0:00 Intro 1:07 Comment about Diode polarity from Part 1 - Cathode/Anode/ + & - 4:23 Adding a third element to the P-N junction of the diode- in theory 4:50 Enter the transistor: The NPN junctions 5:36 How a transistor works - the water pipe analogy 7:27 PNP junction / PNP transistor - almost the same with opposite polarity 8:30 The "diode model" of an NPN transistor (the PNP would have the diodes reversed) 10:00 Comparing NPN "diode model" to a real NPN transistor 11:00 Using the multimeter in diode check mode to identify base-emitter-collector 12:21 Using a tester to measure hFE, Ic, & Vbe 13:22 Using a test circuit to understand these measurements 27:57 Looking at the transistor datasheet 29:15 Looking at forward and reverse breakdown voltages - and exceeding them 40:12 Discussing the results of the tests 45:08 Looking at a schematic to see how the transistor can fail 50:56 Looking at transistor emitter-base forward vs reverse voltage behavior 52:26 How current affects reverse breakdown voltage 54:09 Cutoff current 55:36 hFE (A.K.A. "gain" or "ß") - A moving target! 1:00:16 Vbe 1:00:59 Matching transistors - some comments 1:02:56 fT or gain bandwidth product, better known as transition frequency 1:08:36 Output capacitance and Miller effect (They are not the same!) 1:09:36 Noise level 1:10:29 Looking at some of the graphs and some final information
I look at the diode polarity in the circuit, a totally different way. In your example, you are not connecting the cathode to a positive voltage. The positive voltage is established by virtue of the way the diode is connected. It is only conducting through the positive half of the AC since wave. There is both positive and negative on the transformer side of the diode no matter what direction it is connected in the circuit.
Thanks for the shout out to the shut-in tinkerer community. Don't underestimate how many of us are here. And, not only for the electronics education, but for the content of your character that is so uplifting. For my purposes, your channel is the best on RUclips. And, I am not even a stereo guy... just general electronics. Best teacher, best content, best atmosphere. Thank you!
RIP, little transistor, happily your life was not in vain. I learned so much about these mysterious components that have been a real blank page for me, thanks so much, Tony.
Xraytonyb, I could not help, but notice the black "NICE-POWER" branded power supply you have on your bench. I bought that same model power supply a few months ago, as well. Nice to see someone else thought it's a good one to have on the bench, with volts, amps and wattage read outs. I like the wattage read out feature. Keep up the good work on the instructional videos.
Thank you for making those videos. Even as a master electrician I did not know much of this stuff! I am learning a ton from this channel for which I am very grateful. Please consider making a playlist with the basic theory videos and servicing 101 to make it easier for newcomers to your channel to find them.
Tony: I got a lot out of this video, as it helped me de-mystify much of the information found on a typical data sheet. I can sympathize with those who found the presentation frustrating; as you really ‘bit off more than you could chew’ through in a relatively short video. I have tried teaching the same topic with much less understanding than you to a class of mostly young men. Strangely, the teaching tool that I took away was your destructive testing. I think that such a demonstration would really get my students attention, and they might learn something. They manage to destroy them anyway, even when they’re not trying to (although sometimes they are). I can certainly understand how the video ‘took a lot out of you,’ and you are a very good man for making the ‘Herculean’ effort to produce it in the first place. The topics you covered probably need to be broken down even further, and by the time you’re done you would have built an entire basic course in electronics over a range of twenty or so videos: which is not your main focus. It is my opinion that knowledge of basic electronics is revealed only to those who are both highly motivated and fairly intelligent with the curiosity and persistence to see it through to the end. You can ‘cast your bread upon the waters,’ but not everyone will be nourished thereby.
thank you for taking time to set all this up for teaching purposes.. really helped me wrap my head around a lot of this. Might have to rewatch even later but thankful to have this info. you are a really good teacher. !
Bipolar Junction Transistors, are current driven. The Base Emitter juction, is the diode part of the transistor. This produces the forward current, which allows the Collector to produce the amplified current, to drive the circuit!
Hello Tony , thank you for sharing ................I have some old (metal body) diodes where the cathode is indeed labeld with a +..... can be confusing when you don't know it !
Tony, Tangentially related comment: I have the same backlight tester, and the readability is indeed terrible. I had some improvement bay simply using a red marker to color some transparent tape, and covered the display with that. It does reduce the visibility of the non-illuminated segments, and enhances the visibility of the lighted ones. It would have been so simple - and inexpensive for the mfr to do this. I don’t think I’ll ever be able to fathom the logic processes used by Chinese bean counters.
