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Development of a new porcelain suspension insulator with a semiconductive glaze and improved shape is described. The development was carried out jointly by Ontario Hydro and Canadian Porcelain Company. These new insulators provide considerably improved performance under wet and contaminated conditions and thus allow the reduction of insulator string lengths, facilitating conversion of existing 115 kV lines to 230 kV operation, and development of compact high-voltage transmission line designs.

Our industry produces a large number of precision wire-wound resistors, for instance, types MVSG, $5-5, $525, S5-42, etc. With a tolerance for deviations from their nominal values of 6 = i(0.03-0.1)%. The instruments most suitable with respect to precision and efficiency for testing these resistors consist of class 0.02 type R337 and class 0.005 type ShCh-30 digital ohmmeters in conjunction with resistance boxes types R32q and R326 (with corrections). However, these bridges are expensive, in short supply, and require highly-trained personnel for their testing and repai~. The measurement error of these ohmmeters is determined virtually by the precision class of the reference resistance box. By selecting appropriately the ratio-arm resistances of the dc bridges shown in Fig. 1 and employing the suggested method for choosing its supply voltage, it is possible to assemble from the components mass produced by our industry a comparison bridge for testing resistances in the range of 0.1-100 ka with an error not exceeding 0.015%. The bridge ratio-arm resistances R 1 and R z consist of resistors typeR331 with nominal values of either 1000 (for the measurement range of 0.1-10 k~) or 10000 ~ (range of 1-100 k~). The actual values of the resistors should not differ by more than ~: 0.001% with their temperature coefficients of resistance being close to each other. The resistors are selected by means of their certified records obtained in state testing. Such a selection from 25-30 available resistors with the above nominal values does not present any difficulties. The resistance R consists of the class 0.01 resistance box type R327. In measuring on this bridge the resistor Rx made with a tolerance of ~0.05% is balanced with adecade resistance box by setting it to the nominal value Rxn of the resistor. Owing to the difference between Rx and Rxn , the bridge will be slightly unbalanced. It is known [1] that the unbalanced voltage in this case (when the above-mentioned requirements with respect to the precision of R, R 1, and R 2 are met) can be determined with sufficient precision from the expression

This paper concerns the trigger performance of Marx circuits and shows the essential features of an improved circuit. It is studied how the introduction of parallel spark gaps PF and firing capacitors CZ in a multi-stage impulse generator can improve the trigger performance. Other advantages of the new circuit will also be discussed.

This paper presents the problem of overvoltage due to three-phase simultaneous interruption using vacuum switches. This three-phase simultaneous interruption is a new phenomenon which has not been known before. This paper presents the realities of over-voltage due to three-phase simultaneous interruption and the cause of three-phase simultaneous interruption. Surge suppression by the CR Surge Suppressor and Nonlinear Resistor which has been recently developed are also presented.

The usual method of calibrating carbon resistor thermometers against the vapour pressure of He 3 and He 4 is often inconvenient due to the nature of the experimental apparatus. Culbert and Sungaila have proposed a heat capacity technique in which the resistance-temperature relation is deduced by comparing the calculated internal energy-temperature function of a known sample to the measured internal-resistance function for the same sample. An improvement on their method utilizing holmium metal as a thermometric device is presented. The advantages, disadvantages, and reliability of this technique are discussed and a new carbon resistor thermometry equation of the form R = A + B/T + C/T 2 is proposed.

The interfacing of a spectrophotometer with a digital computer is discussed. The spectrophotometer collects and measures spectral and environmental data from agricultural crops and products to estimate yield and disease. The wavelength position of the spectrophotometer is coupled to the interface through an electromechanical encoder. The output signal and the signal from the interface are applied to the direct memory access interface (DR11-B) of the PDP-11. The processing of the spectral data is accomplished by the software interface.

