Electronics > Beginners
Transistor, i hate you!
phiza:
Finally i registered on this forum!
Bonjour,
i'm nerd, a passionate student of ee and i quit job two months ago to close my self in my bedroom/lab trying to make something beautiful. (I know it sound a bit crazy but it's true and i'm start to think that maybe i've made a mistake :-DD)
I spent some money on RS, Mouser, TME, Amazon and eBay to get parts and tools that i needed for this specific project.
I hate transitors, i think that i've never understand 100% how they work. I mean i can use them for simple task, sometimes they are essential. But generally speaking if i can choose between two different design and one involves transistors the other no, i choose the second one. Even if that choice change radically the design i.e introducing an ADC, i'm ok with that, i mean it's my comfort zone.
First of all no beta matching problems and no need of temperature compensation.
Well but that isn't the biggest problem by my point of view...i mean, for example, it's about two week that i try to use the Ebers-Moll equation to get, with good approximation, an exponential response of the collector current Ic by varying the Vbe in certain circumstances. It's easier to me to get an exponential response of the Ib (i use only one transistor, regardless of temperature).
Sometimes it work, sometimes don't (even on Multisim or LTspice). I can't write a standard project method. Seems that to achive a good design with transistors you have to try all possible combinations and finally get a special secret formula and it look like a Chili recipe.
What do you think about it?
cheers :D
some links:
https://schmitzbits.de/expo_tutorial/index.html
https://www.allaboutcircuits.com/projects/diy-synth-series-vco/
https://northcoastsynthesis.com/news/exponential-converters-and-how-they-work/
https://xonik.github.io/theory/vco/expo_converter_1.html
Zero999:
Hello and welcome to the forum.
Which type of transistor are you struggling with? There are two main types: field effect and bipolar? I assume you're talking about the latter, as you've mentioned beta and the Ebers-Moll equation.
Please post some example circuits which you've struggled to understand.
What job did you quit? How are you paying the bills now? Savings? Living with your parents? I think you've made a mistake if you're planning to make a living by building something in your bedroom and selling it.
Do you have any formal qualifications in electronic engineering? You'd be better off studying, than building something in the lab and not working./
phiza:
Hi
many thanks for the quick reply
I'm using BJT (2N3904, BC547 mostly)
I'm a part-time student in EE at the University of Pisa and have a high school diploma in Electronics and Telcom.
Savings mostly and small jobs for the neighbors, i was a PLC developer always away on FCA Plant. Anyway i don't like it, i was also a IoT Hardware developer for a small company in Rome, but they paid me less. That's really was a mistake, quit a nice job for money.
Thanks.
PS:
the second transistor is not correctly polarized.
Dave:
Why do you assume the second transistor is not correctly polarized? :-//
It has enough base current to go into saturation, everything checks out.
phiza:
Because second transistor Vbc is >0, to be in forward-active region shouldn't be <0 ? (and Vbe>0)
[Please don't kill me :D]
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