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  1. If you have forgot or lost your password you can use the Lost Password Recovery Form

    On this form you should enter the registered email address for your user account. An email will be sent to that address shortly after entering the details with instructions for resetting your password.

    Since passwords are encrypted, there is no way to resend the original password; this option provides you with the ability to reset your password.

    You must be able to receive emails to your registered email address for this to work. You may need to check your spam filters and folder if you do not see this email shortly after requesting a password reset.

    If you are experiencing problems, please post in the Feedback and Suggestions Forum which allows Guests to post, where an administrator will deal with the issue. Please note, for security reasons, we will not manually send passwords for accounts to any user provided e-mail address - we will only deal with the address registered to that account.

  2. We have added a Videos section to the main All About Circuits site as a compliment to the E-book Volumes and Worksheets. The video lectures were created by by Tim Fiegenbaum of North Seattle Community College and are available on a variety of topics, including:

    • Electronic Systems
    • Basic Electronics and Units of Measure
    • Basic Components and Technical Notation
    • Circuits
    • Circuit Troubleshooting
    • Alternating Current
    • Inductors, Capacitors, Transformers
    • Semiconductor Technology
    • Diodes and Diode Circuits
    • Transistors and Transistor Circuits
    • Op Amps and Op Amp Circuits
    • Digital
    • Microprocessors

    Questions and Answers:

    How do I view the video lectures?

    Navigate to the Videos section on the main site. Select a video to watch and the video will automatically load and play. You can stop and pause the lectures at any point, and scan through the lecture using the scroll-bar.

    Note: the video lectures require the Adobe Flash Player plugin to be installed in your browser; if you don't already have it, you can download it from the Adobe website:

    Are the video lectures available for download so I can use them off-line?

    Sadly not. The videos contain a number of copyrighted images and were posted only through permissions from the publisher. For that reason they are available for viewing but not for download.

    Please let us know if you have any issues with this feature.

  3. Recently I stumbled across a selection of blogs at Matlab Central written by engineers and developers from The Mathworks on the inner workings of Matlab. Described by The Mathworks as:

    The code snippets, workarounds, and general Matlab workings are a real help for anyone who uses Matlab a lot and wants to get the most out of using it.

    Have a look: Matlab Central Blogs

    In particular, I am quite impressed with Steve Eddins Image Processing blog, Steve on Image Processing.

  4. Many web browsers these days have spell-checkers built into them, or can use add-ons to add spell-checking capabilities. However, this is not the standard set-up on the majority of web browsers in use (notably Internet Explorer).

    All About Circuits has spell-checking built into the forums and blogs. On the Post Reply screen or the Quick Reply dialog, select the spell-checker from the formatting toolbar:


    This will open the spell-checker from where you can select corrections for misspelt words:


    For each misspelt word you are able to Change or Ignore the words like you would in any word processor. The spell-checker gives the option for Learning words not currently in your dictionary, and also has a Look-up function if you want to check the meaning of a particular word, and a Thesaurus for looking-up alternative words - checks at Merriam-Webster On-line (see, .

    The spell-checker checks the spelling in English(US).

  5. Previously I blogged about the Socratic Project, a free project of worksheets and questions designed to support the material covered in the AAC e-book.

    Recently the Socratic Project was fully integrated into All About Circuits, available from here. As per the original project the following categories are available:

    1. Basic electricity
    2. DC electric circuits
    3. AC electric circuits
    4. Network analysis techniques
    5. Discrete semiconductor devices and circuits
    6. Analog integrated circuits
    7. Digital circuits
    8. Mathematics for electronics

    We have, however, developed the original concept somewhat. The original Socratic Project was available as downloadable PDF files of the questions and answers. The worksheets section at All About Circuits actually goes one step further, we have implemented a fully interactive system:


    Page Activities - Useful activities for the worksheets including downloadable PDFs of the worksheets a (note: the PDF link is for the worksheet you are currently viewing), print options to enable printing of the worksheet direct from the website, and link and blogging options for a range of services.

    Related Pages on the Site - Gives links to pages that are similar to the current worksheet. These pages may contain information that is relevant for the current worksheet or provide supplementary information.

    Page View History - Provides a history of your recently viewed pages on All About Circuits, including worksheets and e-book chapters.

    The question on the website are fully interactive: under each question there is a Reveal Answer link. Selecting this option opens a frame within the current page:


    The answer to the question is given, including supplementary notes to help the reader understand the concepts analysed in the questions further.

    To remove the answer frame just select Hide Answer.

    This is built on the first version released in August 2008. We are always look at feedback and corrections to the material, so if you see an error or wish to make a suggestion, please post in the Feedback and Suggestions Forum.

    The Socratic Electronics Project is licensed under the Creative Commons Attribution License.

  6. The All About Circuits e-book is published under the terms and conditions of the Design Science License (DSL) which outlines how the material may be used, including how the material may be copied, distributed, and modified.

    The conditions are generally clear and concise, however from time to time there is confusion about how the material may be used, particularly for use in derivatives works.

