聚吡咯在铝电解电容器中应用

报告由水溶性的APS作为氧化剂、NaDBS作为表面活性剂、p-NPh作为掺杂剂制备的PPY材料的多种电性能,采用SEM观察PPY表面形貌,发现大尺寸磺酸根离子的共存会降低PPY的颗粒尺寸,添加p-NPh提高PPY主链规整度进一步增加PPY的电导率,筛选出应用于卷绕式铝电解电容器的PPY最佳配方.     

Hybrid organic-inorganic electrolytic capacitors

Organic capacitors are among the most significant applications of conductive polymers, allowing the realization of lightweight and flexible dispositives. The main drawback of completely organic capacitors is the very low dielectric rigidity, due to the irregular surface of the polymer-polymer interface. This paper describes our hybrid solution using aluminum electrodes, with the very important characteristic of easy connection between contacts of the discrete dispositive and electrodes. Chemical, technological, and functional tests have been conducted to estimate the effective values of this device, and natural properties of self-healing and nonpolarity have been investigated.     

氯离子对电解电容器耐久性的影响

针对耐久性试验中电解电容器多次发生炸裂、失效的问题,通过对不同温度、氯离子含量条件下,电容器的耐久性试验,考察了电容器的失效时间。结果表明,试验温度越高,氯离子含量越高,电容器失效就越快。电容器的失效对高温更为敏感,极微量的氯离子导致电容器提前失效。在105℃,1 200 h的条件下,氯离子含量超过1 ppm电容器就会在耐久性试验中失效。     

Reliability comparison of tantalum and niobium solid electrolytic capacitors

This paper deals with a comparative investigation of tantalum and niobium solid electrolytic capacitors. Nb is an attractive replacement for Ta in solid electrolytic capacitors because it is lighter and cheaper than Ta. Although these two metals have much in common in their crystalline structure and physical and chemical properties, the electrical properties of Ta and Nb capacitors are different. Particularly, most Nb capacitors are characterized by an increase in direct current leakage during life testing. This causes parametric failure of Nb capacitors. On the other hand, the direct current leakage of Ta capacitors does not change significantly for a long time, but then increases sharply for some samples. Hence occasional catastrophic failures are typical for Ta capacitors. Nevertheless, the properties of high-CV Ta capacitors with low and high rated voltage approach the properties of Nb capacitors. The physical nature of these phenomena is discussed. © 1998 John Wiley & Sons, Ltd.     

1/f noise of electrolytic capacitors as a reliability indicator

The electrical noise of capacitors and the relationship between typical imperfections in capacitors and their excess noise are described. It was assumed that a noisy capacitor is a poor-quality one. Investigations were aimed at the determination of a correlation between the inherent noise of capacitors and their reliability (time to failure) and also at the determination of an indicator to predict reliability. Investigations (noise measurements and reliability tests) were carried out on two samples of aluminium electrolytic capacitors. The method of reliability prediction for electrolytic capacitors based on their low-frequency noise is described. For reliability prediction the noise intensity G at a frequency of 2 Hz was used as a reliability indicator. It was found that the evaluated correlation coefficients between the noise parameter G and the time to failure, t, are statistically significant. It is concluded that it is possible to predict the lifetime of aluminium electrolytic capacitors on the basis of their 1/f noise. © 1998 John Wiley & Sons, Ltd.     

Generalized analysis of multiport microwave measuring circuits

A generalized mathematical model of a multiport measuring device is used as the basis for examining methods for measuring microwave circuit parameters and the design principles of multiport systems. The ideas behind searching for promising measurement methods are presented. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 55–58, June, 1998.     

The errors of differential balanced measuring circuits

Conclusions We have estimated the mean-square errors of two forms of balanced differential measuring circuits differing in respect of the positioning of the executive organ.We have determined the optimum values of the parameters of the balanced circuits minimizing the measuring error. We have shown that for incomplete correlation between the random variations of the signals being compared the optimum setting of the circuit differs from that usually employed. We have made a comparison between the minimum errors of unbalanced and balanced measuring circuits and have calculated the gain in accuracy obtained on replacing an unbalanced measuring technique by a balanced one. We have found that, for low modulation indices of the probing signal representing the quantity being measured, the use of a compensated measuring circuit instead of an unbalanced one does not increase the measuring accuracy and is therefore undesirable.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 24–26, January, 1975.