Common Emitter Calculations and Circuit Demo

[@pileofstuff]

Thanks for the refresher. It's been a very long time since I went through the full set of calculation in a basic BJT amplifier.

[@jstro-hobbytech]

i think i'm the only one with thousands of pages of notes haha. i kid, but i do. young and retired man haha. there's updates for that pod go you have ehh. that's what someone told me at long and macquade the other day while parting with way too much money. i got a classical gig with another dude for money. he needs a lead player. been years since i played classical cord voicings using just my fingers. i hybrid pick alot when i want to flex and bring a riff back to timing with what im beginnning to think has been a waste of tens of thousands of hours of practice but such is life i guess. haha i use diodes to bias if im in a hurry and depending on voltage rails. you're a great engineer j. i maintain you waste your talent on a platform that doesnt care about you.

[@GadgetReboot]

now I just need to add maybe some common collector stages to improve impedance but that’s a project for another year.

[@jstro-hobbytech]

@@GadgetReboot you can do this stuff in your sleep brother haha. great video.

[@jstro-hobbytech]

@@GadgetReboot an smd transistor logic clock would be cool man. alot of hours in cad though man. like tell the time clock i mean. i went looking for all my transistor notes and they're so spread out 80 percent makes no sense to me haha. when my workshop is finished yet another reno i'm gonna go over everything again and make prettier boards with examples. worst thing about perfboard is you throw it out or parts get bent and they dont work anymore or what you thought once looked good is a massive eye sore. i speak of me obviously haha.

[@TheDefpom]

Very well explained, well done.

[@GadgetReboot]

thanks! I had to relearn some things but it all came together.

[@AhmedAli-op6ng]

Thank you so much. It is the best explanation of the very basic circuit. I always struggled to understand the calculation all the way to end. It was just perfect for me . Please more of such videos starting from basic to advance.

[@sootikins]

Thanks! Very good explanation. It's review for me - review of things I learned 40 years ago, ended up never using, and pretty much forgot. Nowadays, with more time to tinker, this sort of knowledge has become useful to me. EDIT: Aaaaand... this comment will never be seen because KZbin decided it's not worthy of showing up in the default (Top[ Comments) sort. Only shows with Newest First selected. I doubt I will ever understand the method to the madness of KZbin's comment ranking.

[@GadgetReboot]

I think every time I learn how to do the transistor calculations, I forget the op amp ones again so I think I need to review that now.

[@macdaddyns]

Hope you can accept a compliment, I wish you were my Semiconductor 101 prof 40 yrs ago! Excellent Amp tutorial!

[@GadgetReboot]

Thanks! I was lucky enough to have some good teachers including many magazines and books and the Internet as well.

[@TheEmbeddedHobbyist]

Thanks for the refresher, it's been a year since i posted a similar video in my electronics Kit series. 🙂 might be worth pointing out that the power supply acts as a large capacitor which is why (R1 and +9V junction) is affectively seen as the same as 0V or ground to the input AC signal.

[@GadgetReboot]

I remember being confused for years when I would see a circuit analysis drawing equivalent versions where the positive rail was AC ground. I figure I’ll have it all figured out just when I’m ready to give it all up for good.

[@TheEmbeddedHobbyist]

@@GadgetReboot I still have to stand on my head when looking at old circuits with PNP transistors as the +Ve supply can be seen as ground. Whit valves the grid leak biasing always makes me scratch my head, electrons leaking out providing a negative bias. 🙂 Hope you don't mind me dropping a sly hint for my electronics experimenters kit series. ;-)

[@GadgetReboot]

The more information people have access to, the better! everyone should be promoting all available helpful Content. I always avoid PNP circuits because I can’t get past the fact that electricity has to flow in the wrong direction to use them, defying the laws of gravity and everything else. The circuits would need to be put in enclosures to keep the electrons inside.

[@TheEmbeddedHobbyist]

@@GadgetReboot Well just to throw a spanner in the works, electrons flow from the -Ve to the +Ve. the arrows on diodes and transistor point in the direction of conventional current flow (holes) and ignore the electrons. Another thing to head around is electrons travel down a wire at the same speed or less than a🐌

[@RyanUptonInnovator]

Great work.

[@HazeAnderson]

Where did you get 0.65V for the BE junction at 4:53 ? Is that in the data sheet? Thanks for this video! 🙂👍 Math used to beat me up and take my lunch munies in high school 🤕

[@GadgetReboot]

it can be hard to find certain stuff in data sheets and then different data sheets between different manufacturers might imply different things or omit specs or only provide the spec for a very specific usage case like a specific collector current that’s not anywhere near what you want to use. Generally it’s accepted as between 0.6 and 0.7 V and most people just use 0.7 but I noticed at least one of mine in the transistor tester was measuring closer to 0.65 so I used that. it will change anyway based on temperature or current fluctuations so I think it all works out within a few percent for accuracy.

[@HazeAnderson]

@@GadgetReboot Thank you! 🙏Now then, where can I obtain a pack of those "professinal semiconductr" TO-92 packages? 😆

[@GadgetReboot]

I wish I could say RadioShack but now everything has to be shipped in