EEVblab #2 - Are Electronics Hobbyists Useless?

[rs20]

proof that math can prove anything. which is why i stay away from it ...  the circuit on the bench does not lie. no matter what the maths say.

Correction: proof that fallacious proofs can prove anything. Which is why I stay away from fallacious proofs, by understanding and rigorously applying maths.

[jaxbird]

proof that math can prove anything. which is why i stay away from it ...  the circuit on the bench does not lie. no matter what the maths say.

That is a ridiculous statement from an otherwise intelligent person. Surely using literally measuring sticks is not what got us to the Moon, Mars and beyond. Math and our basic, but evolving, understanding of the laws of the universe are the primary tools to bring us forwards as a species. Not trial and error using crude lengths of strings, sticks and stones, we left those behind thousands of years ago.

[Simon]

Maths is the underlying system that keeps everything working and explains how it works. The problem is that often the way to go about solving an equation can be a little elusive as plenty of options look like the correct one but bring about totally the wrong result and hence it is easy to prove anything with maths if you go about it the wrong way. If you are using these mistaken methods to demonstrate a so-called truth to somebody who is not very well up on maths I could be one of those, you would easily demonstrate something which is completely untrue. A proper understanding of maths will see you through.

The problem we have with today's society is that people think that just because they can use a smart phone and that a smart phone exists they are as great as the guy who made it and they don't need to know anything else. Fact is that in this society where most people do not have to work out very much for themselves because of the technology we have people are becoming more ignorant again as they are given tools they do not understand the workings of but they can used to produce a result. Therefore they do not understand their own lack of skill or care because what most people care about is the result not their skills. This is why rigourous qualifications are important and not some of the mamby pamby shit that is handed out by privatised education companies like ICS learn.

[idpromnut]

I was always under the impression that engineering was an practical domain. You can create delightful constructs using mathematics that may be impossible to actually build (for the moment). I think that is the reason to appreciate math, use it as the tool it is, but not to rely on it solely. Like all models, the practical usefulness of an equation is only as good as our ability to validate it against the real world.

[Simon]

And until you get into stupidly complex maths most of it is very relevant and needed. I have found that I have hit the limit point where I can rely on rules of thumb and I am now having to study a lots of maths that I should have already learned many years ago in order to learn all of the theory of electronics that I would like to know. Understanding a circuit topology includes understanding the maths that explains how the components interact. For example a switch mode power supply, you can build one with rules of thumb you can get controller chips off the shelf and follow the form and has already worked out for you, or you can have a thorough understanding of how each component in the circuit works and be capable of designing your own from scratch but you won't do that without maths.

For most practical applications off-the-shelf switch mode power supply chips are just fine and so we can all get by by simply following the formula given on the datasheet which are a derivative of more complicated calculations that are simplified for the end user under certain circumstances. But as soon as you will need to design yourself something a bit peculiar and bespoke you will then find you are totally on your own and you will probably need a decent level of maths to work out your circuit.

[tggzzz]

As someone once said, the best maths is the maths you can use without reverting to deriving everything from first principles. But you need to understand the first principles so you don't violate them.

Example -1=1, without misuse of zeros, and in an example which can foul up frequency domain analysis of electronic circuits:
1: sqrt(-1) = sqrt(-1)
2: therefore sqrt(-1/1) = sqrt(1/-1)
3: therefore sqrt(-1)/sqrt(1) = sqrt(1)/sqrt(-1)
4: therefore sqrt(-1)*sqrt(-1) = sqrt(1)*sqrt(1)
5: therefore -1 = 1
QED

Almost everybody can correctly determine that the error is going from 2 to 3, but they can't say what the error is. I've only come across one person who could give the reason.

Back before Christsmas I had PMs requesting that I show the error. Given the difficulty of formatting maths on this forum, it will be difficult, but I'll do my best.