The active circuitry for a digital autoranging multimeter has been fabricated on a single hybrie substrate measuring 2.8 X 3.8 cm. The hybrid is realized using tantalum nitride thin film technology. A high temperature passivation process stabilizes the tantalum nitride film. During this process, the absolute value of resistance changes substantially. This change makes the technology unusable in some precision applications. In order to overcome this problem and take advantage of the film's inherently excellent stability, laser trimming is utilized to adjust the absolute value. The result is a stable precision resistor. When the end result of the laser trimming process is a resistor of predetermined value, the operation can be performed by "passive trimming." In many cases, it is desirable to trim the resistor to an unknown value in order to obtain a given circuit response. When this is done to an operating circuit, the procedure is known as "active trimming." In general, a relationship can be determined between a known stimulus and its desired circuit response. The trim procedure can be designed to cause this desired relat onship. Specific algorithms and techniques have been developed to test the sensitivity of a circuit parameter to a given change in trim resistance. The computer controlled system uses this information to determine the succeeding trim magnitude. The use of a computer controller allows the system to handle complicated nonlinear stimulus-response data. Once a hybrid is trimmed, it is effectively a finished product. Since it has been calibrated during the trimming process, there is no need for manual adjustment. One difficulty associated with active laser trimming is duplicating the external circuit while at the same instant connecting the hybrid substrate to noisy probe rings, loading it with capacitances, and subjecting it to-the hostile environment of electromechanical controls. This paper will deal primarily with algorithms developed for active trim and the problems of electrically interfacing the system with the hybrid under test. Most of this experience was achieved during the development of the Hewlett-Packard Model 970A Probe Multimeter.

A systematic RC-active network synthesis procedure for the realization of second-order transfer functions is proposed. The realization employs a single generalized impedance converter which can be implemented by using only two operational amplifiers. The sensitivity to passive element variations are found to be low. The sensitivity to variations in the amplifier d.c. gain is minimized and found comparable to that in other low sensitivity structures. A design procedure is developed in which tuning can be achieved by trimming only resistors. With the exception of one case, second-order sections can be cascaded without additional isolating amplifiers. The stability properties as well as the influence of the finite bandwidth of the amplifiers are examined. The design procedure is used to obtain a sixth-order Chebychev low-pass filter, and a sixth-order elliptic band-pass filter. Experimental results show that these realizations are insensitive to temperature and power supply variations.

We present a voltage clamp (potentiostat) for biological membranes which works on a new principle. Its feedback loop contains a current clamp which drives a train of brief current pulses through the membrane (typically 8 μsec duration and 8 μsec intervals). In each interval between two current pulses, the difference between membrane voltage and command voltage is sampled and determines the amplitude of the next current pulse. Since the membrane capacitance acts as an analog store between current pulses, the membrane voltage oscillates near the desired value in a triangular waveform. It is independent of resistive voltage drops at electrodes or fluid layers developing in series to the membrane (or the electrode) to be clamped. The clamp does not tend to oscillate, in contrast to clamps with continuous feedback after compensation for series resistors. A precise measurement of membrane capacitance is possible.

Several aspects of carbon thermometry below 1 K are discussed. Some calibrations, performed on home-made carbon resistors, are presented. The lowest reliable calibration temperature was 25 mK. The reproducibility after thermal cycling of these resistors appeared to be good. Comments are given on our measurements, and also on those of others. It is very probable that the thermal resistance between the spin system and the lattice of the cooling salt is in many cases the main obstacle to the attainment of a low resistor temperature.

Some conventional methods of stabilizing transistor currents using temperature sensitive elements have been studied with a view to stabilize the voltage gain of the transistor amplifier. It is found that when the transistor currents of an amplifier are perfectly constant the a.c. gain of the circuit is not properly stabilized. A remarkable improvement in the stabilization of the transistor gain against temperature variations is possible through the use of a temperature sensitive element placed between the collector lead of the transistor and the load resistor RL. Relations have been derived to determine the value of the resistance of this element at various temperatures. When this element is heated along with the transistor, the gain temperature response of the amplifier is found to extend to temperatures upto 300°C.

