Effectively learning electronics as a hobbyist? (warning: longwinded!)

[T4P]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

[FreeThinker]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

Yes but does it MATTER? So long as a beginner gets the FEEL of how it works a 70% understanding is more than enough. As his/her experience grows they will come to realise this themselves and adjust accordingly. Bogging them down in unnecessary details kills enthusiasm. 

[djsb]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

Thanks Dave.s for the link. It's changed my way of looking at charge flow (I nearly said current flow). The explanation is useful.
Thanks.

David.

P.S I still believe that water is still a useful everyday analogy. I will replace the word current with charge when explaining to students.

[quantumfall]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

One wrong will do thank you. The main point I make is that a transistor is use as a resistor with control you get the hang of circuits like that.  I was taught that its a base current to collector current ratio that how you use a  bipolar transistor.  A current amplifier device. I think the link is correct in that the depletion region is made smaller but its the injection of electrons a current that makes it smaller not just a voltage.  Perhaps its you thats got it wrong ? and the link is wrong just maybe ?  but I'm not a semiconductor physicist I'm putting it as I was shown on a professional course, as a current controlled device.

[quantumfall]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

Thanks Dave.s for the link. It's changed my way of looking at charge flow (I nearly said current flow). The explanation is useful.
Thanks.

djsb.

P.S I still believe that water is still a useful everyday analogy. I will replace the word current with charge when explaining to students.

Water is a great analogy you do not have a flow of bubbles, sorry I could not resist that djsb a cheap shot.

A charge is intrinsic to electrons and protons maybe other exotic particles, but to me a current is a flow of Electricity, named like electron I think there is a clue their, Just because a current was described to flow from positive to negative as "Conventional" I do not see the reasoning behind that.  Of course its just as valid to use electricity like that if it works as said its an abstraction electrons or lack off electrons it matters not to them.

I'm not trying to be smart, I really think the electron flow is a better analogy.  Enough please. I did post with the wrong name now fixed I think with an edit.

[quantumfall]

Sorry Aldobrandi its been dragged of topic, still its not all bad to have strange ideas slung at you

As a hobby electronics is very interesting and can be very enjoyable.  As a job / profession its riddled with politics, FUD, vested interests and legal traps like all else and more.

[Aldobrandi]

Please do not apologize, I've been pretty silent but I'm very grateful for everybody's insight on charge flow, as it is one of the many points which confuses me (along with grounding). Part of my problem, as was pointed somewhere in this discussion, is that I have to choose what it is that I want as a hobby : in my case, it is practical electronics, in which case I'm going to have to go along with lumped abstractions and many other simplifications in order to enjoy designing stuff (and not apply Maxwell equations every time I'm designing a small circuit). Thanks again for all your answers.

[quantumfall]

Please do not apologize, I've been pretty silent but I'm very grateful for everybody's insight on charge flow, as it is one of the many points which confuses me (along with grounding). Part of my problem, as was pointed somewhere in this discussion, is that I have to choose what it is that I want as a hobby : in my case, it is practical electronics, in which case I'm going to have to go along with lumped abstractions and many other simplifications in order to enjoy designing stuff (and not apply Maxwell equations every time I'm designing a small circuit). Thanks again for all your answers.

Of course you need to understand electronics to enjoy it at any level, myself  I appreciate the physics way of it fundamentally, and use simple abstractions as well of course, thats good enough to be allowed to work on some stuff.   I like the water analogy as a basic , its not perfect it has no electrostatic field that fits easy ( Air filled bladders inside metal tanks work like capacitors  possibly).   You can get a lot done by using simple comparisons, a transistor works as a circuit element like a variable resistor, which it is if you ignore its capacitance, inductance and the internal physics.  You will find it's all analogy even the highest maths is that IMHO

[vk6zgo]

Going back to the original part of the thread,I would suggest that you have a look at  The RSGB Manual & ARRL Handbook.
These are meant for Amateur Radio Operators,but have a wealth of  technical information in them.

As a "Ham",it looks as if I am pushing the hobby upon people,but your National Amateur Radio Society may be a good resource.
I am not sure if they publish a "Handbook" of a similar type,but they could be worth checking on.
Here is the website:

                                http://www.ref-union.org/

[vk6zgo]

I usually strongly advice against this site/book. The reason is http://www.allaboutcircuits.com/vol_1/chpt_1/7.html

In this series of textbooks, I have committed to using electron flow notation.

