Quick links to: Icons Used  Compatibility  Contributions  Disclaimer  Email  FAQ 

About this Site:
Circuit Exchange International (CXI) is my personal, non-profit home page. First created back in March 1999 and intended for electronics hobbyists, engineers and enthusiasts everywhere. Currently there are 310 schematics divided into 11 categories. Also included are tutorials, design and simulation sections. If you ever type Circuit Exchange International, then you'll realise why I abbreviate it to CXI.

This site has been viewed from over 220 Countries in all 6 Continents. Although largely a single effort, I do welcome contributions to this site. This website is made entirely on Linux using Bluefish All graphics are produced with the Gimp.


Icons Used
Some pages contain icons, these are explained here. Any page with the "Colour" logo (shown left), is where an older black and white page has been converted to colour. You can also visit the update page to see a list of new or modified pages. The link symbol, represents an external link. If the normal cursor, changes to a hand, this indicates a clickable link, or other action such as zoom or scroll will take place. Some links are underlined, but others may not be, this rule also applies to any web page on the internet.
Icon for the Circuit Index
Article Index.
Analysis Section
Design section
Theory section
Circuit Exchange Gallery.
All flag icons are links to the contributors page.
The page contains a Fritzing breadboard layout.
Contains assembly code.
Contains hex code.
Document in Adobe format.
takes you to the contributors page. The icons used are for the Linux Desktop KDE4, some with slight variations. All future icons will be included on this page.

I have a new newsletter hosted by Freelists.org I use this to email site changes and updates. Just click the link below, or fromCircuit Exchange Newsletter the index page and enter your email address.

Circuit Exchange Newsletter

You will then receive email when my site is updated. After entering your email address and clicking send you will receive an email message (Click here for sample). You must then click the link to confirm highlighted in red, after which a second email will arrive with the word subscribed (sample here). You may delete these two emails if you want. Any other emails on the newsletter will be about new circuits and articles. The old service on Domeus recently closed. My apologies for any inconvenience.

The web has become an "Internet of Things" (IoT), and many of you reading this, may be viewing on tablets, mobile phones, or even Smart TV's. When I first created Circuit Exchange, I only had to create content for PC's and laptops. Now with various devices and different display resolutions, it is a much more difficult job to create a consistent look.

People like interactive sites and animated graphics, and using HTML5, CSS3 and jQuery my site is undergoing continuous changes. Whilst most internet browsers adhere to the rules laid down by the W3C, some do not, most notably early versions of Microsoft's Internet Explorer. IE10 and higher now follow the standards of other browsers, but if something does not look correct, and you use Windows, you can always try Google Chrome or Firefox. (The circuit pages should always be view-able though.)

This site is also Android friendly and will work with most tablets. I currently test with an Android Tablet, Samsung Smart TV @ full 1080p resolution and a PC monitor at 1280x1024. Some pages may be a little hard to see on smaller displays, so I recommend a minimum resolution of 1024x768 pixels.

Email Address:
To combat spam the email address below is an image, not text. You need to enter the address directly, it is not a link.

For verification the image reads: hal eight zero zero zero b at yahoo dot com.


You are welcome to contribute circuits or articles. Diagrams are best preserved in either .png or .gif format, images in .jpg format. I can accept most document formats, but its probably best to send in either .doc or .odt Libre Office or (Open Office) format. I can accept schematics from LTspice, Eagle, Kicad or Ktechlab direct.

The home page is translated into 10 languages and I am most grateful to the following people who have made this possible :-
Amanda Van Leeuwen, Ricardo Venegas, Sindhu Adi Wijaya, Paulo Roberto do Amaral, Maria Rosendahl, Marco Deferre, Fidel from Ukraine, and Hartmut Schneider. All contributors appear on my credits page link below. You can also see my viewers gallery and disclaimer. I am also very grateful to Ron J, whose work appears prominently in the Alarm Circuits. Ron has also kindly made his meticulous artwork available to use.

Because of extended contributions and support the people named below have full permission to use or reproduce any article, circuit or content from Circuit Exchange International:

Ron J  Ramon Vargas  Graham Maynard  Thomas Scarborough  John Samin

Contributors Page

Gallery Page


Information on this web site is provided "AS IS" and without warranty of any kind. Under no circumstances shall the author or any contributor, be held liable to any person, company, or third party for any claim for damage, lost profits or business interruption, lost email, invalidity of warranties or guarantees, loss of service or data on any computer or network, resulting from direct or indirect use of this web site, even if advised of the possibility of such damages. The information on this site may contain errors or bugs or other limitations. The owner of this site assumes no liability or responsibility for any errors or omissions on this site and shall not be held liable to any person, company or third party for civil liabilities, summons or court orders resulting from direct or indirect use of this web site.

Please Note:
1. This site may contain technical inaccuracies or other errors.
2. Please DO NOT copy from this site. If you would like to use circuits please email me.
3. Linking to this site is actively encouraged, but please create a working link back to Circuit Exchange International
5. You may link to this site or any page, but please make a reference to the original contributor.
6. Some sites have taken circuits from this site and claimed it as their own work. They are without honour.

Privacy Policy (Cookies)
This web site is free from commercial advertising and is totally free. The only cookies used on this site are for the web counter, domeus newsletter and stat-counter. Information collected by the web counters includes your ISP (internet service provider), country code, operating system, browser, date and time, and pages visited, and referral link. Google widgets is used for translation and search site. No information is sold or passed on and counters serve to indicate popularity of pages.

Frequently Asked Questions
i) Most components are labeled using the System International numbering system.
ii) Please don't ask for schematics for domestic electrical or electronic equipment, I don't have any.
iii) This site is non-commercial, I do not sell or buy, components or circuits on this site.
iv) The update page contains links to the newest pages on my site.
v) I regret that I cannot help with college/school/university/project work, but see links below.

Help on the Internet
Sorry but I cannot help with college or course work. However, before asking for help, try to solve your problem yourself or search on google. Remember that anyone who helps is a volunteer and gives their time freely, demanding that you need an answer by a specific date will not help your plea. If you are still stuck try the following forums:

Electrical Engineering Community This site has discussion forums and a great source of information.
Electronics Point

About the Web Master
My interest in electronics started with radio. Tuning my parents old radiogram, I was fascinated by the multitude of radio stations that could be heard. It wasn't long before I made a crystal radio, though only having a small garden meant that my longwire aerial was small and only a few stations were heard. I did try a more complicated radio though never got it to work. One year I also got a 65 in 1 Electronic Lab. These can still be bought on Ebay and are a great introduction to electronics. Working through the manual I learnt a lot and then started making my own circuits. On the Workbench

As a hobby, electronics can be rewarding, sometimes challenging. It is always good to hear from fellow hobbyists around the world. Some recommended books, "The Art of Electronics" by Harrowitz and Hill, and if you are interested in circuit simulation, "The Spice Book" by Andrei Vladimerescu is a great technical reference. These may be available in a library near you.

Currently "on my workbench", shown right I have a motor control and torque circuit, and a Raspberry Pi Analog Interface. These circuits will be published shortly.

Registered Linux User 189959
Last update Tuesday 2ndDecember 2015