I was interested in seeing how you would describe the operation of these devices. The workings of a vacuum tube are quite intuitive and easy to explain. Not so with semiconductors. The explanations are necessarily abstract and can be difficult to wrap your head around so kudos for this video. The only criticism I might make is that in your water analogy, you implied that instead of turning the transistor on, the base current chokes off the current. That is how a FET operates. Incidentally, I wasn't sure you had the cathode/anode designations on the diode correct until I realized that in your diagram, the diode is reverse biased. The way I remember it is the cathode is the negative end of the diode and the anode is the positive end when the diode is forward biased (conducting).
The spec sheet for the transistor indicates that the breakdown voltage is listed under the heading “min”. But your explanation is that it is a maximum voltage that should not be exceeded, which makes perfect sense. Can you explain why the confusion? Thanks for all you do to educate us.
If you test a lot of this transistors you will find out, that not all of them will start to break down at 120V, but you will get a range of values of breakdown voltages. The manufacturer usually does the same and adds a saftey margin. The value which comes in the datasheet is the minimum of the spread of voltages (+ margin), therefore it is in the min section. Take also care that this value is only valid at 25°C ambient temperature! But for your design this is the maximum value which should appear worst case. Usually you should stay well below.
Thanks, Tony. Herculean effort for.something that most would find, well, boring. Thank goodness I'm not one of those. I watched all the way through since it is really interesting. Hey, do you know why it's called a transistor? Its a good story as well.
"Transistor" is short for "transfer resistance". It got that name because it is a current dual of a vacuum tube which is characterized by a "mutual conductance".
Regarding the diode "see that stripe, that's going to be your cathode, even though you connect the positive to it" ... I might be missing something (most likely) and you're probably talking about convention vs real electron flow but usually the negative is connected to the stripey side?
Ah, the can of worms than can result when describing semiconductors and conventional versus electron flow. My way of thinking about it (my opinion, not necessarily the best or correct analogy) is to think of the stripy side (the cathode) as more positive than the anode because electrons are moving away from the cathode towards the anode (making the cathode less negative, therefore more positive) from an electron flow perspective. In most circuits (not all) the cathode is therefore positive (a bridge rectifier circuit analogy may be easier to comprehend).
@@ralphj4012 Regardless of whether you are talking about conventional current or electron current (electron have a negative charge) the cathode or (stripey end) is negative with respect to the anode when the diode is conducting - just like it is with a thermionic diode.
@@ralphj4012If you need to refer to a bridge rectifier circuit to clarify an explanation, then your explanation is not simple at all. Try explaining current flow in a bridge rectifier to a room full of 19 year olds who would rather (and often are) on Tik-Tok rather than having their heads in the game. I once had that task, using a diagram showing conventional flow when I had learned it using electron flow. I discovered the ‘disconnect’ about 3/4 of the way through the lecture. I don’t think either the class or myself recovered that semester.
@@jeremiahchamberlin4499 Concur, always a challenge when adding comments as I never know who I am trying to (probably, badly) explain something to. I never try to be too specific (and in many cases don't bother) as it would take many pages or even another video to explain electron flow, and, as you say, those already indoctrinated by other 'information streams' are virtually impossible to educate (in my opinion),
I am not sure if the flexible pipe analogy is totally correct. In the example a force (current) is used to squeeze the pipe. In practice, more current to the base turns on the transistor (opens the pipe)?
I know that I was taught in middle-school (the 6th grade) science that the electrons are negative. Remedial recapitulation is required for some I suppose.
if they do not know what those components are they should not watch channels like this .. they should watch LER Learn Electronics Repair from richard he explains the transistors and diodes in full details with drawings and all this takes away of the things we have joined your channel for repairs ... sigh
![BLACK BAG - Official Trailer [HD] - Only in Theaters March 14](http://i.ytimg.com/vi/Du0Xp8WX_7I/mqdefault.jpg)
0:00 Intro
1:07 Comment about Diode polarity from Part 1 - Cathode/Anode/ + & -
4:23 Adding a third element to the P-N junction of the diode- in theory
4:50 Enter the transistor: The NPN junctions
5:36 How a transistor works - the water pipe analogy
7:27 PNP junction / PNP transistor - almost the same with opposite polarity
8:30 The "diode model" of an NPN transistor (the PNP would have the diodes reversed)
10:00 Comparing NPN "diode model" to a real NPN transistor
11:00 Using the multimeter in diode check mode to identify base-emitter-collector
12:21 Using a tester to measure hFE, Ic, & Vbe
13:22 Using a test circuit to understand these measurements
27:57 Looking at the transistor datasheet
29:15 Looking at forward and reverse breakdown voltages - and exceeding them
40:12 Discussing the results of the tests
45:08 Looking at a schematic to see how the transistor can fail
50:56 Looking at transistor emitter-base forward vs reverse voltage behavior
52:26 How current affects reverse breakdown voltage
54:09 Cutoff current
55:36 hFE (A.K.A. "gain" or "ß") - A moving target!