Wow, that is terrible.  That is probably the worst thing I have ever seen in the introduction to a textbook.  It is like "warning: this book is wrong, and will confuse you for the rest of your life"

For any newbies out there who aren't convinced or have sympathy for the "electron flow model:":

If you find conventional flow confusing or backwards, your thinking is wrong, you should try to fix it.  In particular, you shouldn't think about electrons.  They are unimportant and unnecessary distrations to electronics.

If you do ever get into semiconductor physics you will have to consider carrier motion.  At that point you will discover that both positive and negative carriers exist, and that you can't ignore either.  Until you get there, you can do 99% of all electronics, including using (but not constructing) semiconductor devices without paying any attention to the existence of electrons.

Spoken like a true Engineer!

"Conventional" current flow is a historic accident!
The decision was made to  say "Current flows from positive to negative" because it was a convenient concept.

Professional Engineers have always been taught Conventional Current Flow,& that is the way they think about it.

Many other people were trained using Electron Flow.
In a Vacuum tube,there is no other form of charge carrier present,so if Electron flow isn't how things work,they would not function.

Positive charge carriers in Semiconductors,or "holes" are really just a spot where an Electron is missing,but they act in every way like a carrier,so you can design things assuming they are.

In normal conductors Electron flow is a logical way of visualising current flow.

In most cases,it doesn't really matter,but if you are going to be a hobbyist,be aware that most of the more useful  books you will use assume Electron Flow.

[amspire]

Many other people were trained using Electron Flow.
.....

Not really sure the point you are trying to make.

Even if you have a nice little diagram showing electrons going from negative to positive, current always flows from positive to negative. There is just no such thing as a SI unit for Electron Flow Current, and if you did make up such a thing, you are going to get very confused.

Even if you are working with valves, you think in terms of electrons, but the current still flows from the anode to the cathode.

In many ways, I have always though it a lucky thing when the electron was defined as a negative charge rather then a positive charge, as current is just not meant to be a measurement of the flow of electrons. It a measure is the flow of charged particles and it is best not to confuse it with the specific case of electron flow.

The notion of current flowing from positive to negative is more then a convenience, current does flow from positive to negative, and to try and say anything else is simply confusing.

No book on electronics will have current flowing in any other direction then from positive to negative. They will have diagrams showing the directions electrons are moving or drifting, but that is different. No equation for Ohm's Law will ever say V = -I x R.

Richard.

[jpc6204]

Do the same with a simple  resistor divider , add a transistor, picture it as a variable resistor (Transfer resistor),  you get the idea . Learn its a current controlled device unless its a FET !  OK You are starting to get the feel of it now....

WRONGWRONGWRONGWRONG !
http://amasci.com/amateur/transis.html

I've never seen this link before - thanks for sharing.  As a PhD in semiconductor physics I can confidently say this is the best (non mathematical) description of a BJT I've ever read.


Jeff...

[m12lrpv]

Hi Aldobrandi,


As a new hobbyist myself I found that the greatest learning motivator is to pursue a specific project that takes your interest.

Years (decades) ago as a kid I tried to play with electronics but never "got it". It just didn't gel in my head because I just couldn't see the point of it. It made no sense. I didn't understand why I needed to know how things work.

But recently I was introduced to the arduino's and as a programmer it was a fun tool that I wanted to play with.

But that fun tool finally gave me a reason to use and understand electronics.

It provided me with ideas for projects that I wanted to build and the micro overcomes limitations in electronics knowledge by allowing me to let the microcontroller do the things that could otherwise be done with regular electronics but which is beyond my current electronics understanding.

Having ideas for micro controller projects led me into other things and I've spent more time learning general electronics than I ever thought I would. Playing with metal detector circuits, LC meter circuits, oscillator circuits, audio switches.


And then there's the IC's that are out there.

I had the opportunity to purchase a stack of IC's on the cheap from Indonesia while on a work trip so I googled around and came up with a list of IC's to get. Comparators, op amps, shift registers and 4000 cmos chips. Then it was a matter of finding projects to use them in or simply to build circuits to test that they actually worked.
This led me to appreciate the wonderful world of application notes  ( and a few IC's that I still cannot figure out good uses for  )

Moving on from those simple IC's to the more complex ones like clock ic's (and soon digital pots) which need to be interfaced with led me into learning I2C and SPI communication.

So that's my tale.