Firstly, as any fule knos, "i" represents current, so I'll use the traditional "j" to be sqrt(-1), and I'll use "w" instead of omega=2*pi*f. Secondly, this kind of manipulation can arise when doing frequency domain analysis of circuits, where term such as ¹/_(R+jwL) are common. Thirdly, I'll note that MrFlibble's comment about using the Euler form is equivalent to using the complex conjugate described below.

The key is recognising that a full representation of a complex number is a+jb, and that sqrt(-1) is a special case when a=0 and b=1.

If we want to "get rid of the complex denominator" / "move the j to the top line" in ¹/_(a+jb) we have to multiply top and bottom by the complex conjugate (a-jb).
(¹/_(a+jb))*(^(a-jb)/_(a-jb))

Multiplying out the numerator and denominator gives
^(a-jb)/_{(a²-jab+jab+b²)}
or
^(a-jb)/_(a²+b²)

Now for the special case where a=0 and b=1, we can see that ¹/_j = ^-j/₁ , and that's why
sqrt(1/-1) != sqrt(1)/sqrt(-1)

And that's why despite "the best maths being the maths you can use without reverting to deriving everything from first principles", you need to understand the first principles so you don't violate them.

I hope that's all legible

[jpb]

As someone once said, the best maths is the maths you can use without reverting to deriving everything from first principles. But you need to understand the first principles so you don't violate them.

Example -1=1, without misuse of zeros, and in an example which can foul up frequency domain analysis of electronic circuits:
1: sqrt(-1) = sqrt(-1)
2: therefore sqrt(-1/1) = sqrt(1/-1)
3: therefore sqrt(-1)/sqrt(1) = sqrt(1)/sqrt(-1)
4: therefore sqrt(-1)*sqrt(-1) = sqrt(1)*sqrt(1)
5: therefore -1 = 1
QED

Almost everybody can correctly determine that the error is going from 2 to 3, but they can't say what the error is. I've only come across one person who could give the reason.

Back before Christsmas I had PMs requesting that I show the error. Given the difficulty of formatting maths on this forum, it will be difficult, but I'll do my best.

Firstly, as any fule knos, "i" represents current, so I'll use the traditional "j" to be sqrt(-1), and I'll use "w" instead of omega=2*pi*f. Secondly, this kind of manipulation can arise when doing frequency domain analysis of circuits, where term such as ¹/_(R+jwL) are common. Thirdly, I'll note that MrFlibble's comment about using the Euler form is equivalent to using the complex conjugate described below.

The key is recognising that a full representation of a complex number is a+jb, and that sqrt(-1) is a special case when a=0 and b=1.

If we want to "get rid of the complex denominator" / "move the j to the top line" in ¹/_(a+jb) we have to multiply top and bottom by the complex conjugate (a-jb).
(¹/_(a+jb))*(^(a-jb)/_(a-jb))

Multiplying out the numerator and denominator gives
^(a-jb)/_{(a²-jab+jab+b²)}
or
^(a-jb)/_(a²+b²)

Now for the special case where a=0 and b=1, we can see that ¹/_j = ^-j/₁ , and that's why
sqrt(1/-1) != sqrt(1)/sqrt(-1)

And that's why despite "the best maths being the maths you can use without reverting to deriving everything from first principles", you need to understand the first principles so you don't violate them.

I hope that's all legible

You don't need to resort to anything so extensive. The simple fact is that the sqrt(1) is +/-1 so you could just put
sqrt(1) = sqrt(1)
therefore -1 = +1 as they are both the sqrt(1). Of course the convention is to take the positive root but the problem illustrates what goes wrong if you misapply this.
You're essentially finding the root(s) of the quadratic x^2-1=0 and there are two roots and similarly for x^2+1=0. Doing this twice and choosing different roots each time is bound to lead to inconsistencies.

[Simon]

The misuse of math or other very factual system has long been misused to "prove" various scams 

[tggzzz]

As someone once said, the best maths is the maths you can use without reverting to deriving everything from first principles. But you need to understand the first principles so you don't violate them.

