Recent content by DaveE

I just recalled this snippet from him this morning, which I think is firmly within the PF zeitgeist. https://www.physicsforums.com/threads/how-can-i-get-admitted-into-caltech.1060447/post-7063788

Because you added a series resistance R2. Yes, I know you know that, but others may need to have it explicitly stated. This is a different network. If he didn't have R2, then it's BS. He probably ignored the initial conditions, which are pretty important for a transient response problem...

It's what's written in your local building code book(s). Sometimes it's not simple or obvious, that's why the books are big. Sorry, I don't want to read them to you, you'll just ask us more questions without actually studying the subject. I think I'm done.

This!!! RCD/GFCI should not be used as primary protection. They are an additional safety feature which simply isn't as reliable as good construction. Other code requirements are still necessary.

Also, note that isolation transformers aren't just your run of mill transformer. They will (should) have appropriate construction with either lots of spacing and insulation or grounded screens to prevent stray currents from causing excessive secondary voltage wrt earth. Some of the reasons we...

It works better if you search for knowledge, not just answers. But kudos for recognizing that you must verify the information you find on the web. Answers are more appropriate for specific, detailed, questions. General subject matter questions, like what is grounding for, how does gravity work...

Perhaps a better schematic would help:

The voltage at B wrt A is ##(V_B-V_A) \equiv V_{BA}=E_1-E_2-2IR=0## The current arrow drawn is an arbitrary polarity definition, so we'll all agree about the signs in the equation. Except your instructor, apparently.

google, dude. It works great... https://staleyelectric.com/understanding-electrical-grounding-and-how-it-works/ https://en.wikipedia.org/wiki/Ground_(electricity)

I'm no expert, but it's basically vector/matrix operations. MAC (multiply-accumulate) and inversion operations are the common benchmarks. These are crucial to solving linear algebra equations. This includes things like coordinate transformations, rotations, scaling etc. The emphasis is on...

OK, really, I'm not trolling. I'm actually curious and a bit confused about the level of interest. What's the point? Why do we need to find the wreckage? What useful information is likely to be gained? Is this like Fermat's last Theorem, just a puzzle to be solved? Or maybe something to get...

Which doesn't change my statement that metal water pipes must be grounded, accessible or not. Although nonexistence is a valid exception. Because questions like this are seldom (if ever) adequately described, I find it easier to just cite standard practice and general requirements to avoid a...

Because you are probably standing on the ground when you touch things.

In general yes. But it may depend on local codes. I really only know about California. The reason is that the utility transformer may not have a ground reference. Anytime you have an isolated source, like a transformer, you must ground the output circuit somewhere, somehow.

I hear this popular attitude a lot, but I am very skeptical. Cheap parts aren't that predictable. I think the point is that the designers aren't paying for parts that will last a really long time. They are likely choosing parts that will mostly last long enough. Also note that failures within...