1:00:16 Vbe
1:00:59 Matching transistors - some comments
1:02:56 fT or gain bandwidth product, better known as transition frequency
1:08:36 Output capacitance and Miller effect (They are not the same!)
1:09:36 Noise level
1:10:29 Looking at some of the graphs and some final information
I look at the diode polarity in the circuit, a totally different way. In your example, you are not connecting the cathode to a positive voltage. The positive voltage is established by virtue of the way the diode is connected. It is only conducting through the positive half of the AC since wave. There is both positive and negative on the transformer side of the diode no matter what direction it is connected in the circuit.
Thanks for the shout out to the shut-in tinkerer community. Don't underestimate how many of us are here. And, not only for the electronics education, but for the content of your character that is so uplifting. For my purposes, your channel is the best on RUclips. And, I am not even a stereo guy... just general electronics. Best teacher, best content, best atmosphere. Thank you!
Even if "they" don't understand, "they" will, after watching your videos. Thanx, Tony. 👍
Bardeen, Shockley and Brattain all approve of this wonderful lesson. Thank you Tony. You are an excellent teacher! 73
RIP, little transistor, happily your life was not in vain. I learned so much about these mysterious components that have been a real blank page for me, thanks so much, Tony.
Excellent content. A Nobel Prize for developing a method to put the magic smoke back in.
You're by far one of the best Tony, thank you!
Xraytonyb, I could not help, but notice the black "NICE-POWER" branded power supply you have on your bench. I bought that same model power supply a few months ago, as well. Nice to see someone else thought it's a good one to have on the bench, with volts, amps and wattage read outs. I like the wattage read out feature. Keep up the good work on the instructional videos.
Time very well spent. Thank you.
Thank you for making those videos. Even as a master electrician I did not know much of this stuff! I am learning a ton from this channel for which I am very grateful. Please consider making a playlist with the basic theory videos and servicing 101 to make it easier for newcomers to your channel to find them.
Tony: I got a lot out of this video, as it helped me de-mystify much of the information found on a typical data sheet. I can sympathize with those who found the presentation frustrating; as you really ‘bit off more than you could chew’ through in a relatively short video. I have tried teaching the same topic with much less understanding than you to a class of mostly young men. Strangely, the teaching tool that I took away was your destructive testing. I think that such a demonstration would really get my students attention, and they might learn something. They manage to destroy them anyway, even when they’re not trying to (although sometimes they are).
I can certainly understand how the video ‘took a lot out of you,’ and you are a very good man for making the ‘Herculean’ effort to produce it in the first place. The topics you covered probably need to be broken down even further, and by the time you’re done you would have built an entire basic course in electronics over a range of twenty or so videos: which is not your main focus. It is my opinion that knowledge of basic electronics is revealed only to those who are both highly motivated and fairly intelligent with the curiosity and persistence to see it through to the end. You can ‘cast your bread upon the waters,’ but not everyone will be nourished thereby.
Thanks, that was pretty comprehensive, I know some things I didn't before, now!
thank you for taking time to set all this up for teaching purposes.. really helped me wrap my head around a lot of this. Might have to rewatch even later but thankful to have this info. you are a really good teacher. !
Really helpful. Thanks!
Great work !...cheers.
congratulations for the description of the topic very good
Thank you👍👍👍
Again a very good and ddetailed explanation, Tony!
Really helpful!! It clarified a lot of things that confused me.
Nice video, the flexible tube analogy is actually better suited for a FET than for a bipolar junction transistor.
I think I have to view these video's several times to grasp it. Being a language teacher at 71!
Bipolar Junction Transistors, are current driven. The Base Emitter juction, is the diode part of the transistor. This produces the forward current, which allows the Collector to produce the amplified current, to drive the circuit!
If you watched the video, you wouldn't have needed to type that 😏😏
Excellent Tony! Thank you!
Great video. Really needed this, thanks!
Thanks Tony. Liked your commitment to education (the magic smoke)
Hello Tony , thank you for sharing ................I have some old (metal body) diodes where the cathode is indeed labeld with a +..... can be confusing when you don't know it !