The I C -V CE locus predicted by a one-dimensional model of thermal instability is compared with the I C -V CE locus predicted by a numerical model which accounts for nonuniform heat generation over the transistor area and also two-dimensional heat flow within the heat sink. Both models include the effects of distributed emitter and base ballast resistance, as well as the magnitude and temperature dependence of current gain. An important result obtained from this comparison is that the I-V loci predicted by the two models are very nearly the same, even though the temperature and power density profiles over the transistor die are distinctly different. It is the I-V locus which is of most practical interest, since it is one portion of the boundary of the forward safe operating area (SOA). The similarity of the I-V loci should allow one to use the simple one-dimensional model to predict a particular SOA, even though the assumptions under which the model was originally derived are not valid at the onset of thermal instability. Confirmation of this approach has been obtained by demonstrating good agreement between the measured safe operating area and that predicted by the one-dimensional model for both single- and double-diffused transistors. The predicted improvement due to the addition of discrete emitter resistors has also been verified by SOA measurements on actual devices. The device parameters which are important in determining SOA are the effective emitter and base resistances, the magnitude and temperature dependence of current gain, and the effective thermal resistance between the active region of the transistor and its heat sink. The quantitative dependence of SOA due to each of these parameters is described.

Several electronic circuits are described which increase the input resistance of inductive voltage dividers up to 109 ? at frequencies below 10 Hz. One of the circuits has been used to build an isolating inductive voltage divider consisting of 8 decades and having an input resistance of 109 ?. The in-phase errors are less than 2 parts in 10+8. This inductive voltage divider is the main part of an ac potentiometer for the precise measurement of low value resistors with comparatively high lead resistances. Lead resistances of 50 ? generate errors of only 1 part in 107. Apart from the preceding application, the inductive voltage dividers with high input impedance may also serve as a component of a voltage comparator. Such a comparator, for example, permits the calibration of a resistive voltage divider which is used for maintaining the unit of voltage via the Josephson effect and which, for such a purpose, is kept at a temperature of 2 K. An uncertainty of 5 parts in 10+10 is achieved for the measurement of a 1:1 ratio, even if the ratios differ by a few parts in 103 from 1:1.

To measure seawater parametersin situ a dc or an ac bridge is applied in general. The first type of bridge cannot be used directly in greater depths. Therefore the author has proposed for more than twenty years to apply an ac bridge for such purposes and in such a way that the parameters to be measured are transformed through the bridge either into a frequency of an oscillator, which depends on the parameter values or in a time interval which can be counted out. In both cases there are no difficulties to transport the parameter values via a cable from any depth. In ac bridges inductive or capacitive resistors are needed and the accuracy of the measurement is limited by the drift phenomenon of such resistances. An ac bridge with real resistances, being superior to those resistors, is proposed. It uses two ac voltages with constant frequency. In this case it is necessary to get an alternating voltageU for the one path of the bridge and an alternating voltagej· U with a phase angle of 90° in the other path. These bridges and some possible realizations of circuits are described in this paper. It could be shown that it is possible to reach an accuracy in measuring, for instance a temperature dependent resistor, of at least 20000:1 in one range. So a temperature value can be measured over a range of 40°C with an accuracy of at least 0,002°C, with a time interval of about 1 msec.

An experimental cryogenic measuring system, employing the dc and ac Josephson effects, which has been used to monitor the National Physical Laboratory maintained voltage standard is described in detail. Results obtained with this system over a period of 1 years are presented and compared with those from a system using room temperature potentiometry, which has already been described. Emphasis is laid on experience gained with cryogenic components of the system. The final section outlines a design for a portable Josephson apparatus based on experience with the present system, which would be capable of calibrating standard cells with maximum possible precision.

The application of superconducting direct-current comparators to the measurement of resistance ratios is described. One comparator consists of a binary set of ratios between 1:1 and 160:1 providing for self-calibration by a buildup procedure. A second comparator exhibiting discrete ratios of 1:1, 10:1, and 100:1 is also described. Ratio uncertainty of less than 1 part in 109 is achieved by enclosing the ratio windings in overlapping toroidal superconducting shields. Superconducting quantum interference devices (SQUID's) serve as flux sensors for the comparators. One of these current comparators is used to calibrate a 100-?:1-? resistive divider, which at a current of 10 mA exhibits a self-heating error of 0.0023 ppm.

