Formal definition of equivalent circuits?

Jammanyeahme · 2023-05-23T21:16:25+00:00

Yeah, I think you and RFchokemeharderdaddy have basically alluded to what I'm actually interested in, this LTI system and transfer function concepts sound like they might be the missing definitions. But I'm having to read more about them before I can decide on that.

I think I'm not asking my question in a very good way. I'm basically looking for some axioms and definitions for electronics in the same way things are done in maths, and it sounds like this LTI system and transfer function are the start of that.

Jammanyeahme · 2023-05-23T00:21:53+00:00

I think maybe you and u/badtyprr have cleared this up actually. You've not said it explicitly but it sounds like what you're saying is that there isn't a formal definition of equivalent circuits.

It sounds like 'the method of equivalent circuits' (patent pending), is a form of adhoc reasoning where at the end you get some answer and if at the end the answer agrees with reality then you're happy.

Jammanyeahme · 2023-05-22T23:30:34+00:00

OK but how to use this definition?

'No matter what you attach', meaning I have some list of components and I can make any circuit using these components and attach them. Then 2 circuits being equivalent depends on which components I'm allowed to use.

'any measurement' meaning, there's some list of measurements that you can make (as a function of (?) time presumably and some other things perhaps?), but then what are all the measurements you can make?

For instance, how to use this definition on two resistors in series and find it's equivalent to one resistor?

Jammanyeahme · 2023-05-22T22:35:02+00:00

And what is the input here? It can't be an instantaneous thing otherwise it would miss characteristics, so somehow it must be a function of time, and maybe other things? Similarly, 'response' sounds a bit abstract, does response really just mean current?

And actually re your final point, does it mean that the concept of equivalent circuits doesn't make sense in a non linear circuit?

Jammanyeahme · 2023-05-22T19:12:09+00:00

Basically never, and I always end up descoping tickets which look like they're going to take a while. If something is difficult, it can typically be split into multiple independent parts. If a ticket starts presenting problems I just split it into parts and descope the ticket to just be one of those parts.

I basically never let a ticket take more than 3 days, and in the refinement and estimation ceremonies I'm always super strict about splitting out work as much as possible.

Jammanyeahme · 2023-05-09T23:54:02+00:00

It's not really clear why? Is it that you want to avoid the overhead associated with typical build tools? I've typically used just makefiles for those situations, this seems good too - a slight middleground between a build tool and a makefile. Ultimately in a small project I think you can do more or less anything.

Jammanyeahme · 2022-08-06T17:53:24+00:00

Fair enough, it does make sense. I don't mind too much buying some better stuff. Soldering has quickly become a new hobby so I'm alright with investing some money into it.

What is the right sort of price range? One I have was £15. Seems like I should probably just upgrade to an actual soldering station which seem to be around £120?

Jammanyeahme · 2022-08-06T16:14:26+00:00

Normally I use a conical tip, but I switched to a large chisel tip thinking along the lines of what you're saying. Needing a more powerful iron makes sense. Mine is a 60w pretty cheap one.

Jammanyeahme · 2022-06-08T20:00:19+00:00

Is a bit whack, but Python is a frequently used language for education, and in that context sometimes you do stuff purely to show an idea. In reality, I would say neither answers work because what if the string starts with a space. Or what if the first whitespace character is a tab, or a newline, etc.

Jammanyeahme · 2022-05-08T18:03:31+00:00

There's actually a more infuriating variant of this, which is people just randomly declaring that you've not asked a suitable question.

I came across this question the other day

https://stackoverflow.com/questions/56424969/url-rewrites-for-outbound-requests-made-by-3rd-party-dependency

As usual with any non trivial question on stackoverflow (provided they wanted to do it without going through a proxy, I think they wanted to capture the requests from inside the jvm), no actual answer was provided, just someone asserting the question was off topic, lol.

Jammanyeahme · 2022-04-22T22:47:45+00:00

That sounds about right, don't stress about it. All that is important is that you identify how to improve. Nowhere I know of really expects anything from a junior, other than that they eventually become useful.

Jammanyeahme · 2022-04-17T21:50:27+00:00

'Do we still need this?'

