Electronics circuit designed by Tomi Engdahl

Nothing on these pages is for sale, and I will not build these or sell kits or parts to you.

I have designed those circuits for my own hobby use and are presented here as is. I have tested the circuits presented in this page but there is no guarantee that the circuit descriptions and diagrams are entirely correct. I will try to correct all the error in the circuit diagrams when I or somebody else find those.

Please note that I do not supply electronic components or kits for building any of the projects featured. I do not have list which would be the best source to get the needed components in various countries. I strongly advise readers to check that all parts are available before commencing any project.


These pages are not an advertisement for a commercial product. I don't have components, circuit boards or kits for sale for those projects (if someone has interrest in turning some of those circuits to kits and sell then contact me for more deltails). The circuits are mostly build on some quite small set of basic electronics components which I basically use when I need to build something which does not need any very special components. I will try to answer your questions if they are relevant but I don't have too much free time nowadays.


This information and the circuits are provided as is without any express or implied warranties. While every effort has been taken to ensure the accuracy of the information contained in this text, the authors/maintainers/contributors assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.

I disclaim everything. The contents of the articles below might be totally inaccurate, inappropriate, or misguided. There is no guarantee as to the suitability of said circuits and information for any purpose whatsoever other than as a self-training aid. I.E. If it blows your equipments, trashes your hard disc, wipes your backup, burns your building down or just plain don't work, IT ISN'T MY FAULT. In the event of judicial ruling to the contrary, any liability shall be limited to the sum charged on you by us for the aforementioned document or nothing, whichever is the lower.

I will not be held responsible for any damages or costs which might occur as a result of my advice or designs. Not any of my designs are allowed to be used for commercial purposes without my written authorization .

Audio circuits

Video circuits

Computer circuits

Data communication circuits

Light effects and controllers

Telephone circuits

Power supplies

Measuring equipments

Other circuits

Information on getting the components

The circuits above are mainly designed using components which are easily available types in Europe. When I start to design circuits I usually pic the components from my basic electronics components list.

If you have problems on finding components to the electronics project on this document collection then don't e-mail me how to find those components. I know where to buy the components in Helsinki in Finland. If you happen to live in some other country or city then I don't know what are good places for you toget those components. Please consult my list of electronics component dealers to find one which can supply you the components.

If you happen to live in USA, you can't easlity get exactly the same components, but you can find suitable replacements for most of the components from Radio Shack using my European component types to Radio Shack types table. If you have problems in reading the component value markings then read the component markings description document.

Electronics documents written by Tomi Engdahl

FAQs I have written

Tomi Engdahl <[email protected]>