A theory of diode structure based on the formalism of the potential Ψ is presented. Expressions describing static and dynamic dependences of (p–n)-(l–h) diodes as well as resistors with two l–h junctions have been derived. The recombination of carriers within the junction depletion layer and on the interface of the junction is neglected. The formulae thus obtained proved to be in agreement with those derived by other authors for particular cases. [Russian Text Ignored]

Temperature dependences of Speer carbon resistors between 30 mK and 4.2 K have been measured. The applied electric power at which the resistance decreases by 1% was measured accurately over the same temperature range. From these data, discussions of the thermal resistance of the resistors are made in detail. Some techniques to measure carbon resistance below 1 K, including the method to remove heat leaks, are described.

Thick film resistors have been prepared by adding glass frits to the conductive materials of the resistors. By this method, it is found that the resistance of the glass phases in the thick film resistors decreases, with a resulting decrease of voltage drift after applying high voltage pulses to the resistors. In addition, the electrical properties and stability of these resistors are improved over resistors made from some present commercially available pastes.

A new type of ADC is being developed to satisfy the requirements of the HEAO high spectral resolution gamma ray spectrometer. This 13 bit design utilizes a double successive approximation technique that overcomes the usual differential linearity problem. Stability of a few ppm/°C, differential linearity of 2% and integral linearity of 0.05% have been demonstrated.

Successful application of LVI methods to detect winding deformation after transformer short-circuit tests has made it feasible to use this technique as a maintenance tool to assess any deleterious effects of close-in faults on installed transformers. This report reviews Input and Voltage Differential methods, technique improvements and their application to field use. Short-circuit test comparisons are made with the Amplifier Differential method.

By expressing the output/input voltage ratio as a linear fractional transformation in the normalized resistances, six one-thermistor temperature-measuring circuits are analyzed and their common design parameters are emphasized. Conditions are derived for circuit operating point selection to maximize the transducer linear operating range.

We present a discussion on the definitions and characterizations of the four basic types of time-invariant electrical network elements, namely: resistors, inductors, capacitors and memristors, including the nonlinear multiport cases.

A computer-controlled dc bridge that uses several techniques to obtain a resistance measurement to 0.01 percent in under 2 ms is described. These include the use of FET range switching, the fast current output of a digital-to-analog converter, a voltage-clamped detector, an unusual current ratio circuit, a fast range-test method, and a PROM memory to reduce computer time. These techniques are discussed generally and some speed versus accuracy data are given for a specific bridge.

Parameters of the low voltage arm for damped capacitive dividers operating in the multi-megavolt region are analyzed. The influence of the residual inductance of the capacitive and resistive elements of this arm on the overall divider performance is examined experimentally through application of a new measuring technique. The desirable low inductance of these elements is in contradiction to the required dielectric strength and thermal capacity. A new optimized design of the low voltage arm is presented which can be manufactured in a normal high voltage laboratory workshop.

A longitudinal heat‐flow technique for precise measurement of thermal conductivity, electrical resistivity, and Seebeck coefficient over the temperature range from 80 to 400 K is described. The basis of the technique is the use of a calibrated platinum resistance thermometer to provide in situ calibrations of specimen thermocouples. The total determinate errors at 273 K are ± 0.23% for electrical resistivity, ± 0.49% for thermal conductivity, and ± 0.07 μV/K for the Seebeck coefficient when Pt wire is used as the reference. Experimental results on two high‐purity molybdenum specimens with cross‐sectional areas differing by a factor of four are presented to demonstrate the system precision and low level of indeterminate erros.

