摘要:

A brief description is given of the rectifier substations recently constructed on the Underground Railways of the London Passenger Transport Board.Following upon this, the experience that has been gained in the operation of the rectifier plant is outlined, some indication then being given of the general maintenance required in the rectifier substations.

DOI:10.1049/jiee-1.1936.0023

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0028

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0029

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0030

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0031

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0032

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0033

出版商:IEE    

年代:1936

数据来源: IET

摘要:

Receiver performance has in the past been limited by inadequate audio-frequency range (50–5 000 cycles per sec.) and inadequate range of volume levels. The paper describes a radio-gramophone in which alternative upper frequency-limits of 3, 5, 7, and 8 kilocycles per sec. are provided, and the range of volume levels is increased by including a form of “negative automatic volume control” in the audio-frequency amplifier.The first section of the paper summarizes the requirements of the new radio-gramophone, which include radio-frequency, intermediate-frequency, and audio-frequency circuits each of adjustable and width. The radio-frequency section includes amplified automatic volume control and a selective quiet tuning and indicating circuit. For gramophone reproduction a new pick-up and needle, with a cut-off frequency of 8 000 cycles per sec., are described, together with a motor giving extreme constancy of speed. For the final acoustic reproduction, an improved electrodynamic loud-speaker is described having a paper cone with a metallic centre portion to give good reproduction up to 8 000 cycles per sec.Circuit diagrams and performance characteristics of the individual sections of the receiver are illustrated, and the paper concludes with a series of acoustic frequency-response curves taken under various conditions.

DOI:10.1049/jiee-1.1936.0035

出版商:IEE    

年代:1936

数据来源: IET

摘要:

The paper describes a high-speed continuously-evacuated cathode-ray oscillograph for the recording of high-voltage transients; the distinctive feature of the instrument is that impulsive voltages of 100 kV to earth may be applied directly to either deflection plate singly, or +100 kV to one and − 100 kV simultaneously to the other, without the use of a potential divider. The reasons for. and advantages accruing from, the use of such an oscillograph are discussed, with particular reference to the distortion inherent in the use of potential dividers. Precautions to be observed in the operation of the high-voltage plates are described, reference being made to the means of producing the high vacuum required in the tube.A circuit producing a delayed high-voltage impulse is shown, and the possibilities of the instrument are demonstrated by a brief investigation of the characteristics of a sphere-gap when sparking over on the front of a steep-fronted wave.

DOI:10.1049/jiee-1.1936.0038

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0039

出版商:IEE    

年代:1936

数据来源: IET