Warning Do not get a qualification with ICS Learn in the UK (BTEC L3)

[G0HZU]

You can also see why this sexy dual gate device made the single gate N channel depletion mode 'IGFET' devices obsolete fairly quickly in the late 1970s and early 1980s..

By using it in dual gate mode you can use it as a variable gain, cascode amplifier by applying the signal to gate 1 and then feeding a decoupled dc voltage to gate 2.

If you then change the gate 2 voltage higher you can see how much steeper the upper transfer curves are on the graph. The top curve is for gate 2 at 4V dc. So you get more gain at higher gate 2 voltages. So you can set the gain according to the dc voltage level at gate 2.

You can also use it as a mixer if you ac couple an LO signal to gate 2 instead of the variable dc voltage. This is because the ac coupled LO signal 'varies the gain' at the rate of the LO frequency and this gives the non linear mixing effect. You could do the same thing with a +/- dcV fed potentiometer at gate 2 if you could wiggle it up and down as fast as the LO frequency!

[Precipice]

Yeah, I just bought a reel of Siemens BF 1012* dual gate FETs to have a play with, a couple of weeks back. Not depletion mode, though, so I think if we want to chatter about our adventures with tetrodes, we ought to fire up a new thread for it and leave Simon's alone?

I was going to knock out a little PCB with connectors and support gubbins, since SOT-143 is a bit of a pain to breadboard, and if this device promises 1GHz, I'd like to at least get near.

* Datasheet starts with
Silicon N-Channel MOSFET Tetrode
•For low noise, high gain controlled
input stages up to 1GHz
•Operating voltage 12V
•Integrated stabilized bias network

[Wilksey]

All distance learning facilities in the UK are useless, may I ask why you want to complete a BTEC? I have a HND in electronics and computer engineering, and never wanted to go to degree level, I got a few books, one of which was the Art Of Electronics, and now 10+ years later, I am glad I didn't go to Uni to do the 1 year top up to a degree level.  People I work with have PHD's in various subjects, usually robotics and I find myself teaching them things about how to calculate Op Amps and the like.  I think with a subject like electronics that experience speaks volumes over a educational qualification.

P.s. I think I bought some LED's from you off of E-bay, I didn't realise you were a moderator here!

[eneuro]

The only other course available by distance learning is a HNC and there are few of these as well.

I like those online MIT courses series MIT OpenCourseWare and then  it and hopefully physics works without any certifications 

[bwat]

All distance learning facilities in the UK are useless, may I ask why you want to complete a BTEC? I have a HND in electronics and computer engineering, and never wanted to go to degree level, I got a few books, one of which was the Art Of Electronics, and now 10+ years later, I am glad I didn't go to Uni to do the 1 year top up to a degree level. 

University is about being introduced to ideas and people you wouldn't otherwise. The internet has introduced the ideas part to people who don't go off to uni so maybe that's not so important these days, but the people part is never going to be replaced even by videos. I once took a course where there were only five or six students and the lecturer was a genuine pioneer in the subject. With so few students he could tailor his lectures to us individually and we could ask stupid questions without disturbing the whole group. One of the things you realise when you come into contact with proper experts is that they're human too. It makes it all much more achievable knowing that.

People I work with have PHD's in various subjects, usually robotics and I find myself teaching them things about how to calculate Op Amps and the like.  I think with a subject like electronics that experience speaks volumes over a educational qualification.

It's probably not an effective use of their time to learn to do the calculations and your time is probably much cheaper. They have their specialisations and you have yours.

[Wilksey]

University teaches you how to research, and the only time a question is stupid is if you already know the answer but can't think, then it becomes obvious when someone tell you the answer.
Some people benefit, but what you also have to remember is that the lecturers don't know everything, they only know what they have learnt themselves, everything else is just a guess, or found on the internet, and most of the lecturers I have come across don't know anything else but the basics, unless in a specialist area such as robotics, then they might know the best way to drive a multitude of motors.
Sometimes as well as realising that the "experts" are human, it also helps to realise that sometimes there is a huge team and resource behind said expert, that also helps a lot!

If you work out the basic rate per day for a person mine is a lot higher than the PHD people as I have worked my way up through the years, it's just down to experience rather than specialisations.

[bwat]

you also have to remember is that the lecturers don't know everything, they only know what they have learnt themselves,

This is true of everybody, no? How can we know that which we have not learnt?

everything else is just a guess, or found on the internet, and

I think we have experience of quite different lecturers and quite different subjects.

most of the lecturers I have come across don't know anything else but the basics, unless in a specialist area

This can be said of most specialists in the modern world.

