Chauncey G. Suits

Studies in Non-Linear Circuits

The series circuit consisting of an inductance L, capacitance C, resistance R, and a source of alternating electromotive force, where the circuit elements are all linear, is regarded as a special case of a more general type of circuit in which L, C, and R may be functions of the current or other variables. The practical importance of these non-linear circuits is noted and some of their properties are reported. In the series circuit with a linear resistance, capacitance, and an iron core inductance it is shown that the abrupt rise in current at a certain critical voltage is characterized by resonance in the sense that L di/dt = - 1/c ∫ i d t. In this non-linear resonance however the above condition is satisfied in but a limited portion of the cycle. During this portion of the cycle the peak current may be calculated from Ohms law. The series circuit with linear resistance, capacitance, and an iron core reactor with superimposed steady magnetizing force, is shown to exhibit a pulsation oscillation which is explained on the basis of the positive impedance-current characteristic of such reactors. Parallel resonance for the non-linear case of an iron core reactor is reported, and it is shown that in conjunction with series resonance the unique characteristic is obtained wherein the r. m. s. current decreases with increasing applied voltage.

Stabilizing Arcs by Electrode Surfacing

The effect of electrode surfacing on arc stability is studied for arcs between copper and silver electrodes in air at atmospheric pressure. For the copper arc it is shown that the random fluctuations in arc voltage and light intensity may be reduced to a very small value by giving the anode surface a high polish. Observations of the spectrum and volt‐ampere characteristic are described. For the silver arc partial stability of arc voltage and light is obtained by electrode polishing.

A VOLTAGE SELECTIVE NONLINEAR BRIDGE

The important property of the simple series resonance circuit employing resistance, capacitance and an iron core reactor arranged to saturate is the abrupt increase in current at a certain critical voltage. This phenomenon is identified as a quasi‐resonant condition, and is compared to resonance in linear circuits. An experimental study is made of a nonlinear bridge circuit comprising two branches of the above type. This bridge is voltage selective in such a manner that the load is only energized thru a certain range (of the supply voltage), which may be small. The variation of bridge output voltage (effective) with bridge supply voltage may be critical. In one case it is observed that 1/100 percent change in supply voltage changes the output (load) voltage by 100 percent. The properties of the bridge circuit are applied to the problem of voltage selective relays which permit the control of many circuits by means of a two wire system. For a bridge comprising identical capacitance and inductance units, but...

Non-linear circuits for relay applications

Study and analysis of non-linear circuits reveal characteristics which mark them as capable of being adapted to a variety of special uses. A simple series circuit of this type is especially well adapted for relay applications, and obviates some of the undesirable features of mechanical relays.

New Applications of Non-Linear Circuits To Relay and Control Problems

The fundamental relations between voltage and current for an iron core reactor are reviewed. The theory of the performance of such reactors in series and parallel resonance circuits may be qualitatively obtained by graphical means. For reactors which have nearly linear properties the graphical method is capable of yielding quantitatively accurate results. A fundamental analogy exists for the properties of series and parallel resonance circuits employing the same inductance and capacitance elements. It is shown that; (a) for the series circuit the current is functionally related to the voltage in the same manner as, for the parallel circuit, the voltage is related to the current, if (b) for the inductance element the current is functionally related to the voltage in the same manner as, for the capacitance element, the voltage is related to the current. It is stated that in the series or parallel circuit, means are available for causing the current, as the dependent quantity, to vary as a function of voltage, as the independent quantity, or vice versa. Because of this generalization, the series circuit which is sensitive to voltage changes can also be caused to function as a constant-voltage source, insensitive to current changes. Similarly the parallel circuit, which is sensitive to current changes, can be used as a constant-current source, independent of voltage changes. The voltage sensitivity of the series circuit and the current sensitivity of the parallel circuit are applied to the problem of voltage and current relays.

Physics Today — Engineering tomorrow

The development of the magnetron is a typical story of a device which has passed down the technical “production line” from a principle of physics through engineering development to an operating device. This example illustrates not only the infinite possibilities that exist in the field of science, but the fact that the development of these possibilities is a process which transcends the efforts of any single individual or organization.

A future for physicists in industry

One of the things that characterizes the trend of industrial research since World War II is the increasing demand for physicists in a great variety of industrial laboratories. Unlike the chemist, whose important role in industrial technology has long been recognized, the physicist is a relatively new figure on the industrial scene. Thus, it is timely on the occasion of the twenty‐fifth anniversary of the American Institute of Physics to examine the present status of the industrial physicist and to assess his opportunities for the future.

The science of commonplace things

The old fable, “Acres of Diamonds,” teaches that one should not go abroad seeking diamonds, until one has carefully examined ones own backyard. In research, too, the moral applies. Under the scrutiny of modern science, everday phenomena have been made to yield, not only actual man-made diamonds, but “gems” of knowledge of even greater value.

Karl Taylor Compton — Hoover medalist for 1950: Karl Taylor Compton: Scientist, educator, humanitarian

The Hoover Medal for 1950 was awarded to Karl Taylor Compton, Chairman of the Corporation of Massachusetts Institute of Technology. The medal is a joint award of the AIEE, The American Society of Mechanical Engineers, the American Institute of Mining and Metallurgical Engineers, and the American Society of Civil Engineers; Doctor Compton is the 12th recipient of this medal “to a fellow engineer for distinguished public service.”

Development of useful power from nuclear fission

THE DEVELOPMENT of nuclear fission as an important source of useful energy is one of the great scientific and technological challenges of the world today. Here is a source of energy which is potentially capable of supplying the worlds needs for hundreds of years; yet the problems of developing and proving the technical feasibility and economics are beset with peculiar difficulties, for the solution of which very little precedent exists. First and foremost is the problem of secrecy and security. The fuel for nuclear power plants is also the explosive material of atomic bombs, and the consequences of this fact have a far-reaching effect on every aspect of the task. The political problems of atomic energy are, of course, paramount, but this article will be confined to the scientific phases of the problem.