NPN vs. PNP Transistors as Common-Emitter Switches
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- Опубликовано: 26 сен 2024
- NPN and PNP transistors are two complementary types of bipolar junction transistors (BJTs). They both work the same way: when current flows thru the Base-Emmitter junction, the transistor "turns on", and creates a current path through the Collector-Emmitter junction. The amount of current that will flow through the C-E junction (our "Load" current), is determined by the amount of current flowing thru the B-E junction (our "Control" current). (The C-E current is typically larger than the B-E current, and it's equal to the B-E current multiplied by some value, called "hFE" or "common emitter current gain".)
The only significant difference between an NPN and a PNP transistor is that to turn on an NPN transistor, current flows IN to the Base and OUT of the Emitter; we accomplish this by applying a positive voltage to the Base relative to the Emitter. To turn on a PNP transistor, current must flow IN to the Emitter and OUT of the Base (the opposite direction of NPN), and to accomplish this we a apply a negative voltage to the Base RELATIVE TO the Emitter. That is why you see things like "-5V" in a datasheet for PNP. Usually the Emitter is "common" and thus a voltage reference for the Base.
Bipolar transistors are often used as simple switches in a "common emitter" configuration. For NPN transistors, we tie the Emitter to ground and turn the transistor on by applying a voltage to the base that is higher than ground; the Collector provides a "switched ground" output (either "open" or tied to ground).
For PNP transistors, we tie the Emitter to our positive power supply rail, and turn the transistor on by applying a voltage to the base that is lower than the positive power supply rail; the Collector provides a "switched positive" output (either open or tied to the positive power supply rail).
One of the best, simplest, and most straight-to-the-point demonstrations I've seen. Obviously excluding the backwards battery
Thanks!
This really helped me understand transistors better than any other videos I have seen. When the teacher is good, also difficult things are easier to grasp.
Except for the battery symbol being flipped, the explanation is Very clear and easily understood.
Thanks!
That was the best description of NPN vs PNP I have seen
+Mike Catlapp Awesome, glad it could be of help!
Not sure if it was mentioned, that PNP transistors are commonly used in audio power amplifiers as a complementary pair on the output end, working in a push/pull configuration of the signal.
Simple, to the point and not losing yourself in details. Good job.
Nobody but you, made it easy to understand, I could never understand, the shunt
effect. good video, I hope you have one on Mosfets. Thanks.
MrMac5150 Thanks! Yes, I will be posting more videos on mosfets and other components.
Kevin Patterson
You have got my attention on your channel,
it is excellent.
Glad to have you. Thanks!
I don't want to seem negative, but I am positive that your battery symbol is reversed.
+madamerotten yup... a sketch drawn in haste and then turned around... I will apparently never live this one down. :(
3 GUARD
Doe!
I actually disagree.. since power seems to actually work from neg to positive. And not from pos to neg. I think it is more accurate this way.
he has the Positive terminal of the battery connected to the ground symbol, and has labelled it negative, while the negative terminal of the battery is labelled positive.
Watched ten transistor videos before this one. Yours was the best. Excellent job!
+Mark Warbington Thanks!
Agree
Yup I second that.
I agree too
Me fourth
Thank you Kevin! This is the most concise yet probably the best explanation I've seen about the topic.
Finally! NPN transistors and PNP explained, in a COMPREHENSIBLE manner, for complete NOOBS like me. Been looking all over the web and all I came across was a bunch of FAST talking know-it-alls preaching to the already converted. Kudos and THANK YOU good sir, for this great video. Cheers!
You're welcome! Glad it was helpful.
As an Electronics technician for the last 25 years, my job primarily has been to troubleshoot why something isn’t working, having a basic understanding of electronics principles and experience with tons of failure scenarios has served me well. Scrolling through the videos on here today I found yours to be the only one that brilliantly and simply explained transistors, I loved the imaginary jumper explanation of how the transistor works as a switch. When troubleshooting any electronic device the first rule is simplicity! Example - if your receivers FM band isn’t working doubtful you’ll find the problem in the amp section. Well done sir!
Five vids in and you are the one that nailed it. One guy even showed how to wire an NPN when he was in fact using a PNP......confusing as hell. I was following along on my breadboard.
Nice video, clear explanation. Keep it up.
Thanks! Glad it was helpful!
agreed! video eeds more votes!!
Theres 80% of idiots who pretend to know and understand and 15% of those who intentionally upload the Internet with false information and knowledge.
Best transistor explanation ive seen thus far!
Thanks!
Hands on one of the best explanations available on transistors! Keep up the good work!
What really blew my mind about this video is that I never thought of transistors as actually being two different circuits. I think I understand them far better than ever before now!
Glad it was helpful!
Years I have tried to grasp this. Wow... thanks.
Finally. Not even nine minutes long and I can actually get it . Why can't they all be this simple? I was seriously becoming convinced that an easy explanation was not out there. Subscribed.