A computer program for the analysis and design of distributed lumped circuits, including microwave integrated circuits, is discussed. It is capable of frequency-domain analysis, optimization of transducer power gain, reflection coefficient, and/or noise figure. Also, the program can compute the return difference with respect to any admittance parameter so that the stability of the circuit can be determined by the Nyquist criterion. The program handles complex impedances, resistors, capacitors, inductors, transmission lines, independent current sources and grounded voltage sources, voltage-controlled current sources, and multiport elements, such as transistors and circulators, described by their scattering or admittance parameters. It contains a free-format input. The implementation is based on the indefinite admittance matrix, sparse matrices, adjoint networks, the Fletcher-Powell or Fletcher minimization algorithm, and Bode's feedback theory.

A novel method. for exactly realizing a rational transfer function using commensurate uniform RC lines (\overline{URC}) is presented. As an intermediate step in efficiently implementing the method, a new lowsensitivity grounded capacitor lumped RC active structure using operational amplifiers is developed. This structure leads directly to a low sensitivity distributed realization of a rational transfer function merely by replacing the lumped resistors and capacitors by short-circuited \overline{URC} 's and passive gyrators terminated by open-circuited \overline{URC} 's, respectively. It is also shown that if the RC product deviates from its nominal value, there is negligible effect on the response of the designed filter provided the RC product is properly chosen.

The design and operation of a cryogenic voltage comparator system for precision 2e/h measurements is described. Major improvements embodied in the new 2e/h system include the use of 1) a single microstripline-coupled Josephson tunnel junction to obtain usable step voltages up to 10 mV at 10.0 GHz, 2) a cryogenic voltage divider comprised of two resistors whose ratio is calibrated with a low-temperature dc current comparator, 3) a superconducting quantum interference device (SQUID) null detector, and 4) superconducting switching. The accuracy of the present 196:1 divider system is estimated to be about 2 parts in 108 on the basis of preliminary tests and is limited by resistor self-heating during calibration.

Summary The bandpass limitations of the potentiostat and current measurer may affect the shape and characteristics of the LSV polarization curves. This problem is studied in the case of a nernstian faradaic reaction controlled by linear and semi-infinite diffusion. Three independent parameters are in general required to characterize the effects of ohmic drop through the uncompensated resistance, double layer charging and bandpass limitations. Under critical conditions the number of parameters is reduced to two. The solution is given in the form of an integral equation which was numerically computed for various sets of parameter values mainly in the case of critical conditions. The main effects of bandpass limitations on the faradaic peak are a shift in the same direction as that due to ohmic drop and an enhancement of the peak height opposite to the effect of ohmic drop. These effects increase rapidly with the sweep rate. Working curves are given that allow the maximum sweep rate corresponding to a specified permissible error to be computed. With potentiostat and current measurer amplifiers having gain-bandwidth product pulsations of the order of 107 rad s−1, the effect of bandpass limitations in current practice of LSV falls into the range of experimental errors up to about 1000 V s−1. Such amplifiers having moreover high input impedance specifications and 6 db/octave operating gain-frequency characteristics are required anyway in order to ensure the transfer function to be second order with a good accuracy. The theoretical analysis was experimentally verified with respect to peak portion and peak height by introducing purposely an additional resistor in the potentiostat loop. Second order conditions appear to be the most convenient to reach the maximum analogical compensation keeping the possibility of measuring accurately the residual uncompensated resistance and of correcting the residual ohmic drop mathematically. The best operating conditions are shown to involve a slightly overoscillatory double layer response.

The recently completed upgrading program carried out on the University of Rochester MP Tandem Van de Graaff accelerator is described. The principal features involve new, small diameter, spiral tilt accelerator tubes, separate tube and column resistor chains, a new terminal configuration, terminal cryogenic pumping and various accelerator tube conditioning diagnostics. An analysis of voltage problems in MP tandems is presented, and the rationale for the relatively straightforward design changes that have been made is discussed.

The paper presents design tables for high-pass RC active filters having capacitors of equal value. The functions realized are of the third-order Butterworth and Chebyshev variety. Account is taken of the resistor spread, total resistor stun and of the summed network sensitivity.

