An investigation of a pulsed Hg arc has been undertaken to test the relation V α I°⁴ between the voltage and current of an arc discharge. Although the experimental V-I characteristic exhibited this tendency, further considerations strongly indicated that the agreement between theory and experiment was probably a coincidence. The Paschen breakdown curve was determined, and together with simultaneous measurements of the current and voltage, it was possible to measure the average column field strength as a function of current. As a result of an unexpected feature of the apparatus, namely an inherent motion of the electrodes, the voltage waveform could be used to obtain an approximate measurement of the combined thickness of the anode and cathode falls df, and also the average field strength in these regions Ef. The measurements df = 3x10⁻⁶ cm, and Ef = 2.4x10⁶ volt/om appear to be in agreement with the field emission theory. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis is concerned with the timing and coincidence circuitry which controls the operation of a time-sharing function generator and four-quadrant analog multiplier. The functions to be generated are fed into the computer in time sequence as voltage waveforms of short duration, A waveform is sampled at a particular value of the independent variable x and the resulting ordinate Ef is normalized with respect to the maximum function ordinate Em and multiplied by a reference voltage Er. The output of the multiplier is then a voltage which represents the expression EfEr/Em and this voltage is channeled through the computer. Multiplication is performed by the following method. Two voltages E₁ and E₂ are simultaneously applied to two identical linear networks whose response to unit voltage is N(t). The outputs are then E₁N(t) and E₂N(t). If, on comparing E₁N(t) with a reference voltage E₃, the second sweep E₂N(t) is clamped at the instant of equality, then N(t) = E₃/E₁ and the output is E = E₂N(t) = E₂E₃/E₁. The present proposal is to generate the functions optically. A function is graphed, photographed on 35 millimeter film, and mounted on the rim of a rotating disc. The optical system projects a narrow segment of the function onto a phototube and its output, biased for the zero level, follows the function ordinate in a strict voltage analog sense. The full abscissa scale is represented by a constant voltage and the input specifying the sampling point is some fraction of this full-scale voltage. In order that the sampling point x be independent of the velocity of the scanning disc the coincidence circuitry eliminates velocity as a variable in the selection of x. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In this dissertation, positive-real conformal transformations are used to develop synthesis procedures for the realization of driving-point immittance functions by exponentially- tapered distributed RC networks. These synthesis procedures include the realization by uniform distributed RC networks as a special case. New equivalent circuits are developed for the exponentially- tapered distributed RC network. These differ from the equivalent circuits for the uniform distributed RC network through the presence of positive and negative lumped elements and ideal transformers. It is found that the lumped elements must be eliminated from the equivalent circuits developed for exponentially tapered distributed RC networks before it is possible to apply a positive-real conformal transformation to change the synthesis problem into a lumped LC synthesis problem. Hence, through Richards Theorem, a cascade synthesis procedure for the realization of driving-point immittance functions is developed. Various cascade network realizations are presented. Additional distributed RC sections are used in these realizations to compensate for the lumped elements in the equivalent circuits. Before the synthesis procedure can be applied, it is necessary to approximate any specified driving-point immittance function by a function that is realizable by one of the network configurations presented. A digital computer with plotting facilities is deemed necessary for this purpose. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In the conventional joints for aluminum core steel reinforced (A.C.S.R.) conductors the path of the electric current in the outer strands passes through two mechanical contacts, while for the inner strands the number of contacts is considerably more. It is recognized that the present techniques of making compression Joints is considered by many to be satisfactory. However, it is obvious that a continuous metal Joint would be superior. Recent advances in welding make the construction of such a Joint possible. In the Joints constructed for experimental purposes each strand of a 397,500 C M conductor was brought out between two aluminium sleeves and Heliarc welded. In the finished Joint the weld bonds the inner and outer sleeves and the Individual conductors. The ends of the joint are compressed to prevent ingress of moisture which may be injurious to the conventional steel compression sleeve which connects the steel cores together. Tests of the Individual strand resistance as measured between the central part of the Joint and the strands showed the strand resistances to be uniform and equal to an equivalent length of strand. This shows that each strand was satisfactorily connected at the weld. Overall resistance, heat and mechanical tests indicate that the welded-compression joint should be satisfactory in the field. In addition to the welded-compression joint two cast-aluminium Joints were also investigated. These, however, due to poor bonding were found unsatisfactory. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The propagation of the switching surge wave front on multiphase power lines was investigated by modal analysis and conventional Fourier Transformation. A 500 kV untransposed, three-phase transmission line, for which field test results were available, was chosen as a test case. Phase A of this test line was excited from a double exponential voltage source and the voltage response at the receiving end was calculated and measured in all three phases. The calculated voltage arrival time matched closely the measured value, and was very close to the time taken by electromagnetic waves in air at a speed of 0.3 km/μs. The calculated voltage response curves also came close to the measured results (errors within 8%). / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Thesis (M.Sc.)--University of Hong Kong, 1993. / Also available in print.

Thesis (M. Sc.)--University of Hong Kong, 1993.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Michigan, 1937. / Lithoprinted. Errata slip attached to front fly-leaf. Bibliography: leaves 106-107.

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