Abstract: A printed circuit board transformer has primary and secondary windings. The transformer includes a printed circuit board having a plurality of traces forming a plurality of first portions of the primary and secondary windings, an annular magnetic core adjacent to the printed circuit board, and a plurality of second portions of the primary and secondary windings. The second portions are formed from conductors enlacing the core.

Abstract: A RF test interconnection system for connecting a measurement device to a device under test includes, a probe card having a probe extending from a first side of the card for making electrical contact with the device under test and a coaxial connector extending from a second side of the card, a test head having a test head coaxial connector that will mate with the probe card coaxial connector when the probe card and the test head are urged together, and a de-mating device attached to either the probe card or the test head for urging the probe card and the test head apart by applying a separating force therebetween. The probe card and the test card coaxial connectors are electrically connected when the test head and the probe card are urged together by a connection force and electrically disconnected when the connection force is removed.

Abstract: Corona charges are used to bias a wafer to push down mobile charges and then pull them up during temperature cycles. Mobile charge is measured from the drops in the corona voltage due to the mobile charges. Corrections are made in the measurements for dipole potentials, leakage and silicon band-bending.

Abstract: A power supply is provided with independently adjustable voltage and current sources to provide a power supply having a desired voltage-current relationship to a device under test. This allows the control of the power supply output impedance as seen by the device under test and the emulation of a battery or other power supply having particular voltage-current relationships.

Abstract: A bi-directional current scaling preamplifier is inserted between a device under test and a source measure unit or a source measure unit and switching matrix combination. The bi-directional current scaling preamplifier is formed from an operational amplifier, a range-changing network, and a voltage to current converting circuit. Either the network or the converting circuit is provided with an inverter. The elements are arranged so that current from the source measure unit into the device under test is bi-directionally scaled.

Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.

Abstract: A low leakage solid state switch for range-changing uses a pair of low leakage diodes switched to a reference voltage to block leakage through the switch when it is in the "off" state.

Abstract: An integrated modular measurement system includes a universal module which is operable to receive measurement data from one or more measurement sensors, convert the measurement data into a value that represents a characteristic being measured and indicate the value to a user in a plurality of signal formats. An input module is coupled to the universal module and is operable to house one or more measurement sensors. The universal module and input module together operate to provide versatile measurement acquisition. A custom calibrated sensor module includes one or more sensors and a memory associated with and local to the one or more sensors. The memory contains calibration information which is uniquely associated with the sensors. In taking a measurement, the calibration information associated with the sensor taking the measurement is accessible for conversion instructions to thereby improve conversion accuracy.

Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.

Abstract: Corona charge is applied to an oxide layer on a semiconductor wafer. Then ultraviolet light is used to erase a grid pattern of the corona charge. Opposite polarity corona charge is then applied to the layer, resulting in a grid of field-induced PN junctions. The surface photovoltage of the junctions is measured over time to provide a measure of the mobile charge in the oxide layer.

Abstract: A semiconductor probe card is provided with low dielectric absorption feed-through contacts to isolate test lines from printed circuit board leakage effects.

Abstract: A dose distribution analyzer (20) and methods for providing a radiation dose map indicating energy of a spacially variable radiation pattern beamed onto a dose map radiation dosimeter (10). The radiation dosimeter (10) is exposed to a proposed spacially variable radiation pattern such as used in a phantom patient for patient radiation dose treatment verification. The dosimeter (10) is subsequently analyzed by the dose distribution analyzer (20). Such analyzer includes a phosphor stimulator (53), an image forming subsystem (38), and an image sensor (37). A dosimeter holder (32) holds the dosimeter near the phosphor stimulator (53). A system controller (22) is connected to receive image data from the image sensor (37) while the dosimeter (10) is stimulated. The controller (22) utilizes the image data to derive a radiation dose map which indicates the distribution of radiation in the spacially variable radiation pattern which strikes the dosimeter (10).

Abstract: A matrix of three pole, high speed, low current relays for connecting test equipment to a device under test is provided with improved interconnect buses. The relays are mounted in rows and columns with their three pairs of leads extending vertically. An input interconnect bar having three conductors extends horizontally along each row of relays, each conductor being connected to a respective one of each pair of leads. A bottom interconnect bar having three buses extends perpendicular to the top interconnect bars along each column of relays, each bus being connected to a respective one of the leads. The ends of the leads are aligned at a 45.degree. angle with respect to the interconnects. The interconnect bars are enclosed in shielding guard tubes and are removable to permit replacement of the relays.

Abstract: The secondary of a line powered transformer supplies power to a measurement unit. The measurement unit measures between a high test terminal and a low terminal on the secondary. The low terminal is connected to a low test terminal through a common mode current sensor to a device under test. The device under test is also connected to the high test terminal. The common mode current sensor senses current through the transformer capacitance that flows through the device under test to earth ground. A current source is connected in parallel with the low terminal and earth ground. In response to the current sensor, the source dynamically drives a current through the device under test that drives the common mode current to a minimum.

Abstract: A conductive screen is placed between a corona gun and the surface of a semiconductor wafer. The charge deposited on the wafer by the gun is controlled by a potential applied to the screen. A chuck orients the wafer in close proximity to the screen. A desired charge is applied to the wafer by first applying a surplus of one charge to the wafer and then depositing an opposite polarity charge until the potential of the wafer equals the potential of the screen.

Abstract: A reed relay is provided with two shields. The shields are fabricated from copper foil and insulated from each other by polyester tape or film. One shield is connected to one lead of a switching element and the other shield is connected to another lead of a switching element. The shields are wrapped around the switching element in an overlapping manner. The dual shield configuration reduces leakage and interference to improve performance, particularly in low current applications.

Abstract: Apparatus is provided for continuously compensating for the dielectric absorption effect in a measuring capacitor in a circuit which employs means for charging the capacitor to develop an output signal thereacross and wherein the absorption effect causes an error in the output signal following a charging interval. The dielectric absorption effect is represented by at least one impedance branch connected in parallel with the capacitor and this branch includes a resistor and a capacitor connected together in series and having a RC time constant. Compensating means is provided having a correction means associated with the impedance branch and wherein the correction means continuously receives the output signal and provides therefrom a compensating signal. The correction means has a time constant that corresponds with that of the associated impedance branch. The compensating signal is combined with the output signal to provide a compensated output signal.

Abstract: A dual entrance window ion chamber is provided for purposes of measuring x-ray exposure. The ion chamber includes a housing having a cavity formed therein and which defines an ion chamber. The housing has oppositely disposed first and second openings therein located on opposite sides of the chamber. First and second x-ray entrance windows respectively cover the first and second openings for permitting entrance of x-rays into the chamber. A collector is located in the chamber intermediate the first and second windows for collection of electrons for use in measuring x-ray exposure. The first and second windows are constructed differently from each other such that the first window is optimized so that the ion chamber provides a relatively flat energy response to x-rays over a first x-ray energy range. The second window is optimized so that the ion chamber provides a relatively flat energy response over a second x-ray energy range.

Abstract: A current in a circuit is measured without breaking the circuit. A relatively low resistance element in the circuit such as a component lead is chosen. A current is forced through the element and the voltage drop measured. Another current is forced through the element and the voltage drop measured. The values of these currents and voltages are used to determine the original current in the circuit.