Example -1=1, without misuse of zeros, and in an example which can foul up frequency domain analysis of electronic circuits:
1: sqrt(-1) = sqrt(-1)
2: therefore sqrt(-1/1) = sqrt(1/-1)
3: therefore sqrt(-1)/sqrt(1) = sqrt(1)/sqrt(-1)
4: therefore sqrt(-1)*sqrt(-1) = sqrt(1)*sqrt(1)
5: therefore -1 = 1
QED

Almost everybody can correctly determine that the error is going from 2 to 3, but they can't say what the error is. I've only come across one person who could give the reason.

Back before Christsmas I had PMs requesting that I show the error. Given the difficulty of formatting maths on this forum, it will be difficult, but I'll do my best.

Firstly, as any fule knos, "i" represents current, so I'll use the traditional "j" to be sqrt(-1), and I'll use "w" instead of omega=2*pi*f. Secondly, this kind of manipulation can arise when doing frequency domain analysis of circuits, where term such as ¹/_(R+jwL) are common. Thirdly, I'll note that MrFlibble's comment about using the Euler form is equivalent to using the complex conjugate described below.

The key is recognising that a full representation of a complex number is a+jb, and that sqrt(-1) is a special case when a=0 and b=1.

If we want to "get rid of the complex denominator" / "move the j to the top line" in ¹/_(a+jb) we have to multiply top and bottom by the complex conjugate (a-jb).
(¹/_(a+jb))*(^(a-jb)/_(a-jb))

Multiplying out the numerator and denominator gives
^(a-jb)/_{(a²-jab+jab+b²)}
or
^(a-jb)/_(a²+b²)

Now for the special case where a=0 and b=1, we can see that ¹/_j = ^-j/₁ , and that's why
sqrt(1/-1) != sqrt(1)/sqrt(-1)

And that's why despite "the best maths being the maths you can use without reverting to deriving everything from first principles", you need to understand the first principles so you don't violate them.

I hope that's all legible

You don't need to resort to anything so extensive. The simple fact is that the sqrt(1) is +/-1 so you could just put
sqrt(1) = sqrt(1)
therefore -1 = +1 as they are both the sqrt(1).

No.

While true, that neither explains the problem/solution nor illuminates the way in which it bites in s-plane (frequency domain) analysis. I refer you to my hint concerning ¹/_(R+jwL) for an example of the latter.

[tggzzz]

The misuse of math or other very factual system has long been misused to "prove" various scams 

The issue of scams is a red herring.

The fallacious maths I have indicated occurs accidentally without malevolent intent, in real-life engineering situations. Root cause: carelessness and/or not understanding the fundamentals.

[Richard Crowley]

The misuse of math or other very factual system has long been misused to "prove" various scams 

You mean like the "30 second recharging Rechargeable Battery"?   

[jpb]

No.

While true, that neither explains the problem/solution nor illuminates the way in which it bites in s-plane (frequency domain) analysis. I refer you to my hint concerning ¹/_(R+jwL) for an example of the latter.

It still seems to me to be a case of carelessness when taking roots, particularly of complex numbers.
A similar case would be:
(-1)*(-1) = 1
sqrt((-1)*(-1)) = sqrt(1)
sqrt(-1)*sqrt(-1) = sqrt(1)
j*j = 1
-1 = 1

Perhaps I've never come across it as a real problem because in most analysis you tend to only take square roots of real results such as the modulus squared of the complex result to get the magnitude. I'm not sure under what circumstances it is necessary to take complex roots in circuit analysis. Such a + b(jw) analysis is  generally used in linear analysis of circuits and having a root function would be nonlinear.

[tggzzz]

I'm not sure under what circumstances it is necessary to take complex roots in circuit analysis. Such a + b(jw) analysis is  generally used in linear analysis of circuits and having a root function would be nonlinear.

No, it isn't necessary.