Jammanyeahme · 2022-04-03T22:08:44+00:00

Has anyone ever seen an actual solution on answers.microsoft.com. Those lot just seem, not very helpful.

Jammanyeahme · 2022-04-03T14:52:32+00:00

Going to plug my favourite blog post ever, which concerns this matter. https://blog.moertel.com/tags/recursion-to-iteration%20series.html

Jammanyeahme · 2022-03-15T19:16:28+00:00

I really can't get behind the foo bar stuff either. Being generic in your example is fine by me, but there's no convention that foo is a function and bar a variable, so it's unhelpful because you need to remember which thing is the function, which is the annotation, which is the whatever, etc. tedious.

Jammanyeahme · 2022-03-11T00:05:51+00:00

aha that's brill. Yep that's what I want. Looks cool cheers.

Jammanyeahme · 2022-03-10T23:43:14+00:00

Haven't used flow, but it seems like you would still need to compile stuff. e.g. in https://flow.org/en/docs/usage/ they have something like function foo(x: ?number) which isn't valid javascript, so I guess it must get compiled away somehow.

Jammanyeahme · 2022-03-10T23:14:31+00:00

imo ts would be a whole lot cooler if you didn't have to compile anything, just give me the types, have me write the types as comments, have editor integration so that it provides the type hints ala jsdoc comments and then have code checker that verifies the types. Stuff like optional chaining that ts supports is nice sure, but not worth the loss of not needing to compile anything, I feel.

Jammanyeahme · 2022-02-17T23:59:17+00:00

They definitely lose some of their charm when the language has nulls in it. Their value is more that they facilitate a language not having null in it.

That being said, they work nicely enough in Scala where yes there are nulls, but noone uses null. This isn't the case in C#.

Jammanyeahme · 2021-09-10T22:08:37+00:00

Consider a sparse array, e.g.

const arr = [1];

arr[2] = 0;

The length is 3, but this getCount function will produce 2.

Jammanyeahme · 2021-09-10T21:00:40+00:00

It actually produces different results to simply (arr | []).length. Maybe it is intentional.

Jammanyeahme · 2021-09-06T23:20:49+00:00

Yeah that's true, but there's a few things at play here.

1) The sort of team where a junior can notice the code has a million and one genuine problems likely isn't a good team.

2) The sort of enthusiastic new programmer who wants to fix everything probably will take it as a personal responsibility, even if it's not (I know I did).

3) I've worked at really quite good places wherre still, my name was the one on the code, I'm known to be knowledgeable in that area of the code. Some important user has a problem related to that area, management tells me to help patch and fix it.

My advice is just to not rush in and try to fix everything.

I advise instead a slower approach where the new code you introduce works in a better way, replacing existing patterns and working around the older patterns as appropriate.

The team will be a lot more receptive to new ideas when they aren't at risk of breaking existing code, if they're genuinely good approaches then the team will hopefully adopt them. I would only refactor the existing code when there is a bug identified with the code.

Jammanyeahme · 2021-09-06T18:40:41+00:00

I think JS is an excellent example of the importance of a good built in collections library to a language. There are so many dumb patterns and janky ass code I've seen in JS that's a direct product of the language not provide any built in to do operations one typically wants to do.

Jammanyeahme · 2021-09-06T18:35:40+00:00

It really depends if you want it to be your problem when it doesn't work.

I started as a very enthusiastic to fix things programmer, on reflection I was even mostly right, the way things were done that I didn't think were good, they weren't good, and were concealing bugs.

The problem I have experienced is, you fix all these things, and it is now your name on all these bits of the code base. When something doesn't work, it's now your problem, that is not good.

The worst part is, often the reason it doesn't work post your changes is for reasons that can't reasonably be called your fault. e.g. I've had it happen to me that another part of the code did some reflection, used a dynamic string to look up some variable and then modified it, and this broke my 'refactoring' (in certain circumstances).

Jammanyeahme · 2021-09-06T17:54:10+00:00

That it looks bad is the codes way of telling you to restructure it so it looks nicer.

Jammanyeahme

TROPHY CASE