This is the best series on transistor circuits I have seen. You have made a really challenging topic very easy to digest. I also appreciate that you were able to connect the dots to applications of these circuits. It really helps to reinforce why particular parameters we are solving for are important. Thank you!
Your transistor lectures are amazing and so helpful. You really know what you are talking about and explain it so well. Thanks for making these videos publicly available.
Sir, I did not learn a bit. I have in fact learned A LOT. Thank you so much for this explanation. My finals are in a few days, and you have accelerated my learning.
Well done! Especially the part around 14:00 where you show extremes (cutoff, saturation) then example circuit, then show those locations on the characteristic curves.
Bleedy hail! I finally understand what the heck 'load line' is and how I can do all those 'tests' and do the graph! I watched loads of RUclipsrs talking about finding the Q point, BJT as switch must be in saturation region, BJT as amplifier must be in active region, and whatnot. But generally no one explains the 'how'.
Thank you very much for this. I am at Red River College here in Winnipeg studying EET during COVID. You sure make online learning very effective. As a side note it would be awesome if you actually did some practical demonstrations. Proving theory with practice, demonstrating this with breadboard built circuits and DMM. Thank you again
Thank you so much David Williams! I learned a lot! At BCIT for Robotics with Maurice LeNoble, Im glad you made these videos these were amazing study aids!
I'm an electronics hobbyist, and long ago took Manpower training to repair VCRs and other stuff. We learned basic transistor circuits, but I've been trying to learn the transistor essentials. While many people have a little here and a little there. Your videos seem to be right on the mark for what I want. !51K views is good but not great, but ungrateful people have not been clicking their appreciation. I'll dig out the spanking paddle and see if i can improve that!
Another way to put that is using KVL on the collector-emitter part of the circuit: VCC - ICRC - VCE = 0. In saturation VCE is about 0, so VCC = ICRC -> IC is maximized at IC = VCC/RC
When Ib increases, it causes Ic to increase as well. Ic is flowing through resistor Ic and when the voltage drop across Rc (Ic*Rc) is equal to the supply voltage Vcc, Vce = 0V by Kirchoff's Voltage Law.
It is true that Ib determines Ic regardless of Rc, but only up to a point. Kirchoff's Voltage Law (KVL) overrules Ic = (beta)Ib. This applies specifically when you push the BJT into saturation - in saturation Ic less than (beta)Ib. For example, if you have a circuit with RC, but no RE and you assume that VCE(sat) is 0V, then ICRC can be no bigger than VCC.
Hello!! :) Best series on transistors!! Thank you very much! :) A minor question: do the videos in the BJT playlist have a particular order? Is the correct ordering as they are shown in the playlist? Or do I need to watch the videos in another order?
You missed some important points. One: The Vce is held constant when doing the curves. Two: the beta will not be constant as the Ic is varied. Three: the curves are not flat but rather have a slope that converges on the V-axis at -Va ( Va is the Early Voltage, an important factor in determining the output conductance of the transistor). And Four: The Vbe is not a constant 0.7 volts but increases as the Ib is increased. If you look at the Diode eqn, you see forward conduction begins to become significant at about 0.5 volts and is quite large by the time you get to 0.7V.
in the common grounded emitter circuit figuration as in this video, can we say that Vce is biased by Vcc? In the set of characteristic curves, Ic is actually small in the saturation region before being amplified in the active region, but one might say this is contradictory to Ic being maximally saturated as it flows through Rc toward a very small Vce. Is this because as we trace through each 1 of the characteristic curves starting from a small Vce value, Vcc is also small before increasing along with an increasing Vce through the curve into the active region, so that Ic is also small as well before increasing as we go into the active region, given a fixed Rc?
In relation to your extreme case 1: what if I have 0 potential at B but negative potential at E. Will there be a current in that case? Which means in npn transistor, From p to n, potential is 0 to negative.
Just to be clear: The operating point is not an intrinsic independent quality of the transistor, but depends, in part , on the circuit arrangement (resisters etc) the transistor finds itself in. Is this correct?
It does not mentions why does the collector current is so dependent on base current? Shouldn't it only depend on whether the transistor is switched on or off? and then Ic should max out to any value till the junction catches on fire?