[Wilksey]

Yes, but a lot of students know bugger all before going to these lectures, those of us that do / did find themselves not taken any notice of, more of a "how dare you correct me" kind of attitude in my experience.

I studied electronics and computer engineering, and that was my experience.

What I mean regarding speciality subjects is, if you have a PHD in robotics and get a job doing robotics, great! Most of the time this doesn't happen however, so we have robotic PHD students doing general electronics, tasked for example, with designing a PSU and can't do it, it's not their fault, don't get me wrong, I am not saying they SHOULD know it, or that I have any objection to helping them, I am just saying that University and degrees, PHD's and the like are not the bee all and end all of it.

I did further education myself, do I regret it? No, would I recommend it? Yes, if that is what you want to do.  Did I learn anything? Yes, did I get a better job because of my qualifications? No.

Times may have changed, but when I was looking at the options of further education (Uni) or getting a job, employers were more concerned over experience and "can I do it" rather than "have I learnt about xyz, or can I find out how to do it".  Tinkering and hobbying helps of course as you gain valuable experience from actually doing something, and it's no fun unless you blow up a capacitor or two!

[bwat]

I don't think you and I are a million miles apart in our views here. My claim is that university is about exposure to ideas and the people who are genuine experts. I specifically avoided mentioning the qualifications because I don't think it's that important, and like you, I too have worked with people who have the qualifications but not the ability to deliver solutions to everyday problems.

[AndyC_772]

I too have worked with people who have the qualifications but not the ability to deliver solutions to everyday problems.

These are two different requirements which suit two different kinds of problems, though.

The example I usually cite is one which also crops up in the perennial 'engineer vs technician' debate also, and it's comparing an automotive technician (ie. a mechanic) with a mechanical engineer.

The mechanic is, of course, the person you'd go to if your car's engine breaks and needs to be rebuilt. You need someone with a lot of real-world practical experience in getting engines apart, identifying and replacing failed components, and getting it all put back together according to the specifications in the service manual. It's a highly skilled job by any standard.

By contrast, the mechanical engineer might not have a clue what to do when faced with the first seized bolt. But that's not the engineer's job; the engineer's job is to establish the root cause of that reported failure, and to design that weakness out of the next generation of engine - while, at the same time, making it 15% more powerful and 20% more fuel efficient than the previous generation.

That's not something you can learn 'hands on' in a workshop; it requires a detailed, theoretical understanding of materials properties, thermodynamics, manufacturing processes, CAD and so on, which come from academic study. These are skills which simply don't apply to a mechanic's job, any more than the ability to undo a rusty fastener with limited access applies to the engineer's job.

[bwat]

I too have worked with people who have the qualifications but not the ability to deliver solutions to everyday problems.

These are two different requirements which suit two different kinds of problems, though.

I'm talking about people with degrees that can't solve the type of problems that others with similar degrees can. I've met CS graduates that didn't know what Amdahl's law was. My undergraduate studies were as theoretical as they get  and even I was taught that.

[Wilksey]

I may sound old (i'm 31), but I really don't if degree courses are getting easier or if people are just managing to wing them because some of the people (note I said SOME) are really not playing with a full deck!
When I was studying, theory was key and hands on was just a bonus, that is part of the reason I didn't want to go on, I wanted to get my hands dirty in the real world, so to speak!

Some of the graduates I have (I use the term loosely) "worked" with really should not have passed their exams / tests whatever you will because they lack basic fundamental knowledge which, if left to design or even assemble a SMPS for example could seriously injure themselves, maybe it's just a lack of common sense, but whatever it is, I don't know how they passed.

Now, on the other hand I have met some really clever graduates that want to learn more, admit they do not know everything and will take the time to learn and are actually pretty darn good at what they do, some of their ideas, in line with what bwat has said, are superb and I would never have thought of some of them.

If you have just left school and want to go on to further education then I would recommend it if that is what you want to do, if you are already in work and you require a qualification for whatever reason for work purposes, or if they are willing to pay for it (hey it's free, why not!) then go for it, if it is just out of boredom or you want to learn something new, I would not personally have thought it worth going to Uni / College etc.

In terms of different problems and requirements, that is also correct in some sense, I would not trust a software engineer to program my FPGA, on the other hand, there are some software engineers that could program one better than I could, so it really does depend on the individual.

I for one try and have a go at anything if it is safe to do so, if I mess it up then so be it, i'll either try again or give up depending on if I really don't think i can do it.