Yeah especially if your just starting out !:)
Very Nice Vid Well Explained Thanks for Sharing Really Enjoyed it
Tony,
Tangentially related comment: I have the same backlight tester, and the readability is indeed terrible. I had some improvement bay simply using a red marker to color some transparent tape, and covered the display with that. It does reduce the visibility of the non-illuminated segments, and enhances the visibility of the lighted ones. It would have been so simple - and inexpensive for the mfr to do this. I don’t think I’ll ever be able to fathom the logic processes used by Chinese bean counters.
Can't thank you enough for this review of transistor theory. Cleared out alot of cobwebs for me. Enjoyed!
I was interested in seeing how you would describe the operation of these devices. The workings of a vacuum tube are quite intuitive and easy to explain. Not so with semiconductors. The explanations are necessarily abstract and can be difficult to wrap your head around so kudos for this video. The only criticism I might make is that in your water analogy, you implied that instead of turning the transistor on, the base current chokes off the current. That is how a FET operates.
Incidentally, I wasn't sure you had the cathode/anode designations on the diode correct until I realized that in your diagram, the diode is reverse biased. The way I remember it is the cathode is the negative end of the diode and the anode is the positive end when the diode is forward biased (conducting).
I would rather see the transistor tester on the bench than a stereo.
The spec sheet for the transistor indicates that the breakdown voltage is listed under the heading “min”. But your explanation is that it is a maximum voltage that should not be exceeded, which makes perfect sense. Can you explain why the confusion? Thanks for all you do to educate us.
If you test a lot of this transistors you will find out, that not all of them will start to break down at 120V, but you will get a range of values of breakdown voltages. The manufacturer usually does the same and adds a saftey margin. The value which comes in the datasheet is the minimum of the spread of voltages (+ margin), therefore it is in the min section. Take also care that this value is only valid at 25°C ambient temperature! But for your design this is the maximum value which should appear worst case. Usually you should stay well below.
Thanks, Tony. Herculean effort for.something that most would find, well, boring. Thank goodness I'm not one of those. I watched all the way through since it is really interesting.
Hey, do you know why it's called a transistor? Its a good story as well.
"Transistor" is short for "transfer resistance". It got that name because it is a current dual of a vacuum tube which is characterized by a "mutual conductance".
Regarding the diode "see that stripe, that's going to be your cathode, even though you connect the positive to it" ... I might be missing something (most likely) and you're probably talking about convention vs real electron flow but usually the negative is connected to the stripey side?
Ah, the can of worms than can result when describing semiconductors and conventional versus electron flow. My way of thinking about it (my opinion, not necessarily the best or correct analogy) is to think of the stripy side (the cathode) as more positive than the anode because electrons are moving away from the cathode towards the anode (making the cathode less negative, therefore more positive) from an electron flow perspective. In most circuits (not all) the cathode is therefore positive (a bridge rectifier circuit analogy may be easier to comprehend).
@@ralphj4012 Regardless of whether you are talking about conventional current or electron current (electron have a negative charge) the cathode or (stripey end) is negative with respect to the anode when the diode is conducting - just like it is with a thermionic diode.
@@ralphj4012If you need to refer to a bridge rectifier circuit to clarify an explanation, then your explanation is not simple at all. Try explaining current flow in a bridge rectifier to a room full of 19 year olds who would rather (and often are) on Tik-Tok rather than having their heads in the game. I once had that task, using a diagram showing conventional flow when I had learned it using electron flow. I discovered the ‘disconnect’ about 3/4 of the way through the lecture. I don’t think either the class or myself recovered that semester.
@@jeremiahchamberlin4499 Concur, always a challenge when adding comments as I never know who I am trying to (probably, badly) explain something to. I never try to be too specific (and in many cases don't bother) as it would take many pages or even another video to explain electron flow, and, as you say, those already indoctrinated by other 'information streams' are virtually impossible to educate (in my opinion),
I am not sure if the flexible pipe analogy is totally correct. In the example a force (current) is used to squeeze the pipe. In practice, more current to the base turns on the transistor (opens the pipe)?
I know that I was taught in middle-school (the 6th grade) science that the electrons are negative. Remedial recapitulation is required for some I suppose.
I bought that same power supply last winter..what do you think of it..did you review it at all during a video already somewhere
I have a Japanese made FET TransiStar amp that I can't find any repair info on. Anyone? Anyone?
That ain't much to go on Lol !
if they do not know what those components are they should not watch channels like this .. they should watch LER Learn Electronics Repair from richard he explains the transistors and diodes in full details with drawings and all this takes away of the things we have joined your channel for repairs ... sigh
Don't do that, telling people what they should do!