How Transistors Work - The Learning Circuit
Ғылым және технология
Rather than using a physical, mechanical switch, a transistor can act as an electronic switch, using signals to turn it on or off. Karen goes over what transistors are, how they work, and some different types of transistors: Bipololar junction transistors (BJT), NPN transistors, PNP transistors, and darlington transistors. Connect with Karen on element14: bit.ly/2EASjxT
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Previously, we’ve talked about how diodes work. Silicon diodes have a p-n junction. Bipolar junction transistors or BJTs are bipolar because they have two p-n junctions. BJTs are essentially two diodes in a single package. The two main types are NPN and PNP transistors. NPN transistors have two n-type regions on either side of one p-type region, while PNP transistors have two p-type regions, on either side of one n-type region. Bipolar transistors have 3 leads, one going to each region. Typically, the middle layer is the base. P-type in an NPN, and n-type in a PNP. One of the other layers form the emitter and the third, the collector. These are labelled B, E, and C. On the circuit symbol, the arrow is always on the emitter, so we can tell which lead is the emitter and which is the collector by seeing which one has the arrow. The NPN transistor symbol has an arrow on the emitter pointing out, while the PNP transistor symbol has an arrow on the emitter pointing in. Transistors act as an electronic switch, conducting current across the collector-emitter path when a voltage is applied to the base. The switch is off if there is no base voltage present. When base voltage is present, the switch is on. We know from our diodes lesson, that diodes require a forward voltage of 0.7V before they are turned "on" allowing current to flow. In a standard NPN transistor, when 0.7V is applied between the base and the emitter, the transistor “turns ON”, allowing current to flow from the collector to the emitter. With an NPN transistor, we normally bias the device so that the collector voltage is positive with respect to the emitter. The voltage across these two points is referred to as the Collector-Emitter Voltage or VCE. If you connect the base to be positive with respect to the emitter, the voltage is referred to as the Base-Emitter voltage, or VBE. For a PNP transistor, rather than needing a minimum of 0.7V on the base of the transistor, there needs to be a minimum difference of 0.7V between the VCE, collector-emitter voltage, and VBE, base-emitter voltage. If the circuit power supply is a 9V battery, the base-emitter voltage would need to be no more than 8.3V for the transistor to turn “on” and allow current to flow between the collector and emitter. If the base-emitter voltage is 8.6V, a difference of 0.4V, the transistor would be off and no current would flow. If the base-emitter voltage is 7V, the difference of 2V is greater than 0.7V so the transistor would be “on”, allowing current to flow between the emitter and collector.
Пікірлер: 857
This content has been recreated as an eBook for easy offline reference - part one is available now for free: bit.ly/3tpT0PS Also check out the Candy Thief Alarm project Karen created with her newfound transistors knowledge bit.ly/3jlR32f Or the conversation between Karen and James (aka thebaldengineer) about transistors bit.ly/36HoGXr
@AntHenson
2 жыл бұрын
Hey, your ebook link doesn't appear to be working :/
@omarpalislamovic7102
2 жыл бұрын
element14 presents, go to hell.
@darkhumorsecret
2 жыл бұрын
You literally taught me in 7 minutes what my instructor failed to do in an hour.
@johnskariah1233
Жыл бұрын
You too fast
This is an AWESOME lesson. You pulled back the veil that has shrouded this in mystery to me for years.
Great refresher. I used to dabble with semi conductors as a kid, but didn't really understand how they worked. This video brought it all back for me...thanks!
Excellent video. Easy to understand. Logically ordered. Very professional. Like listening to a talented engineering expert.
Thank you for this video. Well explained and easy to understand. You are the personal teacher of so many people that acess youtube. You give joy, and self fullfilment to so many people. I cherish you in my mind.
Without really knowing much of anything about electronics I could still get the idea of how this works. Fantastic....must resist temptation to binge watch entire series now....
I think this is the first time I've ever been able to wrap my head around this.
Thanks to your simple explanation i think i finally understand PNP transistors which seemed more complex than NPN :D
Thanks, this is the only video that makes it super simple to understand without the presenters stroking their ego by trying to sound smart by overcomplicating things.