I'm learning because I found something within the electronics world that ignites a specific interest and has me dreaming up projects. Pursuing those projects has the effect of giving the electronics purpose in my mind and made it something that I am self motivated to learn.

Hopefully you can get something from all of that to apply to your situation.

[Bored@Work]

Spoken like a true Engineer!

"Conventional" current flow is a historic accident!
The decision was made to  say "Current flows from positive to negative" because it was a convenient concept.

Professional Engineers have always been taught Conventional Current Flow,& that is the way they think about it.

Many other people were trained using Electron Flow.

I start to repeat myself. No, it is not about Engineers or not. It is about communication. Almost 100% of those taught electronics beyond the very basic levels these days are taught conventional flow. Almost 100% of books, datasheets, literature, use conventional flow. The notation is so perversive, no one mentions any more that they use conventional flow. It doesn't matter if it is a historical accident, everyone knows it is, and still it is a model that works and is accepted.

Teaching people the "real" flow in a non-trivial electronics course is depriving them of easy access to current and historic literature and complicates their life just so the teacher can vent a personal spleen.

In a Vacuum tube,there is no other form of charge carrier present,so if Electron flow isn't how things work,they would not function.

No one claims otherwise. And still the current flow is by definition in the opposite direction. Current in electronics is an abstraction, a model, a simplification, whatever you call it, it is derived from the physics, but doesn't claim to exactly represent the physics. And even physicists these days use conventional flow most of the time, unless they need to wade knee deep through nuclear particles and that stuff.

[vk6zgo]

Spoken like a true Engineer!

"Conventional" current flow is a historic accident!
The decision was made to  say "Current flows from positive to negative" because it was a convenient concept.

Professional Engineers have always been taught Conventional Current Flow,& that is the way they think about it.

Many other people were trained using Electron Flow.

I start to repeat myself. No, it is not about Engineers or not. It is about communication. Almost 100% of those taught electronics beyond the very basic levels these days are taught conventional flow. Almost 100% of books, datasheets, literature, use conventional flow. The notation is so perversive, no one mentions any more that they use conventional flow. It doesn't matter if it is a historical accident, everyone knows it is, and still it is a model that works and is accepted.

Teaching people the "real" flow in a non-trivial electronics course is depriving them of easy access to current and historic literature and complicates their life just so the teacher can vent a personal spleen.

In a Vacuum tube,there is no other form of charge carrier present,so if Electron flow isn't how things work,they would not function.

No one claims otherwise. And still the current flow is by definition in the opposite direction. Current in electronics is an abstraction, a model, a simplification, whatever you call it, it is derived from the physics, but doesn't claim to exactly represent the physics. And even physicists these days use conventional flow most of the time, unless they need to wade knee deep through nuclear particles and that stuff.

So all these people are more stupid than First Year Technical Trainees,& can't quite understand that Electron flow is how it really works,& for historical reasons Conventional Current Flow is used in most calculations,& such things as "Right  hand rules",etc.

People in basic Electrical Courses saw this relationship & quite easily worked with it.
It usually took a Lecturer about 3 minutes to explain it to the satisfaction of everybody in the class.
Pretending that Electron Flow does not exist is more likely to cause confusion than to acknowledge it & also point out that Conventional Current Flow is in much more common use.

You in fact,"vented your spleen" in a complete over reaction to the original posting re the particular link.
You could have just pointed out,in a pleasant way,that Conventional Current Flow was the standard,but then again,I forgot,you don't do pleasant!
 

[vk6zgo]

Many other people were trained using Electron Flow.
.....

Not really sure the point you are trying to make.

Even if you have a nice little diagram showing electrons going from negative to positive, current always flows from positive to negative. There is just no such thing as a SI unit for Electron Flow Current, and if you did make up such a thing, you are going to get very confused.
I didn't think SI units cared one way or another!

Even if you are working with valves, you think in terms of electrons, but the current still flows from the anode to the cathode.
& how, pray, does it do this?

In many ways, I have always though it a lucky thing when the electron was defined as a negative charge rather then a positive charge, as current is just not meant to be a measurement of the flow of electrons. It a measure is the flow of charged particles and it is best not to confuse it with the specific case of electron flow.

The notion of current flowing from positive to negative is more then a convenience, current does flow from positive to negative, and to try and say anything else is simply confusing.

No book on electronics will have current flowing in any other direction then from positive to negative. They will have diagrams showing the directions electrons are moving or drifting, but that is different. No equation for Ohm's Law will ever say V = -I x R.

