Open source PCB layout CAD---KICAD

OPEN source software:
  http://kicad.sourceforge.net/wiki/index.php/Main_Page

PCB lib download web site:
http:// www.kicadlib.org/

最猛太陽風暴

近十年來最大太陽風暴襲擊地球
2012/1/26

一起自2003年十月以來，最強烈的太陽風暴這幾天影響地球，各相關機構都在密切注意，各大航空公司也視情況決定是否改變航線。

美國國家海洋暨大氣管理局表示，由於太陽質子密度增強，因此管理局會對航空公司、人造衛星及相關產業發布警訊。而各大航空公司也將根據美國海洋大氣管理局公布的數據，調整班機航線。

為DC/DC轉換器選擇正確的電感器與電容器

為DC/DC轉換器選擇正確的電感器與電容器 

隨著便攜式電子產品的體積在不斷縮小，其複雜性同時也在相應的提高。這使得設計工程師麵臨的問題越來越多，如電池使用壽命、占板空間、散熱或功耗等。本文以德州儀器TPS6220x係列降壓穩壓器為例，向設計工程師介紹在權衡解決方案的占用空間、性能以及成本時，如何為轉換器選擇正確的與。

　　隨著手機、PDA以及其它便攜式電子產品在不斷小型化，其複雜性同時也在相應提高，這使設計工程師麵臨的問題越來越多，如電池使用壽命、占板空間、散熱或功耗等。

　　使用DC/DC轉換器主要是為了提高效率。很多設計都要求將電池電壓轉換成較低的供電電壓，盡管采用線性穩壓器即可實現這一轉換，但它並不能達到基於開關穩壓器設計的高效率。本文將介紹設計工程師在權衡解決方案的占用空間、性能以及成本時必須要麵對的常見問題。

Pads 2005 教學(含pads logical 和pads PCB)

包含下列課程
Pads 2005
chap 0 pads  layout 概論
pads 2005 八小時課程 01-19(19部影片)
pads layout

PLL 用於金屬探測 ---NE565

PLL脈衝產生電路(74HC4060、TC9122P)

超音波接收器(567)

基於鎖相回路(PLL)的低頻正弦波產生器設計

關鍵字： 鎖相環  壓控振盪器  ICl8038  MC145151-2  PLL 

本文探討了用鎖相技術來產生高頻率穩定度的低頻訊號的方法，並介紹了由ICL8038和MC145151-2構成的低頻鎖相環函數產生器的設計。該正弦波輸出訊號的頻率穩定度可達到10^-8，輸出頻率由所選用的晶振頻率以及MC145151-2的分頻數決定。


正弦波產生器的應用很廣泛，但是適合於低頻範圍內的高穩定度正弦波電路比較少。下表是幾種主要的正弦波產生方法的比較。

從上表中可知，僅採用某一種正弦波產生方法很難實現頻率穩定的低頻正弦波產生器。本文嘗試採用鎖相環來實現頻率穩定的低頻正弦波產生器的設計方法，得到了一種基於MC145152－2和ICL8038晶片的低頻鎖相環函數產生器。這種低頻鎖相環函數產生器的穩定度和準確度與基準頻率相當，不產生額外的誤差。

壓控波形產生器與鎖相環電路

EagleCad Tutorial Lesson (CAD 軟體教學)

EagleCad Tutorial Lesson (CAD 軟體教學)

Lesson1 ~  Lesson11

MSP430 16-bit Microcontroller Code Examples and Function Library

MSP430 16-bit Microcontroller Code Examples and Function Library

     Code examples are available for every MSP430 device that configures each of the integrated peripherals for various application needs. Each zip file below includes both C and assembly code examples that can be directly imported into IAR or CCS. Developers may use the code examples "as-is" or modify the various code modules to jumpstart custom applications. Check the readme to see the complete list of available code snippets along with brief descriptions. Please read applicable section under terms of use prior to utilizing any software. Happy coding!

Parallel Port Pic Programmer for ICSP (Printer port 界面PIC燒錄器)

Parallel Port Pic Programmer for ICSP

My faithful programmer bit the dust, so I needed a programmer to work with my  system. I do not have USB on this machine, so the simplest way to go was to build what was needed. This is the result of that very specific need. I do not need to program anything that is not in the 16F family and all my projects are designed to use ICSP. I had all the parts on hand, left over from a "No Parts Pic Programmer" from many years ago.

Serial Port PIC Programmer (PIC 串列埠燒錄器)

Serial Port PIC Programmer  
 

The PIC programmer presented here uses PC's serial port for communication between the programming software and simple PIC programmer hardware.

Here is the list of currently supported flash devices from Microchip PICmicro 12F and 16F product lines: 12F629, 12F675, 16F627, 16F627A, 16F628, 16F628A, 16F630, 16F648A, 16F676, 16F72, 16F73, 16F74, 16F76, 16F77, 16F737, 16F747, 16F767, 16F777, 16F83, 16F84, 16F84A, 16F87, 16F88, 16F818, 16F819, 16F870, 16F871, 16F872, 16F873, 16F873A, 16F874, 16F874A, 16F876, 16F876A, 16F877 and 16F877A.

SMD 電阻 電容 電感 marking code

How to calculate the value of an SMD resistor

Most chip resistors are marked with a 3-digit or 4-digit code -- the numerical equivalent of the familiar color code for through-hole components. Recently, a new coding system (the EIA-96) has appeared on precision SMDs.

The 3-digit code

Standard-tolerance SMD resistors are marked with a simple 3-digit code. The first two numbers will indicate the significant digits, and the third will be the multiplier, telling you the power of ten to which the two significant digits must be multiplied (or how many zeros to add). Resistances of less than 10 ohms do not have a multiplier, the letter 'R' is used instead to indicate the position of the decimal point.

3-digit code examples:

220 = 22 × 10⁰ (1) = 22Ω (not 220Ω!)
471 = 47 × 10¹ (10) = 470Ω
102 = 10 × 10² (100) = 1000Ω or 1kΩ
3R3 = 3.3Ω

more 3-digit SMD resistor examples...

徹夜用省電燈泡 當心罹乳癌

     徹夜開燈與罹患乳癌的關聯早在十餘年前已被發現，但以色列海法大學生物學教授海姆近期研究指出，開燈睡覺者罹患乳癌的機率，比沒有開燈者高出22%。這項數據比之前的研究高出甚多，究其原因，他認為是人們逐漸換用省電燈泡所致。