DOI:10.1049/jiee-1.1930.0052

出版商:IEE    

年代:1930

数据来源: IET

摘要:

This paper describes the practical difficulties experienced and overcome in the development and construction of a type of photo-electric photometer suitable for measuring incandescent electric lamps of the vacuum and gas-filled 10-watt to 100-watt types. The apparatus is capable of measuring lamps at commercial speeds under continuous service conditions. The construction is simple and uses mainly standard component parts.

DOI:10.1049/jiee-1.1930.0053

出版商:IEE    

年代:1930

数据来源: IET

摘要:

This paper describes the principles and development of an ammeter which has been made for measuring current of very high frequencies, such as 30 000 kilocycles per sec. The instrument is of the dynamometer type and has a geometrical form for which all the changes of current distribution can be calculated. The correcting factors approach a limiting value and do not increase contruments. A special feature of the design is that an instrument can be made to carry unshunted a current of any magnitude. This removes all uncertainty about shunting ratio and so the instrument should be more reliable than one in which the current is supposed to divide evenly among a number of resistance wires in parallel.Methods are described for checking the calculated correction factors and there are also some calibrations at frequencies round about 1000 kilocycles per sec. In addition, measurements are described of the high-frequency resistance and of the inductance and terminal capacity.

DOI:10.1049/jiee-1.1930.0054

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper describes the construction and theory of a simple form of hot-wire ammeter intended for use at any frequency up to 100 million cycles per sec. A cylindrical form is adopted in order that the correction factors for various frequencies may be calculated with certainty, and figures are given for an instrument as actually constructed.

DOI:10.1049/jiee-1.1930.0055

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The device the mechanical impedance of which at a given frequency is to be measured is driven by one prong of an electrically-driven tuning fork, and the other prong is loaded to restore balance, the load requirede being the mechanical impedance to be determined. The balance condition is indicated by the absence of vibration of the fork support.An improvement depends upon the experimentally determined fact that mechanical resistance out-of-balance does not appreciably affect the support vibration. If the prongs are balanced for mass, the total resistance can be found from a decay-factor determination or by a single measurement of amplitude with a known current, and the resistance of the device estimated.A measurement is made of the mechanical impedance at 100 cycles per sec. of a certain gramophone pick-up.

DOI:10.1049/jiee-1.1930.0056

出版商:IEE    

年代:1930

数据来源: IET

摘要:

It is a matter of common experience that the performance of the large majority of commercial pick-ups leaves much to be desired. The following notes describe an experimental investigation of the performance of certain types.Further experiments are then described on the mode of vibration of a pick-up armature and on other factors affecting the performance of the instrument.A theoretical treatment based on the results of these experiments is given and finally a new design is evolved.

DOI:10.1049/jiee-1.1930.0057

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The addition of a series inductance of suitable value to the anode circuit of a valve oscillator results in the frequency of the oscillations generated being independent of fluctuations in the valve constants.

DOI:10.1049/jiee-1.1930.0058

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper describes a combination of a projection oscillograph, a special amplifier, and a variable condenser coupled to the rocking mirror of the oscillograph, by means of which response curves can be thrown on to a screen for observation or may be recorded photographically.The amplifier may also be used with the oscillograph in the ordinary way for low-frequency observations, the amplifier then functioning as a special form of valve voltmeter giving an output suitable for operating the oscillograph.

DOI:10.1049/jiee-1.1930.0059

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0060

出版商:IEE    

年代:1930

数据来源: IET