How to deal with "Explain/Fix this Circuit I found somewhere (and don't really understand)" kind of questions?

Question

There's a significant amount of questions¹ of the type:

Here's a {LED driver|amplifier|inverter|…} circuit I found on some website, explain how it works, or why we need {component}?

Problems with that are that

1. getting answers here (because most of us are very enthusiastic about explaining practical simple circuits) inhibits OP's own research efforts, and
2. many of these circuits are especially low-quality from an electronics point of view:
   • I've seen many circuits that are supposed to be "high-gain, low noise RF amplifiers", but are obviously copied from a website that copied them from another website, that copied them from an amateur radio mag, which copied them from another mag, which copied the circuit from someone who designed a basic Germanium semiconductor circuit without in-depth understanding of how these work in the 1950s
   • I've also seen numerous dangerous inverter circuits (things supposedly designed as resonant inverters, but where, probably through partial copy, the info on how to pick values and what not to supply with these, alongside with a total disregard for security measures), and most prominently
   • hundreds of 555-related questions that just are copies of basic 555 circuits where OP would simply need to research what the individual component values do to answer their own question (but can't, because the website they got the circuit from doesn't explain, but just display the circuit).
   • Also: the occasional total bullshack circuits sold by dubious vendors.
3. They often don't even link to the original source, which makes constructive feedback even harder.

Now, I consider these to be questions of especially low quality for the following reasons:

• they are all based on a lack of research – I know that for a beginner that is enthusiastic about building something that does something for the first time, it'll be hard to even find the appropriate ressources, but I really can't see why we're the ones to link to the same pages every day
• they might benefit future readers in the same situation, but most of them really are duplicates, and again, spotting the duplicate from a couple questions that come up in a search for the keywords in OP's question would qualify as the minimum research
• we're basically helping the proliferation and usage of badly-explained and badly-designed and outdated circuitry. I personally think we shouldn't.

So, of course, I can downvote such a question (which I think is the common thing we do for "bad question, do some research"), but I'd rather have a clear help page/rule entry that points out why exactly people shouldn't ask these.

Now: How do we want to approach such questions?

• Only downvote, close as "unclear" if appropriate?
• Only downvote, tend to close as "too broad", because an answer would basically mean explaining the basics of the type of circuit in question?
• Have a separate close reason "Don't ask questions about circuits copied from a source that doesn't explain them without in-depth understanding of the topic"?

I'm slightly leaning towards the third option, as it's the clearest.

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¹ citation might be needed, but really: I do think we agree it's a common phenomenon

Answer 1

I think we already have the tools to handle these questions. As with any broad class of questions, there is quite a range from How do I increase the gain of this amplifier:

To What's the purpose of C2 in this audio amplifier:

The first is just random garbage thrown at us, whereas the second is a legitimate question with good opportunity to teach some electronics in the answers.

The first needs to be closed for the nearest handy reason (I'd probably pick too broad, but it really doesn't matter) and downvoted because the OP clearly didn't do any research at all, and just copied some mess he found in a dark corner of the internet somewhere.

So as with all these things, the answer is it depends, and it's a judgement call each time. It's hard to come up with a clear rule, but I'll know it when I see it.

Broadly, we don't want whole circuits the OP doesn't understand dumped on us. However, explaining details of how a circuit works, what it does, why particular components were chosen, what the criteria for choosing the components are, etc, can be good questions.

Of course no matter what else, these question need to be written with a little care, no sloppiness, and the schematics must also be neat, readable, and follow common conventions.

When the first thing I see is a wiring diagram instead of a schematic, I downvote on principle, refuse to read the text, then vote to close as unclear since without reading the text I don't know what is being asked. The same holds true for anything else that makes a question annoying to read and is just wasting the time of the volunteers here.