Thanks! Glad it was helpful!
This was THE best explanation of the npn/pnp transistors! Subscribed! :D
Thanks!
it is so sad I am paying for university but have to go to youtube to get a professor who doesn't just spew formulae and actually explains the concepts.
Thanks for the concise explanation.
You're welcome! Hopefully things will become clearer as you get a handle on the basics. Good luck!
Perfectly explained the difference between PNP and NPN !! I have searched more than 10 videos and no one is better than this one !!! Thank you!
Awesome, thanks!
This is the best and clearest description of the switching function of transistors I have seen, very well explained, thanks.
Awesome, glad you found it helpful!
I swear, you have explained the transistor basics more and way better than when I took it back in school.
Even with the battery symbol slip (didn't notice till I read some comments) the walk through of the concept was extremely useful and well explained. Thank you very much for this video.
Thank you, thank you. Finally, an explanation on how to use transistors and not how they work internally.
+Nick James Thanks, and you're welcome!
The very best explanation and video I have ever seen on transistors. They have always been confusing to me. I never thought anyone could explain these silly little devices in a clear and simple way. YOU DID AND YOU NAILED IT.
best explanation yet. Now I start to understand the basis of transistor use in amplification.
The clearest explanation found...thanks for sharing
dude, I went through at least 50 vids trying to understand, I got a basic idea, but you my friend, youuuu, your voice is clear, its smooth and easy to.listen to, its sound is just right, your pauses are perfect while explaining, the mellowness helps, and within all that the overall explanation of the how hard it is for us noobs, you make it sooooo much easier my friend, you get unlimited lifetime likes and promoted to my diy buddies thank you GB..
having said that I'm still learning on how to.make it work with my project, I'm trying to make a solar lamp, I'm using a 3.7v lithium ion battery , 2400mah. I have my light dependant resistor which I think its around 15ohms, and my load (LEDs) will vary, my problem is to find an easy formula to calculate what resistor will I need to work with each individual led or small 6v hylogen lamps, if you can point me in the right direction I would appreciate it
Of all videos I've watched about transistors, your video made understand it better. Thank You
I have watched so many videos, I name it BY-FAR THE BEST.
Best video. After 2 years, I finally understand the difference
+Jason Green Awesome, thanks!
+Jason Green .you are lucky. it takes 4yrs for me.
Thanks Kevin, I've see through many videos about the transistor, their explanation are complicated but you're making it easier for people to understand
+Forever Joy Thanks!
This is the best explanation of PNP vs NPN transistors I have come across.
Finally an easy to understand explanation
Excellent. Clear. Understandable. No frills. Great teacher.
I subscribe to this channel , because this man has a unique gift.
He explains things in the most easiest way to understand, in the most easiest conotation, in the most simple way.
He does it slowly and explicitly.
This is the best teacher i have seen on youtube.
The best explanation of these transistors that I've EVER seen! Keep up your good work.
Thanks!
Ii love your elegant and simple illustrations and explanations. This was very well done.
Thanks!
thanks kevin petterson this is the best tutorial i have seen yet
Aashu Malik You're welcome!
Great video on the basics of transistors clearly goes over the current flow and the function of transistors theory.
Good video my good sir. The inverted symbol of your power source is in fact inverted but you are aware of it.
Thank you for your video
+MrRanmaedu Thanks for the kind remarks.
Amazing! As an outsider, I learned a lot from this video!!
Awesome!
As a welder, I learned long ago that DC voltage flows from negative to positive. You can weld with the electrode set up at either polarity, but electrode negative results in a deeper puddle ( more heat into the work piece ), and cooler running feed wire. Reverse the set up and you have just the opposite outcome. Just saying. Your presentation is very well done and thank you for sharing.
Yes, conventional current flow (as used on schematics), is the opposite of electron current flow. Still no excuse for drawing the battery symbol upside down! :( Thanks for the kind remarks!
Perfect video mate. Still helping people in 2021. Thanks
Simplest and best video I found. Great explanation. Many thanks.
You're welcome!
FINALLY! A video I can understand and actually learn how transistors work! Thanks man :)
I watched this many time before I finally got it and even though I'm still not sure. However, I feel I have enough of a grasp to implement it in my circuits. Thank you!
+PS Awesome, keep at it. I started learning electronics when I was just a kid, and it's amazing when I look back and realize how little I actually understood and all the misconceptions I had. However, perseverance and study will get you there. Sometimes experimentation is the fastest way to learn. :)
I also watched eleven or twenty transistors videos before this one. Yours was the best. Excellent job!
I was struggling to understand the difference between npn & pnp.Your last statement clarified everything for me : control signal has to be lower than 5v to turn on a pnp and control signal has to be higher than 0v to turn on npn. Thank you!
Awesome video super understandable LOL. Finally i understand how transistors work and the difference between PNP and NPN. Thank you very much kevin.
You're welcome!
