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Understanding the Transistor Amplifier

Discussion in 'General Electronics Discussion' started by Cham, Oct 26, 2015.

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  1. Cham

    Cham

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    Aug 11, 2015
    My experience in electronics is that of a senior in high school that has patrolled these forums a little bit and has taken a digital electronics course that was more focused on logic gates and basic V=IR stuff than anything. For a new project I was looking to work with transistor amplifiers and I haven't the slightest idea what I'm doing. I understand the basics of the base, collector, and emitter pins in a switch transistor, but have no idea how to use that with an amplifier. I would be very appreciative if you could shed some light on the topic. Simplified, my question is "What do the pins do on an amplifier transistor?"
     
  2. hevans1944

    hevans1944 Hop - AC8NS

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    Using a transistor as a linear amplifier, instead of using it as a switch, takes you into the wonderful realm of analog circuit design. I suggest you go to the library and check out some texts that will guide you. One of my favorites now (it wasn't written yet when I started my career) is the "Art of Electronics" by Paul Horowitz and Winfield Hill, now in its third edition and published by Cambridge University Press, available here from Amazon. "The ARRL Handbook for Radio Communications" published yearly by the American Radio Relay League (ARRL) has a brief but practical section on analog amplifiers as well as covering most of the theory and practical instruction you would need to begin a career in electronics.

    And you will need to set up an "electronics laboratory" where you can experiment with circuits. Why experiment? Because the pins on an amplifier transistor do more than just support the device above the circuit board. The best way to find out is to experiment: construct, test, measure, write down what you did, what you discovered, what works, what doesn't work. Years later, if you stay in electronics, a review of your notes will delight and amaze you.
     
    Martaine2005 likes this.
  3. Martaine2005

    Martaine2005

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    There are also plenty of very long threads on here ALL about transistors....Shhh...:p

    Martin
     
  4. Colin Mitchell

    Colin Mitchell

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    I have a large eBook on THE TRANSISTOR AMPLIFIER and I approach it from a completely different angle than any text book.
    22,000 have read the article and they say they have never been so informed.
    It's a non-mathematical approach because no maths can be applied as a transistor comes in batches with characteristics so divergent that you have to make a circuit flexible so you can use any transistor out of a batch.

    http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html
     
    wingnut likes this.
  5. wingnut

    wingnut

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    Aug 9, 2012
    Colin, your eBook is fantastic because it is non-mathematical, for the non-mathematical like me.
     
  6. Colin Mitchell

    Colin Mitchell

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  7. Cham

    Cham

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    Aug 11, 2015
    Thank you everyone! I'll check out the eBook and the library today to see what I can find.
     
  8. Cham

    Cham

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    Aug 11, 2015
    I'm glad you brought up the note-taking aspect because I really need to work on documentation in general. Thank you!
     
  9. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Uh,,..yeah. He can go there but I would strongly recommend that he first wrap his head with heavy duty duct tape.:p
    ****************************
    Collin.... You're plugging again. :rolleyes:

    Cheers,
    Chris
     
    Martaine2005 likes this.
  10. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    I have never adequately documented any project the way I thought it should be done: provide enough information to allow it to be reproduced and maintained. Ideally, this documentation would include a theory of operation section explaining how the project works, a set of schematics and/or wiring diagrams, a bill of materials with sources where unusual parts could be purchased, and some photographs.

    I didn't do any of this stuff because I never created anything but "one-offs," mostly for other people's projects. Once my part was finished there was never any time available to go back and "finish" the documentation. All I had were my notes, some sketches and perhaps a few photographs gathered up into a folder and placed in a file cabinet, never to see the light of day again unless I went looking for them.
    Yes he is, but there is a lot to see and learn on his web site so I don't begrudge him the opportunity to blow his own whistle now and then. I wish the information he has gathered together was available in the 1950s when I began this journey. His e-book without math is an especially good introduction to the topology of electronic circuits. Knowing what is possible and some ways to achieve it is the first step to learning. The theory and maths will come later as needed. It is very important to do rather than just read.

