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1.
化工控制回路中调节器作用方向判断是《化工自动化及仪表》课程中的教学难点。在化工控制回路中判断调节器作用方向时，可根据回路中负反馈环节个数来确定，当形成回路负反馈时。反作用方向的环节数应为单数个。 相似文献
2.
第二章 放大电路中的反馈 一、反馈的类型与作用 1.按反馈极性分为正、负反馈,用瞬时极性法判断。按交直流性质分为交流反馈和直流反馈。 2.按反馈网络与输出回路的连接方式分为电压反馈和电流反馈,按反馈网络与输入回路的连接方式分为串联反馈和并联反馈。要求掌握四种连接方式的概念,判别方法及作用。 相似文献
3.
“反馈”是电子学中常用的术语。从提高或降低电路的增益情况来看,反馈可分为正反馈和负反馈。把放大电路的输出回路中某一个电量的一部分或全部送回到输入回路中,可以提高放大倍数的叫正反馈,而降低放大倍数的叫负反馈。 对于反馈在电子工程中的作用,可以从不同角度来理解。从提高电路的放大倍数的角度来看,引入正反馈为好。不过,引入正反馈常常会出现放大器自激,使放大器工作不稳,而引入负反馈虽然放大器的放大倍数降低了,但能使放大器的工作稳定,道频带加宽,音质得到改善,因而从提高电路的稳定性这个角度来说,引入负反馈为好。 反馈对电路的输出和输送能起调节和控制作用。控制输纽向被控制对象输入信息,反过来又可以从被控制对象方面获得反馈信息,然后再对电路的输出和输送加以调节和控制。 事物的运动都是有一定规律的。不同事物的运动规律,有些是彼此相通的,因而也是可以互相借鉴的。目前反馈这个概念,已经被广泛地用于社会科学领域。我们进行教学改革,也可以从反馈的作用中借鉴某些有益的东西。那么,反馈具有什么作用?我们在教学中应该从哪些方面加以借鉴呢?根据体育课的具体情况,下面谈谈我的一些想法。 相似文献
4.
0 引言在电子线路中,负反馈得到了广泛的应用,它可以改善放大器的性能,如提高放大器的稳定性,减小非线性失真,抑制噪声,扩宽频带和控制输入、输出阻抗等.一般来讲,一个负反馈放大器由基本放大器和反馈网络两部分组成.根据反馈网络与基本放大器在输出、输入端连接方式的不同,可将其分为4种典型类型,即:电压串联负反馈、电压并联负反馈、电流串联负反馈和电流并联负反馈.怎样对某一具体电路的负反馈类型进行判断呢?我们通过对实例进行分析,找出规律,归纳出一种简单易行的直观判断方法.1 负反馈类型的判断方法从放大器的输出端看,反馈信号取… 相似文献
5.
金轶锋 《渭南师范学院学报》2014,(7):12-15
在电压负反馈的基础上,给发电机、电动机换向绕组两端并联电阻R1,用以检测主回路电流I,从R,取出它的一部分电压作为电流正反馈信号加到扩大机控制绕组CII上．当电压负反馈系数αV增大时,电流正反馈系数α1也要增大,从而提高了发电机的端电压,补偿了电动机因负载变化而造成的转速降,保证了系统具有较硬的静特性． 相似文献
6.
在双闭环直流调速系统中,当电枢回路的电流断续时,由于系统参数的变化,使系统的调速性能变坏,严重时导致系统不稳定.在系统中使用电流自适应调节器可以使调节器的结构和参数自动随系统参数的变化而变化,来改善系统的性能. 相似文献
7.
负反馈是放大电路中被广泛采用的一项技术。本文从反馈网络、反馈极性、反馈组态等方面对负反馈电路进行了全面分析,并得出了判断负反馈的方法和技巧,提出快速判断方法、快速判断反馈的记忆口诀。 相似文献
8.
负反馈是放大电路中被广泛采用的一项技术。本文从反馈网络、反馈极性、反馈组态等方面对负反馈电路进行了全面分析,并得出了判断负反馈的方法和技巧,提出快速判断方法、快速判断反馈的记忆口诀。 相似文献
9.