The Best Explanation Of NPN/PNP If Seen. Just the right type of Vid for a beginner like me
Glad you found it useful!
best explanation I've seen anywhere, thanks so much
+Cutty Flam You're welcome!
Excellent tutorial. The BJT is a "current multiplier". The PNP emitter faces power, the NPN emitter faces ground.
You made it simple for me , i've watched many videos about transistors and everybody is trying to be so coplicated ( you see coplicated is more kickass than simple).
For a first time i can make my Simple circut of a Transistor. So i say Thank you Sir. -from Tanzania East Africa
Simply superb.very easy to understood. thanks a lot.
You're welcome!
This is best explanation by far thank you. Was so confused on how to set it up.
Thank you, good sir, transistor basics are a lot clearer to me now! Keep up the good work! I would absolutely love to hear more of your own spin on electronic tutorials in the future!
For instance; radio frequency/communication systems explained easy.
+qdnguyenbp I will certainly be making more videos as I have the time. Thanks for the encouragement!
I've been watching lots of video about transistor. But yours is my favorite. It answers my questions.
OK, I had my doubts when it started going by the battery symbol, but I actually watched out of curiosity and this is really good!
Thanks for the great video. Finally learnt something useful about PNP transistors! Cheers!
You're welcome!
Just awesome video! cheers from Brazil!
+Henrique Marques Fernandes Glad you liked it. Cheers!
Thank you for this video, i was having a very hard time understanding the difference between the two with what i read on google, watched this video and instantly understood it.
One way of memorizing which symbol is NPN is that the arrow is; Not Pointing iN
And my way to memorize: nPn needs Positive on its base, pNp needs Negative. And the arrow points the direction of current. What's so hard on that?
The 'P' is in the middle....and rhymes with Pee
Nice explanation. Easy to understand and no confusion.
Your lesson was well done and easily understood.
You are the best man! So simple you give us light with how it works! So many videos here in youtube for this topic, but this is the best one!
This is the first time I understood. Thanx
You're welcome!
Pity you never made more videos. You have such a way at explaining these concepts.
FINALLY a good explanation of transistors!!!
Joshua Foster Thanks!
finally i understand how transistor work as a switch i watched many videos but yours is the best
Best explanation ever. Finally i get the idea about PNP trans. Too bad you dont have hundreds videos regarding electronics
This the best tutorial so far.
Thanks!
Thank you! This is by far the best explanation.
You're welcome!
Struggling to learn this stuff, I took a screen cap at 7:39 and printed it off. This helps a lot thank you!
brandon day You're welcome! Keep studying, the learning pays off!
nice explanation sir . you made it really easy to understand .
hats off .
Thank you!
Never seen such a clear explanation. Excellent! It might be also useful to show some practical examples, i.e. say we have 5V battery, 2K base resistor, which provides xx mA to the base and that results in yy mA current through the LED.
+1yyymmmddd Thanks for the kudos. I do have another video that shows the circuit in action (in a simulator), and I think it shows some numbers too. Check it out: ruclips.net/video/InAlz5n7TbU/видео.html
Why don't you come to my university as my lecturer? Nice presentation for npn and pnp transistor!! I could save a few weeks if I find this video early!
Best explanation.Simple and easy to understand.Thanks :)
+atelesia Thanks!
Thank you Mr. Kevin Patterson ,Nice video & Explanation.
Thanks!
In the U.K. especially in industry, PNP based sensors are a lot more common. That’s because you’re switching the positive terminal of the load. It makes much more logical sense to use these transistors for references as it’s more practical. As most people will treat an output from a sensor as a positive terminal and look for a negative reference.
Best explanation I heard !! Thanks for sharing!!
Very nice job explaining the difference!!
Best explanation ever, and I have been through bunch of tutorials on youtube. Thank you.
Great! exactly that explanation i was looking for! Thank you.
+michi tuurbentaler You're welcome!
Thumbs up for hand sharpened pencil and nice drawings. And great explanation of NPN and PNP.
Thanks for the class
What a fantastic video. Thank you.
You're welcome!
Yes BRILLIANTLY explained!
Thank you man! Great Video!
Thanks for the kind words. You're welcome!
Great explaination very clear and pitched just right for someone, like me, fairly new to electronics
Nice explaination bro.. .😀 finally understanding how transistor works thnx
Glad it was helpful!
Very well explained, one of the best on RUclips. Thank you
I'm just learning, and that was a great help!cbr
Great!
Thank you for the lesson 😄👍🏿
Very helpfull thank you very much. Other videos on the internet are still complicated and miss this point of view.
You explained the subject perfect, God bless you and your family, you"l e I y daily prayer
very good explanation...long time ago he...but still helping...thank you Kevin.
great explanation, please keep it on as habit and thank you so much indeed.
Thanks!
thank you you explained this very easily than some others
Thanks finally away for me to understand!!!!!
You're welcome!