reference capacitor, after discharging the reference capacitor, by connecting the terminals of the measured capacitor to the input and the output of an impedance converter, which has a high-impedance input and a l...

The survey recorder is disclosed as being assembled in a rectangular shaped casing having a hinged cover. Stop means are provided on the hinge cover to prevent its closure in the event that the recording mechanism is not correctly engaged. An arm member which carries the recording head is pivotally mounted in the tape cartridge receptacle such that it can be swung down into operating engagement with the magnetic tape portion extending between the supply reel and the takeup reel of the tape cartr...

A pulse technique and network are described for measuring the reverse leakage current of an operating IMPATT diode. Observation under substantially operating conditions is attained by pulsing the diode under test out of the avalanche condition very briefly and observing the reverse leakage current. High reverse leakage currents under these conditions indicate likelihood of "short out" failure.