It is proved that for the realization of a gyrator by nullors and resistors, at least two nullors and at least two resistors are needed. A generalization is the result that any n-port network possessing both an impedance and an admittance matrix and consisting of nullors and resistors must contain at least n resistors. It is conjectured that a realization of a gyrator with only two nullors requires four resistors and a realization of a gyrator with only two resistors requires three nullors.

The low-frequency noise spectra of partially annealed boron-implanted silicon resistors with various geometries are measured. The implantation energies are 50, 80 and 110 keV and the doses are 2·5 × 1012 cm−2, 1·0 × 1013 cm−2 and 1·0 × 1014 cm−2. The spectra exhibit thermal noise and ƒ −n (excess) noise exclusively. Investigations indicate that the contracts from the implanted layer to the electrode generally contribute small amounts to the total excess noise observed. The excess noise exhibits a strong dependence on the sheet resistance of the layers, while the dependence on substrate bias, implantation energy, and on temperature is relatively weak. A discussion of the results is given in terms of a volume effect. Noise measurements on implanted layers, produced under carefully controlled conditions, show promise as a tool to investigate excess noise.

Design, construction, and performance of a solid state marginal oscillator for detection of ions in ion cyclotron resonance experiments are described. Special design features include noise matching a high Q tank to an FET preamplifier which sacrifices voltage level for improved S/N ratio, amplitude limiting to remove noise from the feedback signal, and impedance matching the feedback resistor to the tank to minimize phase shift, parasitic capacitive coupling, and tank loading. A simple electrical circuit which simulates power absorption by ions for performance testing and comparison among marginal oscillators for icr applications is also described.

The design and performance of an audio-frequency four-terminal resistance bridge is described which compares resistors from 1 to 0.001 ? over a frequency range of 50 Hz-10 kHz. Current scaling establishes equal voltage across the resistors, permitting the standard to have the larger value and most optimum design while dissipating less power than the unknown. An amplifier-aided two-stage current transformer forms the ratio arms. Ratios of 1, 2, 4, 5, 10, and 20 are available, and a maximum applied current of 200 A is accommodated. Bridge ratio errors are less than 2 × 10-6 in both magnitude and phase at frequencies up to 1 kHz, increasing to 2 × 10-5 at 10 kHz. Simple transformer scaling techniques are described for producing accurate and stable resistance standards at the 0.001-? level.

The analysis for a distributed RC transmission line based on a circular geometry in which a plane circular resistive sheet is separated from a circular conductor by a dielectric is developed. Connections to this sheet are made using an outer circumferential electrode and an inner central circular electrode. Two types of notch filter are then analyzed, one incorporating a single discrete resistor and having a fixed notch frequency, and a second with a discrete resistor and a discrete capacitor in series combination that has a variable notch frequency. In common with notch filters based on linearly and exponentially tapered transmission lines, the filters described demonstrate improved selectivity compared with zero-tapered lines. The effect of loading that is likely to be encountered in experimental conditions is discussed.

A system is described for producing rectangular pulses up to 300 kV in amplitude with rise times of about 1 nsec and pulse widths adjustable between 5 and 20 nsec. A coaxial line is pulse charged from a Martin‐type autotransformer and then discharged by a fast‐rise high pressure switch into a matched CuSO4 load resistor. A low inductance, capacitive voltage divider allows monitoring of the pulse. The pulse reproducibility is excellent and the low jitter (250 nsec) in the discharge switch allows synchronization with other events. The system has been in use for two years with satisfactory results.

Results on the selective etching of a two layer system (resistive layer and conductive layer) on glass substrates to achieve resistors/resistor-networks have been described. This method is compared with the earlier used methods. The method reported in the paper results in good resolution of thin film patterns, smaller area flexibility, higher yield and lower cost.