In circuit analysis such errors can occur during simple rearrangement of terms in linear equations.

[bbogita]

In my own case.  I was an EE student but switched to CompSci my SENIOR year.   It was the mid 80's and I simply decided that I liked all the new exciting computer stuff more.  I don't regret that decision, the 80s, 90s, and first decade of the 2000's were exciting times in IT and provided a very interesting career.

So, while I am not an EE, I ended up an IT professional for the last 20 years, but it was my original interest, and it and ham radio have made it my hobby.  I don't remember everything from school, and lots of it is not all that up to day anyway probably, but it certainly provided a very good 'base' for my hobby electronics experimentation.  In my hobby level electronics I am pretty sure I would fit your skills myself and I have never worked a single day as an EE or with electronics professionally, its all been an IT career for me.

For many people computer stuff is a hobby, for me at the skill level I have now, its almost too easy to do nearly anything IT related and it has become just a "job" that I don't want to do at home as well as work.  So ham radio and electronics provide that same mental stimulation and challenge that computers used to provide me when I was young.

I do believe your best bet to find someone that would fit WOULD be either a hobbyist or maybe a retired EE who used to be technical but at some point got into mgmt, sales, consulting etc, but still has a love of electronics and would enjoy doing it again.

Frankly, I think you should have "Advanced Amateur Radio License" as a job requirement.

If you want a group of non-EE professionals who have serious electronics skills, hang around ham radio people.

Haha, I smiled when I read this I applied for the job and I have been slightly worried about my qualifications. (I think I have them, but then ofc everyone thinks they have everything) Now I feel much better knowing people value ham licensees. BTW, if you ever feel like talking some time (I assume you're a ham) I'm KM4GPL and the 2m band rocks

[Alexei.Polkhanov]

I think North American education dramatically misses out somewhere on teaching math to kids when they are young or something. I found that number of people (engineers, programmers, accountants) that are scared of math among North Americans are drastically higher than let's say among Indians, Chinese or those who get Soviet education or those who went to school in  Europe. I must say they usually catch up when they go to university but they go through so much pain and fear never goes away. It is like they had this drastic experience of drowning in backyard pool when they were kids and even though they can swim now fear is always with them.

Going back to reality vs mathematical abstraction - there is famous quote of Richard Freymann: 

"physics is to mathematics as sex is to masturbation"

[AlfBaz]

Now for the special case where a=0 and b=1, we can see that ¹/_j = ^-j/₁ , and that's why
sqrt(1/-1) != sqrt(1)/sqrt(-1)

I don't get it, namely because I'm a hobbyist
Isn't

The same as

Which seems to be a standard convention as shown in this snippet here from Wikipedia on complex impedance and also in various text books

[Rory]

I think North American education dramatically misses out somewhere on teaching math to kids when they are young or something. I found that number of people (engineers, programmers, accountants) that are scared of math among North Americans are drastically higher than let's say among Indians, Chinese or those who get Soviet education or those who went to school in  Europe. I must say they usually catch up when they go to university but they go through so much pain and fear never goes away. It is like they had this drastic experience of drowning in backyard pool when they were kids and even though they can swim now fear is always with them.

Going back to reality vs mathematical abstraction - there is famous quote of Richard Freymann: 

"physics is to mathematics as sex is to masturbation"

There has been a shift in priorities over the past 40 years away from numeracy and literacy (the 3 R's) and toward teamwork, "problem solving" and interpersonal skills as desired by employers.

In other words, they don't care if Jack can't add or subtract, read or write (since that can be done with hardware these days...) but must play well with others, do as he is told and follow the leader.

Interesting article here:
http://devlinsangle.blogspot.com/2015/01/your-fathers-mathematics-teaching-no.html

[Simon]

I think North American education dramatically misses out somewhere on teaching math to kids when they are young or something. I found that number of people (engineers, programmers, accountants) that are scared of math among North Americans are drastically higher than let's say among Indians, Chinese or those who get Soviet education or those who went to school in  Europe. I must say they usually catch up when they go to university but they go through so much pain and fear never goes away. It is like they had this drastic experience of drowning in backyard pool when they were kids and even though they can swim now fear is always with them.