    Early in my career I wanted to become a radio amateur and build my own "stuff". So I read a lot of articles in QST magazine and marveled at how professional the "amateur" constructions looked in the photographs. It wasn't until many years later that I found out almost none of the projects in QST were actually "amateur" constructed. The photos were professionally lighted, and retouched if necessary, to show everything in the best light possible. What finally tipped me off was the fact that there were no mistakes in the constructions: no scratches, no poorly placed parts, no bad solder joints, no layout marks, no holes drilled in the wrong places. Everything was perfect. Which was as it should be for a DIY article, but that wasn't the way amateur radio friends of mine did things. They salvaged stuff and literally beat it into submission for whatever goal they pursued. The final result was not pretty. However, it did (usually) work! Lesson learned: done is better than perfect.

    So, take copious notes, make readable sketches, document what you can, but always remember to do something, not just read about it.
     
    CDRIVE likes this.
  11. Martaine2005

    Martaine2005

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    I totally agree.
    After all, we are all guilty of linking to another web site for a tutorial for example!
    Colin's site helps me because (not all) the math, calculations, formula are not critical. If a 1K doesn't work, try a 2.7K for example. Or use anything from a 1K to 20K. All these points are extremely important to the new comer like me. It's far easier for me to see the outcome rather than calculate it.
    Once the desired circuit works, then we can work on it to accomplish a more stable , less current hungry circuit...
    We all have to start somewhere. I have two major problems, math and the ability to explain technically what the components are doing.
    Although I understand, I am not at a level to just say "reverse bias" that because of this....But I know why it's there..

    Martin
     
  12. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Just to clear the air, I don't disagree about the value of Collin's website. Hell, last year I purchased his PIC Programming In ASM kit course. I thought it had value or I wouldn't have bought it.

    What I'd like to see change is Collin's Lone Ranger behavior. He typically rides into a thread, leaves a silver bullet, which is sometimes quite wrong and rides out of town with a hardy "High O Silver"! Rebuttals are never addressed.

    Cheers,
    Chris
     
    Martaine2005 likes this.
  13. Colin Mitchell

    Colin Mitchell

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    "What I'd like to see change is Collin's Lone Ranger behavior. "

    I only give a short answer because I previously gave a long answer and less than 10% of my replies were taken up by the original poster.
    Even now, less than 10% of the replies are taken up or advanced upon.
     
  14. Martaine2005

    Martaine2005

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    That was another issue I pointed out when I joined here.
    Hi Ho and no silver lining....
    We are all different and need to be treated that way. The technical terms come later..
    I will say say "shave a bit there", the poor kid touches his chin!.
    Or to use a diode as an example, it works one way or breaks down the other.
    Forward bias, reverse bias.
    Using a router will give the same results. Most spin clockwise, so pushing it will damage your work with external cutting.
    However, cutting internally is the oposite with a fence or guide bush.
    Clearly you woke up ok and didn't feel the need to alter your psychic post! "in the morning".

    I am still trying to catch up! To that point where I know what was said in the morning...:D

    Martin
     
  15. Colin Mitchell

    Colin Mitchell

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    At least this website gets a number of inquiries each day.
    Everyday Practical Electronics, the only magazine left in the UK gets 3 PER WEEK !!!
    It is on its last legs.
    And the same with Elektor.
    No-one has provided a .pdf of the magazine since July !!!!
    If I told you I would invent something that stopped the presses, you would not believe me.
    It is the internet.
     
  16. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Now that's much better. Now we're actually conversing! ;)

    Thanks for the reply.
    Chris
     
  17. Cham

    Cham

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    Aug 11, 2015
    Hey everyone, sorry for my inactivity within my own thread. I swear I'm reading everything and I very much appreciate all of the time and knowledge you are giving to me. I'm just busy with school, so my research is typically done in those glorious, small pockets of time I get throughout the day. Thank you all!
     
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