An analog of resistors and regulated-current sources has facilitated the thermal design of end caps for nuclear reactor fuel elements. The analog permits cylindrical-symmetric representation of the end caps, adjacent fuel, and sheath. With the analog, temperature distributions in various complex geometry end-cap designs can be readily determined. Non-uniform radial and axial heat source distributions, external uniform or non-uniform heat transfer coefficient distributions, and arbitrary internal contact conductance distributions between components can be treated. A feature of the analog design is the regulation of currents to the nodal points within the simulated fuel region, insuring independence of the current loadings at other nodal points. This facilitates rapid setting of the required heat source distribution. The analog has been used in the design of end caps of fuel elements for different fuel designs. Screening of proposed designs has been accomplished, and design configurations optimized. The principles of the design can be applied to analogs used for many other purposes.

The operation of ion implanted silicon position sensitive detectors at low temperatures will be described. The improved noise performance of the detector at these temperatures in both the energy and position modes will be analyzed and its implications on low energy applications will be discussed. A large part of the investigation was devoted to the study of boron implanted resistors and their noise properties both at room temperature and cryogenic temperatures.

A zero‐frequency bridge has been developed for measuring the inductance and the current‐vs‐quantum‐phase relation of superconductors. The current null detector is a SQUID magnetometer coupled to the bridge by a superconducting transformer. The bridge is balanced by adjusting precision resistors at room temperature. The theory of the bridge and analysis of the null‐detector circuit for optimizing the sensitivity are given. For current‐dependent inductors, a definition of inductance based on the quantum‐phase difference is shown to be useful. Construction and operation of the bridge are described and measurements of inductance vs temperature for Al thin‐film meander lines are presented. Zero‐frequency measurements avoid the stray coupling to capacitances and normal metal inductances found in high‐frequency measurements and the method could give high‐precision absolute measurements. The sensitivity of the present instrument is such that an inductor of 4×10−7 H was measured to a relative precision of one part in 104 with a measuring current of 5×10−6 A. Considerable improvement is possible, especially for circuit elements of very small inductance such as Josephson junctions and weak‐link superconductors.

The cordwood module has been a part of the electronic Packaging concept for approximately ten years [1]. During that time period all variety of parts have been packaged in this configuration with varying degrees of success and reliability. With the coming of the space age and vacuum environments becoming commonplace, the removal of 'heat has become progressively more difficult with higher packaging densities ,and more' sophisticated piece parts. This paper describes methods utilized in the removal of heat from cordwood modules, arid takes some of the difficulty out of predicting thermal gradients.of piece parts within these modules. Fundamentally, the method is predicated on the use of the equivalent of Ohm's law. and the ability to realistically utilize proper piece part' thermal resistances. Design data and guidelines are presented that allows 'one to achieve designs for minimum weight, maximum thermal efficiency, and high reli- abil'ity.

It is shown that if there equivalently exist the virtual resistive elements in parallel with the inductive elements of the over-normal tree of a given linear active network or in series with the capacitive elements of the corresponding co-tree, an increase in the number of state variables arises. It is also shown that when a virtual resistor equivalently appears in parallel with the distinct resistor in a tree or in series with the distinct resistor in the co-tree, a decrease in the number of state variables may arise. This is, however, a rare case in the usual types of network. Two algebraic methods for obtaining the state equation of linear active networks are presented. One is useful for the networks in which the decrease in the number of state variables does not arise. From the other, the output equation for the required variables is obtained at the same time as the state equation. Further, the initial values are simply determined without iteration in many cases.

The area of static MOS memory cells is reduced by avoiding crossovers in the flip-flop, and by selecting the cell by a diode. Such cells have been realized in epitaxial silicon films on insulators (ESFI) with complementary transistors, diodes, and high-rated load resistors; the cell areas can be as small as 1500 /spl mu/m/SUP 2/ (2.4 mil/SUP 2/), and are the smallest areas of static MOS memory cells known so far. The static and dynamic behavior of these cells are discussed, as well as their behavior in a large-scale integrated (LSI) circuit; for this purpose an exploratory memory with 4096 bits and with simple decoding and sensing circuitry has been realized on an area of 3.5/spl times/4.2 mm (140/spl times/170 mils). Taking into account the measured data, an ESFI MOS memory circuit shows a better performance in speed and power dissipation than dynamic MOS memories, but its principal advantage is the static operation mode.

