场效应管和晶体管(三极管)皆为最常用的元件,弄清楚其原理和功能十分有必要。晶体管的功能之一即为开关,利用其截止特性,实现开关功能。文中动态图片生动的阐述了三极管作为开关的功能以及结型场效应管工作原理,值得闲暇之余淡然回味。 继续阅读“动态图解晶体管开关电路及结型场效应管原理”
Relational Databases ~ Introduction to the Relational Model
A data model is a collection of conceptual tools for describing data, data relationships, data semantics, and consistency constraints. In this part, we focus on the relational model.
The relational model uses a collection of tables to represent both data and the relationships among the data. Its conceptual simplicity has led to its widespread adoption; today a vast majority of database products are based on the relational model. The relational model describes data at the logical and view levels, abstracting away low-level details of data storage. 继续阅读“Relational Databases ~ Introduction to the Relational Model”
Elementary Data Structures ~ Linked Lists I
When our primary interest is to go through a collection of items sequentially, one by one, we can organize the items as a linked list: a basic data structure where each item contains the information that we need to get to the next item. 继续阅读“Elementary Data Structures ~ Linked Lists I”
Elementary Data Structures ~ Arrays
Perhaps the most fundamental data structure is the array, which is defined as a primitive in C and in most other programming languages. We have already seen the use of an array as the basis for the development of an efficient algorithm, in the previous articles; we shall see many more examples in this section. 继续阅读“Elementary Data Structures ~ Arrays”
信号完整性小记 ~ 电容与电感
前文 信号完整性小记 ~ 时域与频域 已对时域与频域分析方法进行了相关阐述,本文对电容与电感的电气模型和物理基础进行论述,以便在实际使用中根据设计需求确定具体参数,达到预期效果。 继续阅读“信号完整性小记 ~ 电容与电感”
电源研发实用经验小结
在前文 反激式开关电源设计解析~(上) 和 反激式开关电源设计解析~(下) 中已对反激式开关电源设计与选型进行了详尽的分析。为了结合实际设计需求,本文将对开关电源工作小技巧进行总结,提高开发效率。 继续阅读“电源研发实用经验小结”
反激式开关电源设计解析~(下)
在前文 反激式开关电源设计解析~(上) 中已对反激开关电源特点、电动自行车电源电路初级侧的原理图以及相关元器件选型进行的详尽的阐述。本文将对次级侧原理图进行论述。
继续阅读“反激式开关电源设计解析~(下)”
反激式开关电源设计解析~(上)
在开关电源市场中,400W 以下的电源大约占据整个市场的70~80%,而其中反激式电源又占绝大部分,几乎常见的消费类产品全是反激式电源。优点:成本低,外围元件少,能耗低,适用于宽电压范围输入,可多组输出。缺点:输出纹波比较大。(输出配合低内阻滤波电容或配合LC噪声滤波器可改善)本文以自行车充电器为例,详细阐述反激开关电源的设计流程及如何进行元器件的选型。 继续阅读“反激式开关电源设计解析~(上)”
Database System Concepts ~ Introduction III
The architecture of a database system is greatly influenced by the underlying computer system on which the database system runs. Database systems can be centralized, or client-server, where one server machine executes work on behalf of multiple client machines. Database systems can also be designed to exploit parallel computer architectures. Distributed databases span multiple geographically separated machines. 继续阅读“Database System Concepts ~ Introduction III”