How do I describe or draw my circuit in such a way that everybody understands what I am building? On EE.SE there is this circuit editor available to quickly draw a circuit, I'd propose to have that here too.

There are not many questions on the Arduino stack yet, but I invite everybody to add example questions that would benefit from a circuit editor in the answers below.

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    It should be allowed to use Circuit-Lab here too. – Butzke Feb 12 '14 at 11:32
  • @RobertCartaino I deliberately asked for example questions in the comments, so they can be added to the question text. The example questions are hardly worth an answer. You seem to disagree, what is your vision on this? – jippie Feb 12 '14 at 14:03
  • Comments are used to ask for clarification or suggest improvements to a post. Comments simply were not designed to be used the way you suggest. But posting 'answers' lets folks vote to gauge their usefulness. Answers allow wiki-style editing to add to and improve those answers where needed. Answers also have their own comments if users have questions or suggestions. Comments provide none of those capabilities. Comments are ephemeral by design; they may even become hidden if too many comments are added to the post. – Robert Cartaino Feb 12 '14 at 14:15
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    Another typical example of where circuit diagrams are required. arduino.stackexchange.com/questions/876/project-showcase-14 – jippie Mar 23 '14 at 7:35

11 Answers 11



We really do need Circuit-Lab on here. This is enabled on EE.SE. So as to your , could the team pretty please consider enabling Circuit-Lab on here? I would personally use this on wiring questions, or anything that needs an electrical schematic. The Stack Exchange team looks for questions/posts that would benefit by having Circut-Lab, so let's make a list of such posts/questions.

Some questions that could use this:

This is community wiki, so if you see something that would be good for this list, add it!



We really do need Circuit-Lab on here. The Arduino is more than just code. It is hardware, software, IDE and core libraries. This SE needs efficient/effective methods to communicate all of these functions of the Arduino eco's or framework.

Note SO's arduino tab has many questions with long winded descriptions of circuits, that work in conjunction with code. Where it would be best described with a schematic from Circuit-Lab. A picture is really worth a thousand words.

Often with these cases. The comments explode and drag out with simple questions about what was omitted in the written description. Causing the question to be answered in the comments and not with a clear answer, if at all. In these cases a schematic would provide better questions and result in better answers.

As the answers should also allow Circuit-Lab too.

  • I can't help but notice that you copied exactly the first two sentences of hichris123's answer. – The Guy with The Hat Feb 14 '14 at 15:40
  • It was well put. Where I believe I immediately went into additional value added content. – mpflaga Feb 14 '14 at 15:46

Another question that benefits from a decent circuit editor: How to switch an external circuit with Arduino?

This is typically what happens when none is available. Now I have to grab pen and paper and follow the description word for word while drawing what I think the author meant. Someone else may draw another circuit. And the people who answer, need to make descriptive text too so the OP can grab a piece of paper in turn to try understand what the answerer tried to capture in words.


Fritzing appears to be the official standard for Arduino circuits. (Site currently mostly down at the moment.)

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    Beware that the Fritzing wiring diagrams are not really useful for sharing the circuit diagram, they are useful for reproduction of the circuit. You need datasheets for all components handy to interpret how it is connected and the result will be hard to follow. I saw Fritzing also allows for circuit diagrams, but I don't know how well that integrates with the site. – jippie Feb 12 '14 at 14:00
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    I would think cross compatibility between EE.SE's C-L would be beneficial. – mpflaga Feb 14 '14 at 15:27
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    @jippie - You know that EE.SE has a (kind of) standard of asking posters to include proper schematics (with component descriptors and all). That's great and I think we should have the same here, but I honestly thought that Fritzing diagrams could be ok, too, just so we make the transition easier for the less experienced. Arduino sites use it for a reason. What do you all think? – Ricardo Feb 15 '14 at 1:12
  • @Ricardo it is not just the asking posters that may want to include a quick diagram. Anyways, I'm not trying to say one is better than the other, my point is that it would really help to have an easy way to include circuit diagrams in questions and answers. – jippie Feb 15 '14 at 7:06
  • One thing to add: Fritzing screenshot could be useful. No need to do a full schematic for a simple LED demonstration (say "Do I really need a resistor?") to add color, but then for more advanced projects request that the OP draws a schematic using Circuit-Lab or using the "schematic" tab on Fritzing and taking a screenshot there. Screenshots are the only option until the dev team implements anything: that is if they do ever. – Anonymous Penguin Feb 17 '14 at 14:13

Another typical example of where circuit diagrams are required. Project Showcase '14

Every answer with that should probably ultimately contain a circuit diagram.



simulate this circuit – Schematic created using CircuitLab

While I generally agree with Pops, I looked at some of the other sites with this setting enabled:

It seems to me that the list fits into what you might call hobbyist electronics/embedded systems sites. So I'm a little more convinced the feature will be used for good and not ill.


Adding my vote for a schematic editor. The best way I have at the moment (even though I have Fritzing) is a pen, paper, and camera, as in this answer.

