摘要:

As the length of submarine telephone-cable systems is increased, new demands are placed on the amplifying valves used in the submerged repeaters. Based on the experience of earlier valves suitable for shallow-water repeaters, two new valves have been developed for deep-water submarine cables.

DOI:10.1049/pi-b-2.1960.0094

出版商:IEE    

年代:1960

数据来源: IET

摘要:

A major change that has occurred in high-power transmitting valves during the last decade is the introduction of the thoriated tungsten filament or cathode. The paper describes the technology of these cathodes and some of the valve characteristics resulting from the change-over from a pure tungsten cathode. Details are given of the various properties of thoriated tungsten cathodes resulting from the carburization process which is necessary to give stable emission. The performance is given of six typical types of transmitting valves used both in the sound and television services of the B.B.C. These are typical of many other types of large valves with thoriated cathodes which differ only in minor aspects from those described. Detailed performance results are given, together with a study of the economies of thoriated cathodes in practice. In considering the installation of these valves in place of the valves using bright tungsten cathodes, consideration has been given to the economic aspects of installation. Illustrations of the six types of valves described in the paper and survivor curves both for tungsten and thoriated tungsten valves are given, together with the curves showing loss of programme due to valve failure.It seems clear from the results that not only do thoriated tungsten filaments or cathodes give economy in operation, but the lives in many cases are considerably extended.

DOI:10.1049/pi-b-2.1960.0095

出版商:IEE    

年代:1960

数据来源: IET

摘要:

To increase the accuracy of the trajectory tracer improved methods of field determination on the resistance network have been investigated. One of these—an interpolation system applicable to axially symmetric fields—is described. This system has been constructed, and some results obtained with it for trajectories through an electron lens are given. These are compared with corresponding results obtained without the interpolation device and with results obtained by other methods.It is seen that the interpolation system provides significantly increased accuracy for this particular type of problem, with little extra complication in the operation of the trajectory plotter.

DOI:10.1049/pi-b-2.1960.0096

出版商:IEE    

年代:1960

数据来源: IET

摘要:

All measurements of capacitance and resistance at the N.P.L. depend ultimately upon the Campbell standard of mutual inductance and upon frequency. Hitherto capacitance has been obtained from mutual inductance and resistance using a Carey-Foster type of network. The precision obtained with this in the Astbury bridge has been considerably improved since it was constructed 20 years ago, and an accuracy of repetition of about five parts in 106is now obtained. Capacitance can also be derived from resistance and frequency; a Wien bridge has recently been constructed for this purpose. It has been designed to make a single precise measurement of capacitance (the repetition accuracy is two parts in 106) and thereby to complete a system of three measurements relating capacitance, resistance and mutual inductance in conjunction with frequency.

DOI:10.1049/pi-b-2.1960.0097

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The logical behaviour of a basic ferroresonant circuit is described. A procedure for obtaining the ‘and’ and ‘or’ fundamental circuits through ferroresonant elements is reported. The possibility of coupling these fundamental circuits allows the development of a ferroresonant system of circuit logic. A ferroresonant inhibit circuit as well as the simplification it permits in the logical system are studied. The results obtained are described.

DOI:10.1049/pi-b-2.1960.0098

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The impedance/frequency characteristics of some cold-cathode glow-discharge tubes over the frequency range 300c/s-5 Mc/s have been obtained. The results are shown to agree with an extended form of theory by van Geel. Impedance measurements indicate that there are several delayed effects in the glow discharge which affect the low-frequency impedance characteristics considerably. Tentative suggestions about the origin of these effects are discussed and the influence of some tube parameters on the magnitudes of the consequent delay times are indicated. The equivalent circuit of the glow-discharge tube is determined from the results.

DOI:10.1049/pi-b-2.1960.0099

出版商:IEE    

年代:1960

数据来源: IET

摘要:

Cyclic fluctuations of temperature in an enclosure with a simple on-off control system are discussed. It is shown that such a system can be improved by using two control elements completely immersed in the fluid of the enclosure, and therefore not subject to datum error. The output signal of one of the control elements is required to have a lagging phase angle, and a theoretical analysis is made in which the thermal frequency responses of various configurations are compared. Conclusions are reached about the relative merits of different configurations, and a description is given of the application of the theoretical principles to an experimental temperature-controlled enclosure.

DOI:10.1049/pi-b-2.1960.0100

出版商:IEE    

年代:1960

数据来源: IET

摘要:

When a sinusoidally varying p.d. is applied between the electrodes of an ion chamber subject to ionizing radiations, the motion of the charge carriers and the form of the current in the external circuit depend upon the applied voltage and frequency, the gas filling and the flux level.A brief analysis of such conditions is made with space-charge effects neglected and is then modified semi-empirically to take account of space-charge phenomena. In the course of this analysis a definition of ‘saturation’ as applied to chambers using alternating polarizing voltages is proposed, and a series of experiments is described showing how variations in the aforementioned parameters affect this condition. Throughout the tests a standard A.E.R.E. RC1 ion chamber was used and was irradiated in the reactors Gleep and Bepo.

DOI:10.1049/pi-b-2.1960.0101

出版商:IEE    

年代:1960

数据来源: IET