I am 83 years old and came across your You Tube channel by accident I started in electronics when I was about 15 years old I wish you were my instructor you are a very a good instructor I I knew how things worked but never knew the theory. I love trouble trouble shooting and watching your videos has giving me a better outlook. Keep up the good work looking forward to future videos. Merrill.
I taught myself on tube circuits, learned solid state in school, worked on equipment from the 50’s and older in my first job (anyone else seen reed type freq meters), ended up working in state of the art internet backbone equipment, and now feel old at 60 after hearing all these tube terms again.
@@JackClayton123 , Have no fear, everyone feels a bit humble after a few of Mr. Carlson's videos. LOL I'll be 78 soon myself, been there... done that stuff. Know how difficult it is, also.
If you were my electrics teacher in college I would have probably pursued an electrical engineering degree. Your explanations are clear and easy to understand! Thanks!
Zener diodes from 4.7 to 5.6 volts are temperature stable if the correct current is used. This is because the zener and avalanche currents within the diode cancel. Zener voltages above 5.6 volts are avalanche current dominated, which means the zener voltage will increase as temperature is increased.
Bill Harris , Exactly what I was thinking. The two different mechanisms in zener diodes is due to two different types of breakdown, the zener effect due to heavily doped diodes, and the avalanche effect due to the lighter doping. When these two effects cancel, you get a VERY rare event... a stable "zener reference diode." Very difficult to process and extremely valuable to references of all types such as current and frequency standards. de KQ2E
+TheChipmunk2008: ...SED, must be a relative of an SDR which stands for a Sight Dependent Resistor whose resistance is directly proportional to the intensity of the gaze, symbolized by a profile of an eye ball looking at the direction of the resistor with couple of arrows as in an LED symbol aiming at the resistor. Sadly, can't claim this one as my own, I got it from someone else years ago. All the best. Mark G
I have just used a Zener instead of a gas tube for stabilising a transmitter tube VFO. This morning spending my time searching for slightly wobbling frequency! Thank you for the excellent video.
Paul, your such a nerd - but the world sure dose need you - your explanations of electronics in your vids is so engaging and simple even I can understand them. Please keep at it.
Enjoyed the video. Showing my age. I've worked with gas regulators, thyratrons, klystrons, magnetrons, and traveling wave tube amplifiers during my 22 years in the Navy! The Navy is slow to change. I was still working on vacuum tube equipment when I retired in 1991 while stationed at a Mobile Technical Unit. "If it isn't broken, don't fix it" is an adage I heard numerous times.
Very cool demo with the gas diode tube. That is incredible accuracy for sure. It makes sense those are found in the high-end instruments you mentioned.
You have really stepped up your game! This is a wonderful explanation of Zener diodes. To those just getting started, it may be a bit deep, but for me it is a good review. You do a great presentation so may I request more videos on tube amps. You have done some, which were great, and more is better! Thankz
I am enjoying your excellent presentations, you truly do a good job. I have an EE degree and have been working in the Silicon Valley for many years, so I always smile at the subtle differences on how we articulate two words. From the US perspective, Solder is pronounced "sodder" and a Zener is pronounce "zeener". For anyone who is learning or reviewing electronics, your efforts are truly wonderful. All the very best. Cheers
Mr. Carlson on the whiteboard--------time to pay attention and I might learn something. I really enjoy how you present theory, then withdraw to the lab and demonstrate what you just told us. Thanks.
I haven't actually bothered to look into electronics for years, but the way you explain things makes me rediscover an old love... Thanks for your brilliant video's. You should consider being a teacher. You're very good at it!
After 13 hours of work today this was very relaxing to come home to. Very well done Paul. I enjoyed every minute of it. Thanks for taking the time to post these tutorials.And you know you just cannot beat a good ole tube. Big thumbs up.
Excellent instruction, I've had a tough time remembering the differences between diode types and their properties, and it's crystal clear now. Thanks a lot! Your teaching style is fantastic.