Going back to reality vs mathematical abstraction - there is famous quote of Richard Freymann: 

"physics is to mathematics as sex is to masturbation"

There has been a shift in priorities over the past 40 years away from numeracy and literacy (the 3 R's) and toward teamwork, "problem solving" and interpersonal skills as desired by employers.

In other words, they don't care if Jack can't add or subtract, read or write (since that can be done with hardware these days...) but must play well with others, do as he is told and follow the leader.

Interesting article here:
http://devlinsangle.blogspot.com/2015/01/your-fathers-mathematics-teaching-no.html

The bottom line is that the so-called developed world brings its children up to be lazy. Asian children are probably being taught harder subjects at a younger age because they live in a competitive society that knows that it has to compete with the rest of the world so they do just that whilst America and Europe sits on their laurels and think they are perfect.

Every time I see a schoolkid walking down the road I have to cringe. Why do we need to dress our schoolchildren in the UK up like future office workers. What is the matter with proper jobs? As soon as somebody gets a desk they think they are better than other people. In the UK we keep watering down our education standards to make it look like the children we are telling to take it easy can look better and better. Fact is any child brought up in Asia could probably knock the socks off of any UK child in adult life. Yes we have these buzzwords these days like teamwork, networking and interpersonal skills. These are all things which children would learn through play, oh yes of course they don't play any more they spend all day in front of a television or a videogame or bloddy Facebook! Because nobody likes to interact and now we have to teach children how to interact rather than maths apparently. The first step to being a good team player is knowing what you are damn well doing. You can have the greatest interpersonal skills on earth if you cannot do the job you are paid to do you are a pointless piece of shit. I sit opposite a guy at work who can talk for hours and get on great with anybody but when it comes to doing work or developing a new idea he's a hapless useless idiot.

Everybody these days wants to get into sales because it easy doesn't really require any work just to gift of the gab. It is time we stopped putting our children and in fact anybody on a pedestal. Life is tough get on with it or get out particularly if you want to take on fields like engineering. After all there are always jobs the people who don't want to learn the skills we need and those jobs are as important as those of engineers as well.

[SeanB]

Simon, you should see the SA education system. At best they are proud that they are going back to making the pass level 50%, as opposed to the one for the last few years of 30% being a pass, or you just get bumped up if you are not even at that level. Not helped by an education department that cannot even provide little things like schoolbooks, teachers, schools............. But they do have a nice fancy new central office suite for the top levels, and all are driving department supplied luxury 4x4 vehicles.

[Simon]

Simon, you should see the SA education system. At best they are proud that they are going back to making the pass level 50%, as opposed to the one for the last few years of 30% being a pass, or you just get bumped up if you are not even at that level. Not helped by an education department that cannot even provide little things like schoolbooks, teachers, schools............. But they do have a nice fancy new central office suite for the top levels, and all are driving department supplied luxury 4x4 vehicles.

The problem with teachers in the UK is that they never actually left school and have never seen the real world I had to work in it and have no idea, I actually make a point of not bothering to pursue teachers on dating websites if they have down that they are a teacher I just pass over the profile. It is because of failed education systems which are run by politicians who want to outdo each other on how many children pass without upsetting the children that is why I have no faith in a school system and value much more people who learn because they have a passion for the subject and do it as a hobby. When schools and universities function as independent companies that need to be profitable how the hell can we have a proper education system when schools and universities will be competing to get students in so that they can stay afloat financially so the most successful education institution is the one that passes the most students. This is not a recipe for good qualifications. Education is supposed to be an investment not a profit making business. That is why we all pay into the education system because if we were to have a country full of educated and clever people we would have a thriving economy and a better chance of not being misled by our politicians. For the political class it is convenient that people are lazy and easily pleased with a qualification they have not earned because it means they have not been taught to evaluate things properly and will be easily blinded by said politicians.