What is the relationship between the collector/emmitter voltage an Ib. Its a bit confusing. Does increasing Vce increase Ib ? I thought at stauration that Vce was 0.2V . It does not appear this way for all the I(b) curves above. can you clarify. Thanks Mike
I hope you could explain how does the curves plotted. What equation can we use to plot that curve? Like for IB=40uA, how do you get the points for that?
It is experimental data. You have one power supply for the base, one for the collector. You vary the supplies and get the readings. Unless you have an intern or student available for boring tasks, you use a computer to set various base voltages, and then scan the collector voltage, keeping track of Ic and Vce. The the highly paid engineer loads the data into Excel and generates a graph :-)
This is the best series on transistor circuits I have seen. You have made a really challenging topic very easy to digest.
I also appreciate that you were able to connect the dots to applications of these circuits. It really helps to reinforce why particular parameters we are solving for are important.
Thank you!
Wow, what a kind and thoughtful comment. Thank you.
Your transistor lectures are amazing and so helpful. You really know what you are talking about and explain it so well. Thanks for making these videos publicly available.
NOW i understand the dc load line. Second movie i saw made by you, clear and understandable for a (starting) hobbyist like me. Thankx!!
Glad I could help!
I can't believe this video is 8 years ago! Nice video, I like how you explain things.
Sir, I did not learn a bit. I have in fact learned A LOT. Thank you so much for this explanation. My finals are in a few days, and you have accelerated my learning.
Definitely the best on youtube! I wish more topics of analog electronics would be so clearly explained by you! Well done
Well done! Especially the part around 14:00 where you show extremes (cutoff, saturation) then example circuit, then show those locations on the characteristic curves.
Bleedy hail! I finally understand what the heck 'load line' is and how I can do all those 'tests' and do the graph!
I watched loads of RUclipsrs talking about finding the Q point, BJT as switch must be in saturation region, BJT as amplifier must be in active region, and whatnot. But generally no one explains the 'how'.
What an amazing tutorial explained very clear and made easy to understand, well done.
I've been searching for years for something like this
Thank you very much for this. I am at Red River College here in Winnipeg studying EET during COVID. You sure make online learning very effective. As a side note it would be awesome if you actually did some practical demonstrations. Proving theory with practice, demonstrating this with breadboard built circuits and DMM.
Thank you again
Thank you so much David Williams! I learned a lot! At BCIT for Robotics with Maurice LeNoble, Im glad you made these videos these were amazing study aids!
Wow, professional teaching!
I'm an electronics hobbyist, and long ago took Manpower training to repair VCRs and other stuff. We learned basic transistor circuits, but I've been trying to learn the transistor essentials. While many people have a little here and a little there. Your videos seem to be right on the mark for what I want. !51K views is good but not great, but ungrateful people have not been clicking their appreciation. I'll dig out the spanking paddle and see if i can improve that!
this is a great BJT example and a wonderful LTspice training project... thanks...:)
Another way to put that is using KVL on the collector-emitter part of the circuit: VCC - ICRC - VCE = 0. In saturation VCE is about 0, so VCC = ICRC -> IC is maximized at IC = VCC/RC
I remember a bit I studied the formulas but that was a long time ago I need to refresh thank you for this videos :)
Thank you so much! Very wonderfully explained.
You're very welcome!
When Ib increases, it causes Ic to increase as well. Ic is flowing through resistor Ic and when the voltage drop across Rc (Ic*Rc) is equal to the supply voltage Vcc, Vce = 0V by Kirchoff's Voltage Law.
Nice tutorial. Perfect for explaining how to complete my electronics lab THANKS!
You're so sweet 😍
It is true that Ib determines Ic regardless of Rc, but only up to a point. Kirchoff's Voltage Law (KVL) overrules Ic = (beta)Ib. This applies specifically when you push the BJT into saturation - in saturation Ic less than (beta)Ib. For example, if you have a circuit with RC, but no RE and you assume that VCE(sat) is 0V, then ICRC can be no bigger than VCC.
thanks for posting this video.
best explained David Williams .
Thanks alot .
Excellent explanation
best explantation so far, keep it up!