Hi Paul, I know this is an old vid, but thanks for it - I managed to re-learn and refresh my knowledge of how tubes and diodes work. I always struggled with tubes BITD, and you make it so clear.
Different technologies have their preferred voltage range. The ideal voltage for a zener is around 5.2 volts. At this voltage, they tend to have a low temperature coefficient since the avalanche and zener effects both play a role and have opposing temperature coefficients. You will also notice that zeners 5.2v and slightly above tend to exhibit a sharp regulation curve. Solid state circuits tend to work at much lower voltages than thermionic circuits so it is a case of horses for courses. If you really wanted to replace an 85v regulator tube with solid state, and retain a low temperature coefficient, you could stack a bunch of 5.2v zeners to give the necessary voltage, or use a transistor, 2 resistors and a 5.2v zener to make a programmable shunt. In NPN configuration, collector to regulated rail. Voltage divider (potentiometer or 2 resistors) on base, zener (or TL431) on emitter. When voltage divider delivers more than 6v to base, transistor starts conducting. Given the poor temperature coefficient and poor regulating curve for low voltage zeners (below 5.2v), I tend to use forward biased LEDs and rectifier diodes for lower voltages, or a programmable shunt regulator such as a TL431 which, with the addition of a couple of resistors, is a superior replacement for zeners in most applications up to 36v and cost a penny. In short, zeners are cheap, easy to use but remember they are crude and have a very narrow window of precision. If you want precision, then there are solid state tecniques other than zener diodes to perform the function. The tube voltage reference is new to me, and I am fascinated in some of these thermionic and gas tube techniques. Thank you for sharing your knowledge of these older technologies with us.
Another very interesting video once again, the tube regulator somewhat amazed me. Many years ago I was involved in the design of a power supply that had to operate over an extremely wide temperature range (-50c to +60c). One of the greatest challenges was to get the over current protection to work consistently over that range. Bizarrely a voltage reference using a constant current source and a resistor was the answer. Over such a wide temperature range the usual monitoring of voltage across an emitter resistor became tricky.... you can't just use a sense transistor to shut down the supply when the emitter resistor drop becomes greater than 0.6v. Your video helps to highlight this.
NE2 pilot light bulbs also double as VR tubes in some devices. Thus, if replacing an older NE2 power-on indicator light with an LED or a conventional filament bulb, make sure the NE2 is NOT part of the power supply circuit as a VR tube!
When you need a really stable semiconductor reference, it's usually better to use a well-designed voltage reference IC like the TL431, which has a sharper knee and an adjustable "zener voltage", and temperature compensation--it's available in grades (the TL431C from TI, in SOT-23 package specifically) that are guaranteed not to exceed 16 mV reference deviation over the entire -40 °C to 125 °C operating range. The only concern then is the temperature coefficient of the resistors you use to set the output voltage (if you set it to something other than the 2.5 V it gives without the resistors), and that you can compensate for using a resistor network with matched tempco, or just really low-tempco resistors (depending on how much you're willing to spend, it's not that hard to get resistors with tempco as low as ±0.2 ppm/°C; Vishay sells them for about $6-$7 each. Very expensive for a resistor, but affordable for a one-off if you really need it). And then of course there's stuff like the LTZ1000, hyper-stable low-noise reference with a built-in heater for temperature control; stick one of those in a styrofoam oven and servo the temperature to a constant 50 °C and you basically have a metrology-grade voltage reference. They don't come cheap, though--about $70 on digikey. All that to say, zener diodes alone aren't usually what you'd use if you need an extremely stable and predictable reference voltage. They're more for when you don't care if your reference is off by a few percent and changes a bit with temperature, you just need "about 5 volts" or "about 12 volts" or whatever.