I swear to god I just spent 15 minutes reading about how transistors work but 3 minutes into this video I feel a lot more enlightened. The article never even mentioned why it’s called a transistor.
@bradzimmerman306
3 жыл бұрын
Maybe check the first thing she says at the :25 mark
@entidade1000
3 жыл бұрын
@@bradzimmerman306 how does it feel to be stupid?
@bradzimmerman306
3 жыл бұрын
@@entidade1000 I don’t know. Tell me how you feel.
This is the most amazing explanation of transistors that I have ever run across! Thank you!
Comprehensive, easy to understand explanation. Thank you.
Thanks, professionally made and good for reviewing the fundamentals.
OMG, thank you Karen.....a lot easier to understand than some of the stuff I've read!
we owe everything to these transistors. I was working as a tube tech when these devices started to hit the market. like in all things the new replaces the old. as for npn and pnp it depends on the circuit I design. thus, a super stable low frequency tunable osc requires a small load transistor in a reverse polarity configuration.
In just 7 min you cleared every thing. Teaching is an art and that's true.
I am a new learner and found this video very useful and informative. The pace was perfect for me.
@hardwareng
6 күн бұрын
what is your progress at the moment??
You have the most perfect explanation about transistor using precise circuits
I've spent the last week trying to figure out transistors, reading a lot of material and this was one of the most helpful resources in understanding them. Thank you so much for sharing!
@oladayosulyman6885
2 жыл бұрын
Me too
@oladayosulyman6885
2 жыл бұрын
Expecially for the PNP
i finally felt i understood the transistor basics now. wow that took some years to grip but this video confirmed everything ive understood and by watching this i now got it, thanks
Thanks sister. U explained every thing in a very understandable manner.pl extend your lesson further for novice and other interested.
Thanks so much .. this is a great video to understanding npn and pnp transistors .. really thank you 😊
PNP = Points iN Permanently NPN = Never Points iN this may help with reading schematics.
@Limeayy
5 жыл бұрын
i remember this in class.
@rakshithakoriraj8469
5 жыл бұрын
wow.. really helpful
@wakefieldyorkshire
5 жыл бұрын
Excellent MNOMIC Andreas, if you have any more; indeed if anyone has any more, please leave us them in the comments. They are really helpful. Thanks, hats off to you and cheers.
@ariztech1058
5 жыл бұрын
Thanks Stevens
@user-wq1nm4lc7q
4 жыл бұрын
Andreas. Thank you. This was the question raised in the mind when i was listening the lecture. How to keep in memory the arrow direction.?..you answered. Thank you
very good and detailed explanations, cleared so many doubts which i had about transistors. thanks for making this video.
Well. This video was very helpful! I thought to turn on an NPN transistor, I just needed to have .6v sitting at the base. Knowledge gap. Didn't realize it needed to flow through b to e. Its working now! Thanks
With a non-science backgorund was struggling to get a minimum jibor-jabor explanation. Thank you so much
Thank you so much for this explanation, solved a problem after a month
Sincere effort to explain the smallest monster of the electronics. Also elaborate with equations. Have a nice day
Freaking awesome video, really dispels the difficulty of learning this stuff!
Incredibly clear explanation. Thank you.
BEST EXPLANATION..., I TRULY HOPE THIS CHANNEL CAN GIVE ME A BETTER UNDERSTANDING OF ELECTRONICS AND HOW THEY ALL WORK TOGETHER THANK YOU I WILL BE SUBSCRIBING !
Wow, this is amazing you deliver it in a unique and short way. Thank you, god bless you.
You 'v got me on the right way, of the transistor. Thank you very much Karin..aptly great channel.
Amazing presentation, deep but easy to learn.
Will we see transistors used in a circuit in a future episode? This information is great. I haven't had much exposure to working with transistors so I'll be sure to review this video back couple of times to make sure I understand everything.