Hello!! :) Best series on transistors!! Thank you very much! :) A minor question: do the videos in the BJT playlist have a particular order? Is the correct ordering as they are shown in the playlist? Or do I need to watch the videos in another order?
It would be nice to have serial numbers also mentioned along with titles to correlate the videos.
you made my day thanks a lot
The Q point is where the load line intersects the base current of interest.
great video, thanks
Nice job. Thanks
Great, clear explanation! Thanks!
thanks a lot bro..really u made thing much more easier
You missed some important points. One: The Vce is held constant when doing the curves. Two: the beta will not be constant as the Ic is varied. Three: the curves are not flat but rather have a slope that converges on the V-axis at -Va ( Va is the Early Voltage, an important factor in determining the output conductance of the transistor). And Four: The Vbe is not a constant 0.7 volts but increases as the Ib is increased. If you look at the Diode eqn, you see forward conduction begins to become significant at about 0.5 volts and is quite large by the time you get to 0.7V.
in the common grounded emitter circuit figuration as in this video, can we say that Vce is biased by Vcc? In the set of characteristic curves, Ic is actually small in the saturation region before being amplified in the active region, but one might say this is contradictory to Ic being maximally saturated as it flows through Rc toward a very small Vce. Is this because as we trace through each 1 of the characteristic curves starting from a small Vce value, Vcc is also small before increasing along with an increasing Vce through the curve into the active region, so that Ic is also small as well before increasing as we go into the active region, given a fixed Rc?
Excellent lovely presentation
Wonderful!
Excellent videos, is there any chance you could do a video on the Common Base Amplifier?
Thank you so much. 👌
In relation to your extreme case 1: what if I have 0 potential at B but negative potential at E. Will there be a current in that case? Which means in npn transistor, From p to n, potential is 0 to negative.
Good video.
5:48 what is the function that describe those curves??? :(
Well explained
Just to be clear: The operating point is not an intrinsic independent quality of the transistor, but depends, in part , on the circuit arrangement (resisters etc) the transistor finds itself in. Is this correct?
That is correct. The operating point depends on both the transistor characteristics AND the circuit that it is in
It does not mentions why does the collector current is so dependent on base current? Shouldn't it only depend on whether the transistor is switched on or off? and then Ic should max out to any value till the junction catches on fire?
thanks for the help man
Trying to figure out why the Ic vs Vce curve peaks out. Is due to the physics of the transistor?
Excellent clarifications Sir Williams! Again... more (i^2)R
What is the relationship between the collector/emmitter voltage an Ib. Its a bit confusing. Does increasing Vce increase Ib ? I thought at stauration that Vce was 0.2V . It does not appear this way for all the I(b) curves above. can you clarify. Thanks Mike
I hope you could explain how does the curves plotted. What equation can we use to plot that curve? Like for IB=40uA, how do you get the points for that?
It is experimental data. You have one power supply for the base, one for the collector. You vary the supplies and get the readings. Unless you have an intern or student available for boring tasks, you use a computer to set various base voltages, and then scan the collector voltage, keeping track of Ic and Vce. The the highly paid engineer loads the data into Excel and generates a graph :-)
Why Ic starts to become flat after a certain Vec for a certain Ib? Thanks!
same prob here
Because ideally Ic depends on Ib for a transistor and not Vcc.
Ic = beta * Ib
Since Ib is kept constant, Ic will also remain constant
Can you determine where is the Quiescent point ?
Thank you : You Helped me a Lot ---
I m watching this video after 8 years
Good thing semiconductor physics hasn't changed in that time ;-)
Love u man
Thanks a lot for real
good stuff
the x-axis was set to 12 because of VCC being 12v. right ?
correct
there is no details in your explanations :(
Like how could the VCE = 0 when IB increases ????? what relation is there?
thank you very much !
(y)
wonderful
sweet jesus. good video
Salut to this explain me like im 5 legend of electronics
dude u r amazing
:P
ohhh . thanks dude
The best
dude ,, I just want to thaank youuuuuuuuuuuu :D (Y)
such a nice questioning by the viwers .but .....
thanks, bruh
Saturation is not Vce=0 it's Vce0.4V for it to work. This guy is neglecting way too much.
danger