李永生 《宿州教育学院学报》2001,(3):96-98
多年的教学中,发现学生对掌握交流负反馈类型的判断比较困难。单从概念上理解又较抽象难掌握,但还必须判断出交流负反馈的类型,才能理解交流负反馈对放大器交流性能的改善。现就分立元件构成放大器、运放构成放大器,引入交流负反馈的四种组态如何准确、迅速判断交流负反馈的类型的方法作一介绍。 相似文献
10.
杨建峰 《兰州石化职业技术学院学报》2006,6(3):23-26
MOORE353智能调节器具有强大的控制功能,在现代企业中应用广泛.阐述了使用MOORE353进行复杂批量程序的编程组态方式和结构,以及MOORE353回路的分配等问题.经过编程组态,MOORE353能进行反馈回路控制和复杂的批量生产过程控制,减轻了的劳动强度,提高了操作可靠性.开发的控制方案适于在中、小型的生产装置中大量推广. 相似文献
11.
在对行为金融理论和实证检验结果进行重新分析的基础上,认为市场反应不足、反应过度和泡沫现象都是正反馈过度反应,只是程度、性质不同;＂市场反应不足＂是一次正反馈过度反应,反应过度是一系列同方向的正反馈过度反应,泡沫现象是一系列长时间正方向的巨大正反馈过度反应.正反馈过度反应普遍存在的主要原因是市场中正反馈交易者的广泛存在和＂赚钱效应＂的驱使. 相似文献
12.
薛勇锋 《西安文理学院学报》2006,9(1):83-85
光通过受到超声波扰动的介质时会导致光传播方向的偏转和衍射光强的调制，即声光效应．利用声光效应可以方便而有效控制光束的传播方向，而衍射光相对入射光的偏转角是一个很重要的物理量,就其计算方法进行探讨，推导了偏转角Ф的计算公式，并对计算结果进行误差分析． 相似文献
13.
This study examined the effect of peer assessment on prospective teachers’ performances in complex problem solving. This study also investigated how feedback functions, agreement with peer feedback, and feedback direction affected the use of feedback. The participants included 68 prospective teachers enrolled in the Teaching Methods-2 course during 2012–2013 spring semester and 14 prospective teachers pursuing MA studies on Computer Education and Instructional Technology. The data included prospective teachers’ case solutions and MA students’ feedback reports. The results indicated that groups in both feedback and non-feedback conditions improved on developing solutions for the problems. Additionally, the results showed that while feedback function and feedback direction predicted the use of feedback, prospective teachers’ agreement with feedback was not related to the feedback use. Suggestions were made for further research in line with the findings. 相似文献
14.
Paul J. Mensink Karen King 《British journal of educational technology : journal of the Council for Educational Technology》2020,51(1):10-22
We used educational data mining to quantify student access of online feedback files and explore the underlying drivers of feedback file access in a learning management system (LMS). We collated LMS access logs for 32 individual pieces of assessment representing 1462 feedback files for 484 students (males = 45%, females = 55%) that originated across three undergraduate years, from 20 different degree pathways. Over a third of assessment feedback files (38%, 553 files) were never accessed by students. When students could obtain their assessment mark without opening the associated feedback file, 42% of feedback files were not accessed by students (513 of 1224 files). When assessment marks were integrated into the feedback file (and not reported within the LMS), the proportion of unopened feedback dropped significantly to only 17% of files (40 of 238 files). We uncovered strong gender-specific differences in how students accessed feedback within the LMS that were dependent upon academic performance and the integration of marks within the feedback file. Poorly performing males were less likely to access feedback; however, integrating marks into the feedback files meant that males were over 27 times more likely to access the feedback file. In contrast, females exhibited a much weaker and more variable response to marks being reported within feedback files. Assessments with deadlines earlier in the semester were also viewed more often than those later in the semester. 相似文献
15.