    Section 3 of the DSL details the conditions for copying and distribution of the material:

    Therefore you are free to use and distribute the material, provided that the full DSL notice is distributed accordingly and that the origin of the material is not misrepresented.

    Furthermore, section 3 details that there are no financial restrictions on the use of the work, provided it adheres to the DSL conditions:

    We must also note the conditions imposed by Section 4 of the DSL on modifications to the work to create derivative works:

    Therefore, you are able to copy, modify, redistribute and charge for use of the material, provided the original source is not misrepresented. There should also be a copy of the DSL accompanying the derivative work to acknowledge the work of the original authors published here at All About Circuits and at

    Please note section 6 of the DSL on the terms of acceptance:

    Therefore use of the material presented here at All About Circuits, in any form, is an acknowledgement of your acceptance of the terms and conditions imposed by the DSL on the work. A link to a locally stored copy of the DSL is located at the bottom of every page in the e-book.

    If you have any further questions about using the material here at All About Circuits, or you want clarification on other aspects of the DSL, then please post in the Feedback and Suggestions Forum and a site administrator or e-book co-ordinator will offer some advice.

  7. Last night Windows Vista SP1 came through on Windows Update following an update to my sound card driver (SP1 had been held off due to a selection of conflicting drivers). Having heard some good things about SP1 I installed it and thus far everything is fine.

    One thing I did notice was that by installing SP1 my hard-drive gained an extra 8GB (yes, you read that correctly 8 gigabytes) in free space!! I am bemused, where has this 8GB come from considering that the SP1 download was 66.9MBs in size! Yes this was a pleasant side affect of SP1...

  8. RSS syndication is enabled here at All About Circuits. This allows you to view newly created threads in guest viewable forums without visiting the board.

    The feeds are currently provided for a range of services, including Google and My Yahoo. Details for individual forums are listed on our RSS Feeds Page. (Note: Updates to this service will be maintained at the above page).

    Most modern browsers have facilities for reading RSS feeds and will automatically detect the availability of feeds on bulletin board pages.

  9. Matlab is a very powerful numerical computing environment which enables the user to perform complex mathematical and scientific function with relative ease. One of the biggest issues with Matlab is the price of it. Students can purchase an un-upgradable version for less than $100 (~£50), however this is only available for students and may only be used during the course of their studies. Commercial licenses are considerably more running into thousand of dollars/pounds depending on how many license-seats are required and what toolbox add-ons are ordered.

    There are two free alternatives that I can recommend:

    1. Octave (see

    Designed with Matlab compatibility in mind, Octave provides a simple command-line focused UI that implements many of the functions of Matlab's M-language. A lot of Matlab M-code will run directly within Octave, although there are incompatibilities, see

    2. FreeMat (see

    FreeMat is a full numerical computing environment in the same mould as Matlab. It has some Matlab M-code compatibility (apparently 95% code compatibility). Actually FreeMat goes beyond the capabilities of Matlab by providing a codeless interface to other programming languages such as C, C++, and Fortran and some IDL functionality. Windows, OSX and Linux platforms are supported (see the FreeMat site for details of versions).


    A third free Matlab alternative that has been recommended on the forums was Scilab (see

    Scilab is a full numerical computing environment similar to Matlab, and although functioning with similar syntax is not fully Matlab compatible (from my initial musing less so that Octave and FreeMat). However, Scilab contains a useful Matlab > Scilab converter to port Matlab M-code into Scilab's own code. Scilab is available for Windows, UNIX and Linux.

    Thanks to Caveman for pointing this one out.

    EDIT (2):

    A fourth Matlab alternative that has been recommended on the forums was R (see Note, R is not a direct Matlab alternative like Octave and Scilab (i.e. M-code is not interchangeable between these applications).

    R is a free numerical computing software environment for statistical analysis and graphics running on Windows, a wide variety of UNIX platforms, and MacOS.

    Thanks to Papabravo for pointing this one out.

  10. (I originally posted this on the forums).

    Matlab is a proprietary numerical computing environment developed by the Mathworks which allows for matrix manipulation and mathematical analysis across a wide range of engineering and scientific disciplines. Through out my time using Matlab I have come across a wide range of site and tutorials that have helped me learn to use Matlab and get the most out of it.

    The following is the first set of links that I have complied for the users here at AAC. The information covered in this section is the Mathworks website, general Matlab tutorials, tips and tricks for using Matlab, debugging in Matlab, and some Matlab FAQs. Note that some websites contain common information, but this is intended to be catch all:

    The Mathworks Website:

    Mathworks Homepage

    Matlab Functions List - this is the same function listing that is part of the Matlab help

    MatlabCentral - Matlab User Community, including the file exchange and link exchange

    Matlab Tutorials:

    Introduction to Matlab

    Getting Started with Matlab

    Helpful Information for Using Matlab

    Matlab Tutorials from MatlabCentral

    Matlab Tutorial from the University of New Hampshire

    Matlab Special Characters

    Matlab Commonly Asked Questions from MIT

    3-day Matlab Tutorial from MIT

    Matlab on Athena at MIT

    Matlab Basics Tutorials

    Plotting Tutorials for Matlab

    Matlab Tips and Tricks:

    Matlab Tips and Tricks

    Matlab Array Manipulation Tips and Tricks

    Exploiting the comma seperated list - article from the Mathworks

    Matlab Tips and Previews

    Matlab Visualisation Tips

    Matlab Programming Tips - PDF article from the Mathworks

    Matlab Debugging:

    Debugging Matlab m-files

    Debugging in Matlab

    Guidelines for Debugging in Matlab

    Matlab FAQs:

    Matlab FAQ from the University of Florida

    Matlab FAQ from Stanford

    Hope this is useful for some of you. Any comments and corrections of broken links are welcome.