  • Poor mans Electronics CAD kit :) – Paul Dec 1 '16 at 16:48
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    Man's poor CAD, for sure. – JRobert Dec 2 '16 at 11:57
  • That's more of a political correct naming ;D – Paul Dec 2 '16 at 14:19

Try to use schem-it for online or you could try using an offline circuit simulator just like multisim and circuit wizard.@


Shown below is a simple schematic created with CircuitLab, which is a drawing and simulation package referred to in a number of answers above. It appears that CircuitLab recently (October 2016) became available in arduino.stackexchange.

To use it, click on the circuit icon next to the image icon in the editing tools bar (at top of edit box).

When you edit a question or answer containing a CircuitLab schematic, the schematic can be edited also. The editor's components list contains numerous passive components, some generic transistors and op amps, and a few ICs (eg NE555). Apparently, to draw an Arduino is a fairly lengthy process starting with a Custom box (from the Annotation section). However, if one does get drawn and saved, it can be reused. From the FAQ: “How can I save my custom part settings for re-use on another schematic? ... you can copy and paste an item from one browser window to another and ... all of its parameters will be copied and pasted...”

CircuitLab documentation is available at circuitlab.com. Note, the CircuitLab editor and simulator does not work in all browsers; see CircuitLab Documentation: System Requirements for more information. Briefly: “CircuitLab officially supports Google Chrome and Mozilla Firefox”. While Apple Safari and Opera are not officially supported, users report success.


simulate this circuit – Schematic created using CircuitLab

Note, answers to “Embedding a schematic editor” on electronics.stackexchange meta include comments similar to above; replies from CircuitLab developers; and a couple of alternatives that now are moot. Several non-embedded schematics programs are listed in “Suggestions for a program for drawing simple schematics”.


This is a somewhat difficult spot. For a site like Mathematics SE, it's a no-brainer that MathJax support should be enabled, because nearly all posts use and benefit from it. Similarly, we'd never consider adding a chess game replayer to Ask Ubuntu; it just doesn't make sense.

Here, the distinction isn't so clear. It's obvious how circuit diagrams are related to the topic of Arduino, but the list of posts that could benefit is pretty short as-is. And adding a package, even one that we already use on another site, isn't free; for example, see Nick Craver's (somewhat technical) explanation of testing MathJax on Stack Overflow. Granted, those are different dependencies on a different site, but the principle is the same.

The point of all this is, I haven't seen enough of a need for this tool demonstrated to justify enabling it. I realize the list is a bit old, and was probably forgotten about for a while, so I'm not formally declining the request just yet. If you're still interested in having a circuit diagrammer on Arduino, show me that it will benefit more than just a handful of posts!

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    I don't see how MathJax is a no brainer for Mathmathics, but a decent circuit editor isn't to Arduino. The list of posts that benefit is far from complete. I think there would've been a lot more quality answers on this stack if those tools would've been available. A lot knowledgeable people are dismissed because of the lack of basic tools required for them to share their knowledge. Anyways I left this stack ages ago, I don't mind. – jippie Jan 28 '16 at 19:48
  • Because many questions here (based on a quick, non-scientific sampling) seemed to be purely about code or other issues that don't involve circuit design/layout at all when I was writing the answer. I might be sympathetic to arguments like "more questions would have included diagrams had the tool been available, and it was too much of a pain to include them any other way" but nobody's made such an argument or shown any evidence of that. – Pops Jan 28 '16 at 20:28
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    Hardware information isn't optional for embedded systems. Without hardware information, many questions are left unanswerable. The four posts in [list of posts that could benefit ](meta.arduino.SE/a/38) show various uneven ways that more experienced users have worked around the lack of schematic capture (and all four of those questions successfully got answered). That's not a list of unanswered questions that needed hardware information to become answerable. Wish I could come up with a good SEDE query for this... – MarkU Jan 30 '16 at 9:35
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    Unlike electronics.SE where about half of new questions are from experienced users, most Arduino.SE new questions are from "rep 1" users who mostly lack technical electronics background. On electronics.SE, new users are commonly prompted to "use CTRL+M to insert your schematic", but on Arduino.SE we're lucky if we eventually get a blurry cellphone photo of a breadboard, or a crummy fritzing build diagram. In some cases there's a reference to a specific "shield" make/model, and the hardware info must be searched offsite. This leads directly to poor quality questions... – MarkU Jan 30 '16 at 9:35
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    Tag arduino is the single most popular tag on electronics.SE, but that community doesn't generally have the patience to interface with less experienced Arduino users or deal with the various quirks of the Arduino toolchain. Low quality Arduino questions frequently get migrated (dumped) into Arduino.SE, where the very tool needed to improve question quality is missing. Here there's a very small cadre of experienced users answering a wide range of posts from new users, and the lack of schematic editor hobbles the core users -- so the site struggles to graduate. – MarkU Jan 30 '16 at 9:36

I believe if we have a way to embed live circuits than we might have a better tool to explain things... It's not just a matter od schematics, but showing people the current flow usually maked their life a lot easier.

My votes goes to http://www.falstad.com/circuit, but I would love to see embeddable links

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