Our studies have been made on the relative spectral distribution over a visible region of coiled fi lament tungsten lamps compared with M-shaped coiled filament lamps. In three laboratories, precise measurement was made with a significant variety of lamp types. All data obtained were reduced into specific curves against the graybody distribution.
General standard lamps for luminous intensity and also tungsten-halogen lamps having a single coil and coiled coil filament showed almost unique distribution. This was noted to be the same as that of the M-shaped lamp. A small discrepancy was observed in the shortest wavelength region between the samples and M-shaped lamp. The lower values in the M-shaped lamp were found to have been resulted from the larger absorption of its glass bulb. The type “JC” small projection lamp was the only exception in this case. It has a rather rough and scattered distribution similar to that of the ribbon filament lamp.
This paper also presents the numerical analysis and further discussion on the overall emissivity of the coiled filament.

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In the previous paper, the authors treated “Discharge Lamp Operation by Means of a Thyristor Inverter Type of Step-up Voltage Circuit”. The advantages of the new lamp operating system are based on the step-up function, the current limit function and controllability of a thyristor inverter type of step-up circuit. These characteristics, however, are realized only when the specified conditions, that is, circuit constant and driving frequency, are satisfied. So, before the design for practical use of the system is begun a detailed analysis of the circuit is required.
Though the analysis of a single phase thyristor inverter circuit itself has been already reported in many literatures, there is nothing directly available for the purpose to make clear a series of the operations of the thyristor inverter type of step-up circuit for the discharge lamp operation.
Thus, the authors have analized the circuit in the frequency domain (400 Hz-) in which the lamp load can be assumed to be an equivalent constant resistance when the fluorescent lamp is used as the discharge lamp. The results have revealed quentitatively the whole mechanism of the lamp operating circuit and given the prospects of the practical circuit design method.

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