[G0HZU]

I did some digging to try and find a datasheet for a suitable old school N channel D MOSFET and found the classic 2N3797 from Motorola. This device probably dates back to the 1970s. I don't have one here to prove it and these old devices now cost a lot of money to buy if you look on ebay.  £10each buys you this little slice of history...

You can see in the snippet from the datasheet below that this device has the correct transfer characteristic. i.e it has a small drain current of about 3mA  flowing when Vgs is 0V. Therefore, if this classic old device were fitted to the circuit given in the assignment then I think the circuit WILL work as a small signal amplifier despite all the criticism from Simon on this thread and also in his video and the other eevblog thread here:

https://www.eevblog.com/forum/projects/'subject-matter-expert'-required/.

the FET amplifiers were even more badly explained and infact their common source amplifier is incorrect as it has no biasing so clearly the course author is an idiot

The diagram that corresponds to the circuit was posted earlier by another member, 1st page of the thread in "davecad" (TM), it has been agreed that the diagram does not constitute an amplifier



Fact is that is not a valid amplifier circuit

they have supplied a diagram of an AC coupled NOT gate

not my fault if they gave me a stupid diagram that don't work

Can you truly call that diagram an amplifier.

(yep, it's not an amp)

Obviously, if you fit the correct device (i.e the correct N channel depletion mode device as depicted by the circuit symbol in the assignment) then the circuit WILL work as a small signal amplifier.

So Simon is clearly wrong to criticise the course material here and also, the BTEC tutor can not be labelled an idiot for releasing this FET circuit on the course.

The plain and simple fact is that Simon made the error of using the wrong type of MOSFET and then threw a tantrum on youtube about the quality of the course and insulted the tutor(s). Was that wise?

[8086]

Simon, take this from another Simon, no matter how smart you think you are, do as you're asked and make no assumptions on a course like this.

Don't criticize the content unless you are absolutely, 100%, totally, completely sure you are correct and they are wrong.

You did what many people do, and you let yourself become your own worst enemy.

With respect, you screwed this up.

[fcb]

I tried to watch the first 30 seconds of Simon's video, but it was just to quiet - any chance you can repost the video with the levels sorted.

[G0HZU]

Simon, take this from another Simon, no matter how smart you think you are, do as you're asked and make no assumptions on a course like this.

Don't criticize the content unless you are absolutely, 100%, totally, completely sure you are correct and they are wrong.

You did what many people do, and you let yourself become your own worst enemy.

With respect, you screwed this up.

Yup... MOSFETs can easily catch anyone out because there are so many flavours of them and lots of associated symbols.

In my day I was taught the way to reverse engineer each MOSFET circuit symbol because the symbol consists of various clues to actually tell you what the device is and (more critically) how the channel behaves electrically. i.e. there is critical behavioural information locked into each symbol. Once you know this you can often tell at a glance if the circuit is valid or not.

[Mechatrommer]

"assuming" the OP claim is valid even though he didnt provide any hard proof, esp lecture content and lecturer/tutor proficiency.... either way anyway, as someone said, mission failed or directive unacomplished. its about putting the ego aside and play with the rest. there are more than skills and knowledges, things like humble, respect, willing to ask and discuss politely or simply shut up no matter how foolish the person you are facing at, esp your tutor where your fate is lying on him. now dont get me wrong i wont encourage but licking either, there are people who want to make money for a living, there are people who want the scroll for a better place, in the end both will get win win situation. if you think its a fraud? then dont do it, you get the scroll. you explained to them but they didnt listen, then leave, you get the scroll. ego aside, you get the scroll, mission accomplished, directive accomplished, otherwise its a failure no matter what mr anakin says.

back to the question, i'm nearly went mental to find amp circuit in "task 1 c", with higher level of concentration then i found its actually "task 1 question 3 c", i dont see any problem, the directive is to explain the circuit input and output result in plain verbal tone level, if its not working, then explain why (or simply say i dont know why as most normal kids will say anyway) in plain verbal tone level, if you have better suggestion (to prove your proficiency) then please do so in plain verbal tone level, thats it, whining is not required. that shows your profesionalism and to avoid being seen as a "foolish whiner" no matter how briliant you are (or think you are).

and think my last point is.... expecting an "engineer" or "a professor" to know how the "dirt bolt and nut is" or "dave should be able to fix any tv because he is an engineer" is a foolish thought no offense its just plain truth. just because you have not living the life doesnt necessarily put you in an "absolute truth" position. i dont think i want to explain further why, others have tried.