@maker_karen1785
5 жыл бұрын
Yup! Coming up next Wednesday! I usually do episodes in pairs, first a lesson video, followed by a project using what was talked about in the lesson.
you are heaven sent.... Got D's and E's in physics bt now that i need PCB skills in real life you make it much much easier... thanks
Taking AC voltage and turning it into DC voltage. Glad I found this channel helps clear the fog from things learned long ago. Also after searching manually through your videos could not find an explanation on the theory covering transformers and rectifying diodes and proper capacitors.
@EJP286CRSKW
4 жыл бұрын
Rud Dog There is no turning AC into DC here.
it is a great Explanation. when somebody explainsa this way Electronic circuits become easier to understand. I'm a beginner. Thank you very much.
This video has taught me more than any other video. Thanks 😊
Darlingtons are an awesome solution for interfacing micros with stepper motors; done that a few times in the past.
Great Video Karen! Amazing explanation and easy to understand
Best explanation I've heard so far, thanks.
never seen such a well explained topic
I did mechanical and he did electrical. I got more interested in electronics and he helped me a bit until I couldn't catch up with him especially when he started designing power amplifiers using Darlingtons . Oh yes! I manually etched a working stereo 20x20W. That was in 1981 and now I can try catch up.
Great I have always wanted to learn about circuits. Thank you so much.
This lady is really cool, Im binge watching her tutorials. Excellent teacher !
Beautiful concise explanation!
Thank you for a very good lesson 👍🏾
Excellent explanation and very nice explanation. Thanks for the tutorial.
Keren, thanks! Looking forward for tge next.
great explanation!!! Thank you for sharing your knowledge!!!
explicit, well presented and made easy.
excellent teaching Karen...Thank you!!
Really good explanation. Thank you
I learned vacuum tubes first and some of the older books compare a tube to a transistor. So that made it easy for me to learn transistors.
@rty1955
3 жыл бұрын
Tubes were much nore forgiving. I began designing tube circuits and if you make a mistake like grounding a grid, the plate glows cherry red hahh With a transistor, it just gets damaged and the circuit fails to operate leaving you with "ok why isnt this working?" Of course working with non lethal voltages has its benifits hahah Once I was working on a T.V. and had my hands inside while adjusting the time and my knuckle came to close to the horizontal output tube playe cap. That Hurt a LOT!!! I once got belted with the anode wire for a b&w crt. my jand felt like it was in a. Vise and then got smacked witha hammer! Ouch!
@cat-lw6kq
3 жыл бұрын
@@rty1955 I've worked on both. Transistor sets you slip with you probe and short something and you blow out half the set.
@rty1955
3 жыл бұрын
@@cat-lw6kq haha true. Ya gotta be careful with all.esp. now with close tolerances. Gone are point to point wiring where U can push components out if the way to get to a test point
@cat-lw6kq
3 жыл бұрын
@@rty1955 those old tube sets could take a lot of abuse. My teacher would show us what would happen if parts of a tv failed by removing tubes in a working set. The set was powered on and he would pull tubes one at a time. Try doing that with a transistor set.
@rty1955
3 жыл бұрын
@@cat-lw6kq how very true. He must of had silicon hands! I recall working in a broadcast T.V. studio where 21" Conrac monitors hung from the lighting grid. They replaced the covers with a screen mesh to allow for airflow. When i took it down for repair, I put it on the bench and powered it on. I could have baked a cake in that thing!
Very nice video Lady. Please make more simple explanation videos about electronic. Thank you so much
Very helpful. Thank you. Hope for more vedio.
Thank you wonderful style in the explanation
nice informative video, the development always goes further, bipolar transistors were replaced by PMOS that were replaced by NMOS that were replaced by CMOS.
This is one of the top electronics channels out there
Hi, how are you. I am really flattered. You explained very nicely and impressively. I am 60 years old man with 42 yeas experience in technical work and I have many Invented designs and many mega projects but I am living in the environment Where is no support from the government for the real visionary people. Each day I am thinking that life is not to waste and each breath is to find out the Real good way to facilitate the whole mankind, but the people who has Power but they don't have a good visionary mind. If I were sponsored by the hogher level authority, I am 100% sure that My only One development program can bring wealth to the whole world but, I am helpless to show because there is no support and sponsor for the true visionary mind people. I am very much impressed from your ability to explain and the real Seekers. Love you so very much, ❤ may God bless you.❤❤❤
Thank you for a very interesting video.