A simple, linear, wide range V-F converter which can be quickly constructed with two digital integrated circuits, two transistors, two capacitors and a resistor is described. Its applications are illustrated. In order to convey the simplicity of this design, and (to the author's mind) the complexity of more widely used types the principles of the latter are described first.

A multilevel thin-film process has been developed for fabricating experimental circuits containing Josephson tunneling gates, insulated crossings, superconducting contacts, and terminating resistors. The process utilizes a Nb film for the ground plane and Pb alloy films for overlying superconducting layers. Insulation is achieved through the use of vacuum-deposited SiO films and anodization of the Nb ground plane. An oxide formed by rf sputter-etching in an oxygen plasma is used for forming the tunneling barriers. Photoprocessing techniques are used for patterning. Through use of the process it has been possible to fabricate experimental memory and logic circuits which survive thermal cycling to 4.2 K and intervening storage at room temperature without significant changes in electrical characteristics.

Theoretical expressions for the spectra of the noise in a galvanometer, a seismometer, and a seismometer-galvanometer seismograph are derived from electrical analog circuits and from the Johnson noise of the resistive elements in these circuits. The contributions of the internal damping of the seismometer and of the galvanometer, and of the series resistor to the total potential energy of the thermal noise in a high-sensitivity long-period seismograph are explicit in the expressions. The theoretical thermal spectra agree with observations made at Las Cruces, New Mexico (LC-NM), and at Queen Creek, Arizona (QC-AZ). At LC-NM, the outputs from two matched vertical seismographs were subtracted to obtain estimates of the individual seismograph noise at periods from 4 to 800 sec. Additional experiments demonstrated that the seismograph noise between 10 and 1,000 sec could be estimated equally well by replacing the seismometer: (1) with a resistor, (2) with a coil and magnet oriented vertically or north-south, or by (3) rigidly blocking the seismometer mass. The observed spectra from LC-NM indicate an excess noise in the electronics of the galvanometer phototube amplifier (GPTA) having a one-over-f character at periods longer than 300 sec. At QC-AZ, seismograph noise was recorded with a resistor substituted for the seismometer. The observed noise spectra agree identically with the theoretical noise spectra at periods from 25 to 60 sec and with theoretical noise spectra plus a 1/f noise in the GPTA electronics at periods out to 2,560 sec. The QC-AZ observed and theoretical noise spectra are plotted from 3 to 2,560 sec as the mean-square voltage at the seismograph output and as the root-mean-square displacement of the ground that would produce the same signal as the noise. Typical minimum vertical amplitude spectra of the microseismic background are above the instrument noise spectra in the period range from 3 to 2,560 sec. The agreement between the theoretical thermal noise spectra and the two sets of observational spectra confirms the validity both of the theoretical expressions and of the experimental procedures.

A potentiometric technique for accurately determining a fixed voltage ratio has been developed which employs a voltbox subdivided for optimum self‐calibration. The calibration procedure minimizes the effects of resistor self‐heating and interconnection resistances which are commonly limiting factors. The basic theory of the technique and the design and construction of an instrument to compare a Josephson device (10 mV) and a standard cell (1 V) are described. This cascaded‐interchange comparator (CIC) was evaluated in conjunction with another instrument, based on the double series‐parallel exchange technique, in a series of 2 e/h measurements and direct instrument comparisons. The over‐all uncertainty for the CIC was about 3 parts in 108 (1σ) and the direct comparisons between the two instruments agreed to within their combined uncertainty of 4 parts in 108. The cascaded‐interchange technique should also be useful for the accurate measurement of high voltages.

It is well known that certain impedance matrices, which can be realized by multi-ports containing only inductors, capacitors and resistors, can only be realized in this way when more reactive elements are used than the McMillan degree would suggest. The redundancy which this implies is investigated and it is shown to be of three types, which can exist alone or in combination. In particular, the multiport may have least order in spite of the redundancy.