I can't see what you are getting at--Ohms Law really only applies to the amplitude of the  components & doesn't have anything to do with the type of current flow you are using as your convention.
Yes,some books do show Electron flow


Richard.

It seems, that as Bored At Work says, Conventional Current Flow has become so  all pervasive,that people have forgotten the existence of Electron flow.
Many Technical publications over tens of years used Electron Flow as an alternative to Conventional Current flow.
The OP is quite likely to come across some of these books.

[quantumfall]

Conventional current flow it seems a fudge.  The standard measure of current is the ampere an SI unit, which is one  coulomb per second  (an SI derived unit ) or 6.241 × 1018 electrons per second. what more do you need as proof than that. "Current" is not an SI Unit.  If you say you use Amperes you are talking about electrons no question about it.

jpc6204 "As a PhD in semiconductor physics I can confidently say this is the best (non mathematical) description of a BJT I've ever read."

I would like to ask , Is it a voltage controlled device , will it work, switch on without current flow (like a FET gate, lets forget the initial charge on the gate here thats needed.)  in its base terminal ?

Is it a current controlled device (As I was taught) a voltage controlled device or are both of these the  wrong to look at it ?

[saturation]

Learning electronics requires a properly laid out curriculum, just like learning to read you need to know the letters before the words, before sentences.

R,L,C, RLC networks, diodes, transistors, FETS for example, in that order.  Most textbooks are laid out that way, but few,  have the detail to make full working circuits.  I think other posters have mentioned the sequence.

If you jump around, you'll have the equivalent of a phrase book.  If you mix and match phrase books and practical theory, you'll have the Rosetta Stone.  It won't make you fluent, but you can get by.  But to have real control over it, you have to understand all the working parameters of each component from a practical point of view, i.e. at least the lumped element model.

[KD0CAC John]

How to learn electronics , for beginners .
Start with opposing the masses .
I've been doing it for 58 yrs. , thanks , now I can say I told them so
I'm waiting for that link so sink in , bookmarked , thanks again .
John
KD0CAC
73

[pickle9000]

Wow nice topic, I started with a 100 in 1 kit from Radio Shack (over 40 years ago). You can still buy versions of the kit. From there I went to the Forrest M Mimms books.

Do you get enough from that kind of material? No, but it's hands on and is a great primer. I still pull out the kit and use it on the bench with the nieces and nephews.

The reality is that electronics is a very large field, you can't know it all. You need to reeducate regularly for most projects. I get to learn new things all the time, it's the best. I do get paid for my work but I love it as much now as when I was 10. It does take time to be proficient but remember you need to blow a few things up to get better. Nothing like the smell of burning semiconductors.

Put a basic bench to together, meter, scope, signal gen and so on. It's makes things much easier. If you get it wrong, no problem, just start over.

Good luck to you.

...mike

[jpc6204]

jpc6204 "As a PhD in semiconductor physics I can confidently say this is the best (non mathematical) description of a BJT I've ever read."

I would like to ask , Is it a voltage controlled device , will it work, switch on without current flow (like a FET gate, lets forget the initial charge on the gate here thats needed.)  in its base terminal ?

Is it a current controlled device (As I was taught) a voltage controlled device or are both of these the  wrong to look at it ?
[/quote]

At a device physics level it is a voltage-controlled device.  BJTs deal with PN junctions and FETs deal with metal oxide semiconductor (MOS) interfaces - both have charged carriers (electrons and holes) and charge is moved by potential gradients (voltage).  For MOS structures you have an insulator in the way so no current flows (excluding oxide tunneling current) when a potential is applied to the gate.  In a PN junction (think base-emitter junction in a BJT) there is no insulator, just a depletion layer.  The depletion layer reacts to an applied potential (voltage).  Once a potential (voltage) overcomes the junction, current will flow. So yes, you will have current flowing at the base when a BJT is on, however you must have an applied voltage for any of this to occur.

Consider a solar cell.  Photons from the sun are directly converted to free carriers (electrons and holes) in the depletion region of a PN junction.  These free carriers move within the depletion region (ie. current).  This generation and movement of free charge carriers does not affect the depletion layer, nor does it "turn on" the solar cell.  Solar cells are not on-off devices.  If the generation of free charge carriers and its subsequent movement (ie. current) turned a solar cell off or on we would have a problem. 

Hope this helps.