When an adolescent receives critical feedback from adults on what they should change, they may feel discouraged; however, such feedback can be key to learning. This study explored how adolescents attending project-based youth programs experienced critical feedback from adult leaders and the strategies these leaders employed when providing feedback. Qualitative analyses of interviews with 49 youth and 24 leaders indicated that youth participants found critical feedback to be useful because leaders intentionally provided straightforward, clear, and balanced feedback in a manner that was empathetic and involved dialogue that privileged participants’ ownership of their work. Using extant literature, we discuss why the features identified may be especially important during the period of adolescence. 相似文献
16.
Brian E. Clauser David B. Swanson Polina Harik 《Journal of Educational Measurement》2002,39(4):269-290
Cut scores, estimated using the Angoff procedure, are routinely used to make high-stakes classification decisions based on examinee scores. Precision is necessary in estimation of cut scores because of the importance of these decisions. Although much has been written about how these procedures should be implemented, there is relatively little literature providing empirical support for specific approaches to providing training and feedback to standard-setting judges. This article presents a multivariate generalizability analysis designed to examine the impact of training and feedback on various sources of error in estimation of cut scores for a standard-setting procedure in which multiple independent groups completed the judgments. The results indicate that after training, there was little improvement in the ability of judges to rank order items by difficulty but there was a substantial improvement in inter-judge consistency in centering ratings. The results also show a substantial group effect. Consistent with this result, the direction of change for the estimated cut score was shown to be group dependent. 相似文献
17.
本研究调查了计算机辅助反馈策略对大学技术教育课程的影响。具体来说,研究探讨了计算机辅助反馈策略"对错反馈"(Knowledge of Responses,简称KCOR)和"正确答案反馈"(Knowledge of Correct Re-sponses,简称KCR)的有效性,并与"无反馈"(No Feedback)的学生的学习态度进行了比较。三组学生被分配到三个条件之一:KOR,KCR和NR(对照组)。通过四个星期的基于网络的教学实验,研究者获得学习者对计算机辅助反馈教学系略的态度。结果表明,学生对三种反馈显示出相同的态度。计算机辅助反馈策略可能是促进学习的可行的选择。 相似文献
18.
Jonas Flodén 《Assessment & Evaluation in Higher Education》2017,42(7):1054-1068
Receiving feedback from students has become a normal part of life for university teachers worldwide. This puts pressure on them from several sides and may be an influential factor that leads them to tailor their teaching to students’ preferences. The aim of this study was to investigate teachers’ perceptions of student feedback and how it affects their teaching choices. A survey was sent out to all teachers at the School of Business, Economics and Law at the University of Gothenburg, Sweden. The study found that student feedback is perceived positively by university teachers, has a large impact on their teaching and helps improve courses. Student feedback pushes teaching in the direction of fewer lectures and more tutorials, seminars and case studies. Teachers receiving negative student feedback experience more negative feelings related to the feedback, and are also more likely to introduce unjustified changes to their teaching in order to please students. These teachers also tend to have less teaching experience. However, a very large majority of teachers have a high level of professional pride and integrity and do not make (as they perceive them) unjustified changes to their teaching. 相似文献
19.
本研究旨在探讨同伴互评在翻译教学中的应用效果。研究对象是20 名英语专业高年级的学生。研究者首先对受试进行一定的培训,随后收集同伴互评的相关数据,此后随机挑选6名 学生进行访谈。结果表明：同伴互评行之有效;同伴评论的利用率很高;修改后的译文质量有显著提高;翻译的方向对同伴互评的效果无明显影响;学习者对互评机制持积极态度。将同伴互评应用到翻译教学中来,有利于培养学习者的自主 学习与合作学习的能力,强化校改意识并提高翻译质量,以及促成我国的翻译教学向以过程为取向过渡。 相似文献
20.
Christos N. Moridis Anastasios A. Economides 《British journal of educational technology : journal of the Council for Educational Technology》2012,43(3):489-504
Affective feedback during a self‐assessment test could help induce the learner to an optimal emotional state regarding the learning material. However, there is a lack of experimental evidence concerning the influence of affective feedback during a self‐assessment test. This paper is a step towards this direction. The effect of achievement‐based reward feedback on students' state and trait anxiety was examined. Ninety‐two students participated in an experiment. Half of these students received an applause sound after a correct answer to a question. Results highlight gender differences concerning this emotional type of feedback. 相似文献