"Thank You", thank you very much 😁 Your presentation/video was REALLY good 😎
Actually useful information for me, thanks.
Now that's an effective way to teach, great stuff, thankyou
You simply the best.easy understanding how actually transistor works.
one of the best explained ....thank you so much...
WoW! great explanation, tks very much!
If you discuss Darlington Pairs, it would also be useful to discuss Szicklai Pairs. I understand that the Darlington Pair discussion was a teaser. Therefore, I suggest a follow up in depth discussion of Darlington and Szicklai Pairs for a future video.
Excellent description & thanks
Just a small correction. It is called bipolar because it depends on both electrons and holes! not because it has 2 pn junctions.
Well explained, great work
Great video. Really enjoying these. One small nitpick - at 2:39 I believe you really meant to say "the small signal current flows from the base to the emitter" not "from the base to the collector". The diagram however is correct.
@mohamedsalama1857
4 жыл бұрын
Great
@TortureBot
2 жыл бұрын
I just noticed that. I was like, "Am I misunderstanding??" Guess she just misspoke.
Excellent explanation
These are awsome thanks for them it is nice to have a greater understanding of the components i use.
@dwightbacchus8002
5 жыл бұрын
O t
Awesome video.. amazingly useful..! Million thanks for sharing..
Very good teaching, thank you.
Please also explains about voltage amplification & modulation by using PNP & NPN Transistors
This is DEFINITELY and EASILY the BEST explanation I've ever seen on this target level. Using those two voltage sources in the explanatory schematic was genius!!! And the explanation on vBE and vCE was something that often doesn't even get talked about in other vids.
@cat-lw6kq
5 жыл бұрын
except the explanation about the PNP is not correct. The only difference is the battery in the diagram it would be flipped around so the (-) goes to the base. PNP and NPN both require .7v bias.
@lucysluckyday
5 жыл бұрын
@@cat-lw6kq It looks correct to me. If using the classic positive current model then the current flowing from positive terminal on right flows into the emitter and (mostly) out through the collector, where the base signaling current would need to have a voltage of 8.3V or less. In other words, if you think in digital terms (rather than analog) she is trying to show that a logic 0 applied to the base switches the PNP BJT on to allow the primary current to flow through from E to C.
@cat-lw6kq
5 жыл бұрын
Suggest you buy one of those cheap transistor testers off ebay. for test some transistors with it, it will show the bias voltage and the gain. The tester has a digital readout, it shows bias (B-E) voltage and gain. You will see a bias of about .7v if the transitor is good.
@EJP286CRSKW
4 жыл бұрын
It isn't the best. Half of it is totally incorrect. Look harder. Try the PNP circuit shown and measure for yourself. The voltages are not as described.
thank you ! you make everything is understandable
Thank you very much i really like your videos very educating keep up the good work
amazing, none of KZreadr can explained except YOU, thanks
I wish you were my university professor, because you just explained something better in 7 minutes than they did in 7 hours' worth of lectures.
You explain very well, congratulations Teacher. I'm french student and i manage in english. Can i have somes transistor's applications ? Thank you for all and have a nice day...👍
Great refresher, thanks.
Excellent information, many many thanks, I have learnt alot.
Excelente información. Muchas Gracias.!
For basic knowledge is a very good learn Thanks
Great!! You did it again. You're the best!
Very nice 👌 thanks for educating the world 🙏
Thanks for sharing this...I learned a lot
Hi, I'm Tareq from Bangladesh. Thanks for your nice concept.
Wow what a great lesson. Thanks a million
thank you for your knowledge
very helpful I would have to have practical applyications before I can get it in my head Thank you!
good one...simple & effective
amazing explaination! this is pretty much the only video I understood. very well done! (I subbed :))
Excellent video but a bit hard to follow on its own, without looking at the "previous video" you refer to. I'd suggest providing a link to it for ease of use. Cheers!
Hello, first time I find a girl who works in the field of electronics, I am happy For watching your wonderful channel, greetings to you, my dear sister Very nice 👍👍
Thank you Karen. Enlightens .