Paul i enjoy your videos very much and I am very sorry if my reference to the compressor again I was referencing the engineering of the original flywheel not being any reflection of you or your abilities witch are both over the top thank you for your educational stuff
You have told your fans that you read the comments and as impressive as that is i would not expect any thing less your over the top thank you so much I watch most at night when I can't sleep things are kinda screwed up in the world and the more explain the circuit the more interesting it is its like not being able to.put down a good book Thanks again Paul from the epic center of the virus Michigan Thank The good Lord I have had the Pfizer shot
Excellent tutorial on the problems one can encounter with zener diodes. I ran into the zener drift issue about 20 years ago when I was building a 6.2 volt regulated supply using the zener as the voltage reference. I solved it by introducing a series JFET current regulator to feed the zener and the drift was dramatically reduced.
Excellent tutorial. Brings me back to my days in the lab. One thing - maybe it's just me with a couple extra decades behind me and faulty memory - your homebrew curve tracer looks to me to be mirror flipped around the vertical axis. My memory of the IV trace of the diode would have the +V on the right and -V on the left... But it really doesn't matter - you're absolutely accurate in any case. Thanks for what you put into this.
+TRXBench Thanks Peter! I'm still working on that troubleshooting video, there's not enough time in the week for all this. This TTT could almost be a full time job.
+BobEckert56 Thanks for the kind words Bob! I have a ton (literally) of Heathkit stuff. Some day much of it will become video's. I have Three DX-100's just itch'n for a video.
Regardless what the subject matter may be, I never fail to learn something from your tutorials! Always as interesting as they are informative, I wish to thank you once again for sharing your knowledge Mr. C.!
When in the Army, amongst a bunch of other equipment, I fixed RT-524A/VRC transievers (completely discreet components) and there was one gas diode in there because (for reasons/what circuit I have forgotten) an unwavering voltage control was needed no matter what temperature the thing was running at.
That observation alone kicked me out of my boots. Incredible! I deal sometimes with tubes, but never had opportunity to work with this kind. Interesting!
that's amazing. I have tons of gas diodes on stock, didn't experiment myself (yet), and I am totally impressed by the accuracy. We call them Stabi, here in german language. Or even Stabivolt (whioch was a brand name vor gas diodes). 85A2. 108C1, and so on.
i have not seen a curve tracer since the 80's in collage. since then i have used a "huntron tracker" to do the same thing, great for a quick test on aluminum electrolytic caps. great video
You are absolutely the best instructor on the topics you cover I have ever encountered. I wish I were 10 years old right now so I could start off in a career in electronics the right way, and with your help I'd have had a chance! When I started tinkering it was all tube amps and radios, transistor types were too valuable to disassemble if you didn't know what you were doing! The bet resource back then was the US Navy Radioman's guide. (still quite a good resource) But if I had a question I was out of luck. The local HAM I knew was a curmudgeonly fellow that didn't take well to simple questions. (I think he hated children) I have been an instructor in many fields, from teaching flying aircraft by instruments to an A+ certification class for entry level computer techs. I can say with authority that you have a unique approach, which unfortunately I cannot describe easily except to say you are efficient and highly effective. If I were still teaching I'd borrow a page or three from your book for sure. One thing I notice you do is you toss out information 'ahead of schedule,' so to speak. You will casually drop some advanced information, such as the function of a circuit, at a point where the fundamentals behind it have not yet been entirely covered. Like foreshadowing in a novel. the mind is made 'hungry' for the details that will build the final picture. You use this to great effect, whether consciously or not I can't say. Either way, you are a natural,. I really appreciate that you take the time to post all this wonderful information, I can't thank you enough. Cliff Jones Horseheads, New York.
> curmudgeonly If you couldn't get much out of him, it might be the curmudgeon was actually, simply, not-a-good teacher. Also, you have to know the material thoroughly if you're going to explain it, and if you get a real exceptional student, your ego has to be willing to say I Don't Know if the student pushes the limits of your knowledge. If you're fearful of being pushed to your limit, you might not want to start explaining anything. A good teacher enjoys considering the level of the student and improvising explanations - backing up and putting if necessary - so it's ultimately and completely understandable. Some people got got the teaching bone; some people don't.