[DIPLover]

Somehow this situation reminded me of the BOFH (Bastard Operator From Hell) episodes from way back when, and mostly of his "faithful" assistant, the PFY (Pimple Faced Youth).

I hope you can find a real, smelly, basement-dwelling, socially awkward, unsung genius and fashion him into the next electronics SuperHero.

That would be awesome.

[yym]

Dave, your expectation are way to high!

It is not that skilled hobbysts/engineers don't exist, they do, but they would never apply to your job offer.
You are basically offering a dead end job which doesn't pay much, and part of your job is to take out the rubbish.
(ok i get it that it is a joke, but still...)

In this field you can easily find a job, fresh students who barely have any skills are hired by the dozens (with good pay).
If you have half the skills you mentioned in your offer, you are hired on the spot.

Why would someone work for you when they can work in big companies, where they have a future, they offer internships, on the job trainings,
you can work with latest technologies, million dollar equipments etc, you can build your carrier there.

[yym]

A class diagram allows you to deconstruct the problem domain, see the connections, understand what is what. I've seen too much software that was written without the creator taking the time to understand all that.

IMNSHO experience, a class diagram is one of the least informative diagrams.

What is far more useful are:

• state diagrams, i.e. the Harel StateCharts. No, Mr NewGrad, FSMs aren't only usful for parsers
• interaction diagrams, i.e. the swimlanes. Especially useful in distributed systems, so that you can see overlapping processing
• and the name escapes me, but the diagram that shows which processing is done on which machine, and the communication mechanism
• proper use of parallelism design patterns, e.g. as embodied in Doug Lea's concurrency classes. No Mr NewGrad, you shouldn't be using wait(), notify(), synchronized, volatile

bitch please, HW guys discussing SW design topic, is like white people calling eachother niggas

[tggzzz]

A class diagram allows you to deconstruct the problem domain, see the connections, understand what is what. I've seen too much software that was written without the creator taking the time to understand all that.

IMNSHO experience, a class diagram is one of the least informative diagrams.

What is far more useful are:

• state diagrams, i.e. the Harel StateCharts. No, Mr NewGrad, FSMs aren't only usful for parsers
• interaction diagrams, i.e. the swimlanes. Especially useful in distributed systems, so that you can see overlapping processing
• and the name escapes me, but the diagram that shows which processing is done on which machine, and the communication mechanism
• proper use of parallelism design patterns, e.g. as embodied in Doug Lea's concurrency classes. No Mr NewGrad, you shouldn't be using wait(), notify(), synchronized, volatile

bitch please, HW guys discussing SW design topic, is like white people calling eachother niggas

Do you have a coherent point to make, or are you just trolling?

BTW, it might be wise to be a little more humble, just in case your unstated presumptions turn out to be completely inaccurate.

[Howardlong]

A class diagram allows you to deconstruct the problem domain, see the connections, understand what is what. I've seen too much software that was written without the creator taking the time to understand all that.

IMNSHO experience, a class diagram is one of the least informative diagrams.

What is far more useful are:

• state diagrams, i.e. the Harel StateCharts. No, Mr NewGrad, FSMs aren't only usful for parsers
• interaction diagrams, i.e. the swimlanes. Especially useful in distributed systems, so that you can see overlapping processing
• and the name escapes me, but the diagram that shows which processing is done on which machine, and the communication mechanism
• proper use of parallelism design patterns, e.g. as embodied in Doug Lea's concurrency classes. No Mr NewGrad, you shouldn't be using wait(), notify(), synchronized, volatile

bitch please, HW guys discussing SW design topic, is like white people calling eachother niggas

Do you have a coherent point to make, or are you just trolling?

BTW, it might be wise to be a little more humble, just in case your unstated presumptions turn out to be completely inaccurate.

Maybe his CV got rejected...