  11. A couple of years back we started a thread asking for suggestions for useful websites that members have come across that have helped in all aspects of electronics, from information, learning, software etc.

    The original thread is one of the most viewed threads here at AAC: Useful Websites for Electronics

    A forum member, web, decided to clean up the old thread and categorise the websites by area; thus Useful Websites for Electronics ver.2 was created.

    We ask for members to suggest websites they have found useful, however stipulate several conditions on appropriate suggestion of websites (see here). Please note:

    Suggestion and discussion of websites and books must adhere to the All About Circuits Forum Rules, Code of Conduct and Terms and Conditions of Usage. As a result:
    • Suggestion of websites and books should have relevance to the field of electronics. Off-topic discussion of websites and books should be made in the Off-Topic Forum.
    • All About Circuits does not support any form of commercial advertisment or promotion; therefore suggestion of websites must not advertise any product or service, and suggestion of books must not be a stand alone advertisement. This is in accordance with item 8 of the forum rules.
    • Suggestion of softwares or website services must not impose limitations other than basic and fair feature suppression as interpretted by the Moderator team. An example of basic and fair feature suppression would be a restriction on numbers of components in EDA software, but time restrictions are not permitted in any circumstances.
    • No website or software recommended should have any adverse affect on another forum users computer without exception; this includes, but is not restricted to, malware, phishing attempts etc.
    • To suggest a website that provides free access to information and resources for electrical engineering and electronics should be made in the Useful Websites for Electronics Thread.
    All websites suggested in all threads will be vetted by the Moderator team. In all instances the Moderator team reserves the right to remove or edit and web-based content without reason.

    We hope this will continue to be a useful resource for the members here at AAC.

  12. Many people who use Matlab might not be aware of the File Exchange over at Matlab Central. As described on the Matlab site:

    Files are organised into 26 different categories depending on application. Files include Matlab functions, help files, cheat-sheets, and mini-projects.

    These files are free to download and use in your own Matlab applications and projects. It is worth noting that the functions on the File Exchange are not supported like the core Matlab functions, and may not work as described (if at all). As always the user is expected to test and debug the functions for their specific applications.

  13. The e-book here at AAC is an unfinished and continuous piece of work. We get weekly recommendations for corrections and improvements to the e-book, and as such the e-book relies on the many people who use it to improve the content.

    Although the editing of the final version of the e-book is controlled by the E-book Co-ordinator, we encourage members to contribute to the project in any way they wish; including writing sub-sections through to whole chapters.

    We recently added a comprehensive overview on how to contribute to the AAC e-book. Anyone wishing to get involved in the project should refer to this section of the site and ask any questions they have in the Comments, Feedback and Suggestions Forum.

    Please note the e-book is released under the Design Science License and any work contributed to the project will fall under this license.

  14. Originally I posted this work around on the forums, I have had some positive feedback from the posts so in order to prevent it getting lost on the forums I thought it a good idea to post it up here.

    For those of you that might be using Matlab R2006 onwards there is a bug which means if you start Matlab for the second time in a session (a session is defined as the time between OS reboots), at start-up Matlab gets stuck in the initialisation phase. You can quit with CTRL+C, but none of the paths are set and cannot be manually set from the command line rendering MATLAB useless. The only way to get around this is to reboot your OS and try again.

    Having endlessly struggled with this I have a work around:

    - Close Matlab.

    - Navigate to the Matlab root installation directory (by default C:\Program Files\MATLAB on Windows, and /usr/local/matlab on Linux).

    - Navigate to the toolbox > local folder.

    - Open userpath.m in a text editor.

    - Edit the following lines (there are two of them, edit both):

    Code (Text):
    1. [rc p] = dos('startdir $documents\MATLAB' -a);
    Change to:

    Code (Text):
    1. [rc p] = dos('startdir $documents\MATLAB');
    - Save the userpath.m file.

    Problem fixed, and so simple.

    Hope this helps some who have experienced this issue.

  15. The newsgroup archive is feature of the All About Circuits Forums that searches decentralized public discussion boards and replicates the discussions locally in a forum-format.

    Although presented in a forum-format, the newsgroup archive is not open for posting questions and answers like a regular forum, instead the threads are provided as an information resource for members on a wide range of electronics topics where such information is unavailable elsewhere.

    The archive periodically updates with new items.