Jeff...

[Aldobrandi]

Thanks a lot jpc6204 for this post, it clarified a lot of things for me (I wasn't particularly fond of the rather agressive style of the author of that article (albeit an informative and eye opening one!) on http://amasci.com/amateur/transis.html). For some reason, I can't feel like I have a good understanding of how to use a device in a practical fashion if I don't have at least a basic theoretical understanding of it on paper: I always need at some point to come back to the physics. But I am still incredibly new to all this, so maybe in a decade or so of working on circuits, I will have a much more symbiotic relationship with theory

Thanks again for the incredibly enlightening discussion. And please keep the stories of how you came to electronics (either as a hobby or as a profession) coming, I find them all very very inspiring.

[jpc6204]

Aldobrandi - I find myself in similar shoes.  I have a very good theoretical understanding of what is going on in each chip, I just lack practical experience putting everything together in a circuit.  I just graduated a year ago and realized that I need to learn more.  I bought some electronics and Arduino books to help round me out.  I still have a long way to go.  Don't worry about what you know or don't know, just make sure it's fun.   The beauty of this forum is there is a a great group of people who will have answers for questions that we have (no matter how silly they are).  15 years ago learning electronics would have been very different.

Best of luck with all your electronic adventures!


Jeff...

[quantumfall]

jpc6204 "As a PhD in semiconductor physics I can confidently say this is the best (non mathematical) description of a BJT I've ever read."

I would like to ask , Is it a voltage controlled device , will it work, switch on without current flow (like a FET gate, lets forget the initial charge on the gate here thats needed.)  in its base terminal ?

Is it a current controlled device (As I was taught) a voltage controlled device or are both of these the  wrong to look at it ?

For MOS structures you have an insulator in the way so no current flows (excluding oxide tunneling current) when a potential is applied to the gate.  In a PN junction (think base-emitter junction in a BJT) there is no insulator, just a depletion layer.  The depletion layer reacts to an applied potential (voltage).  Once a potential (voltage) overcomes the junction, current will flow. So yes, you will have current flowing at the base when a BJT is on, however you must have an applied voltage for any of this to occur.

Hope this helps.


Jeff...
[/quote]

Obviously for a current to flow their has to be a voltage I can see that, but once the junction voltage is overcome the BJT is then controlled by the current  into the base.

Their has to be a voltage I can see that about 0.8V  to make the base conduct, but after that the control mechanism is a current correct ?  as I was taught. It is misleading to call it a voltage controlled device in the WRONG WRONG WRONG WRONG reply I so kindly received.  Collector current is in a ratio to base current not voltage across the base, correct ?  Even a FET will have a small current to charge the gate at first, its capacitance I suppose, but minute so its not counted normally.

[MrPlacid]

Op, this is longwinded too.

I remember back then when I first got into electronics and scrounged youtube for videos. That was where I saw dave who just got started blogging.

As I study electronics, I always keep in mind of my journey through programming, and how I suddenly understood it one day. I was hoping a similar thing would happen. I saw alot of parallels between the programming and electronic worlds. However, I must admit that learning electronics took much longer. The reasons are in the next few paragraphs.

One is that visualization of the components such as inductor, capacitor, conductor, etc.. The visualization also must make sense with their formulas. If it breaks the formulas, it's back to square one of finding a better visualization for that component or accept magic. When the books tell us to visualize capacitor as a water tower, the question is why? They often don't go into the details other than tell us to do so.

Two is the electronic lingo. Back then I was lost over mere things like coulomb, volt, amp, cathode and anode (this is opposite to the chemistry's ones), current direction, input impedance, output impedance, high, low, RMS, etc... . Books and engineering gurus used them like normal talk. I remember seeing the book use something like "high input impedance" then I check back if they even explain that. This put us hobbyists in a "I think it means this, but I am not 100% absolutely sure" state.

Third is to actively learn. This is where it gets expensive in both time and money. When you see them talk about a circuit, build a simplify version of it and test it. Reading about it is the same as watching the cooking channel all day long and walking away still not knowing how to cook.

Anyways, it's not the best way to study electronics, but below (pic) is how I study electronics as a hobbyist. As I read or watch the gurus' videos, I come up with study materials. Then I enter my materials into my personal study site. (site address is undisclosed, but there are many good free study sites) This has help me greatly. Us hobbyists don't do electronics everyday nor even weekly, so something to refresh the memory is good.