At first when I saw this video was 31min long I thought I'd be snoring by the end. I was pleasantly surprised at how interesting it was. Good job. Found it very useful.
Howdy! Thanks for the wonderful explanation. I received a MASSIVE, well for me anyhow, misc, sort of grab box filled from top to bottom with loose components. Thousands of resistors, hundreds of diodes and dozens of other components, capacitors and many that I cannot even identify, I believe go back to the days of the Automatic Electric Step in house telephone switching system. Now my old eyes aren't what they used to be, so I hooked up my cheap little microscope so I could read the codes on the tiny glass diodes and such. It has taken me three solid days just to separate the devices into categorize, and now that I have that sort done, I plan to sort the diodes into four basic groups. Rectifiers, High Speed Switching, Zener, and Shotkey. This video goes a long way into understanding why these are needed. I got the stuff from the Electronic Goldmine in Arizona. The parts are ALL top grade devices, none of the chinese clone crap, just sorting them made me feel a bit upgraded from circuit hack to perhaps a circuit builder.
In my tech school in the early 70s we mostly studied solid state circuitry and didn't dwell on tube theory as much but when I graduated and got into servicing tube equipment I learned there was a lot of difference with the pros and cons of each. High powered RF applications deployed a lot of tube circuitry and were pretty durable and in a lot of ways were preferred over solid state PA circuits. The ole tube was more forgiving with high SWR versus the solid state RF amps. :)
+Dennis Petersen This is why microwave ovens don't have transistors doing the work. Transistors are very sensitive to load and impedance variations. SWR (Standing Wave Ratio) is a real issue with transistors, where tubes are much more tolerant. Thanks for your comment Dennis!
Paul, You make electronics simple and interesting. I wish I had you for a teacher way back when I was in Electronics Technology school. I am in awe of your knowledge and your talent for explaining things. Thank you, Thank you, Thank you. John K4AGO
Real good review for me on the zener diodes and you might say that tubes are hard to beat in many applications. The tube has it's own temperature control built in much like a crystal oven for precise frequency control. :) Many thanks for showing the video review!
You are talking about current 'going across' and voltage 'going through'. A very interesting video but the switching around of voltage and current could be confusing. Still very interesting and worth a thumbs up.
OD3s have a beautiful neon Purple glow, IMHO. I understand the OA2s have some light sensitivity that can effect their performance, but I'm not sure how that works. I would love to see you explain the details of the different gas tube regulators!
Awesome ,seeing the tube takes me back to school when I was given a tube and you have to look in the tube to identify the heating element pin ,the anode ,the cathode , the grid ,the screen grid the control grid depending on the tube given ,awesome on explaining the use of a Zener diode , love it lol I need more
Thanks - really enjoy your tech tips and longer videos! Your curve tracer is awesome. I built one but it's external to my scope and doesn't have the capability you've designed into yours. I'd be really interested to see more on this. Anyway, thanks again!
I like to draw the "whisks" of the zener at 45 degree angle and make them pretty long, this makes it easier to read and distinguishes better from a Shottky symbol.
So how do they manufacture a 5651 tube with such accuracy. That accuracy has to be based entirely on the composition of the internal gas is it not? Is it "tweeked" before sealing off the tube? I really enjoy your showing comparisons between solid state and vacuum tube circuits. It makes understanding of the solid state bits a little more clearer.
+hankus253 They had lost of tricks up their sleeves back in the day. The accuracy involved in building a tube, and the consistency in the resultant final test readings is often better then their solid state counterparts. Many of these tubes ended up in military electronics way back when.
Very interesting about the vacuum tube verses the zener diode unfortunatly I missed the valve era by maybe a decade being old enough to understand the theroy of the vacuum tube. I remember my father building a 2 meter valve transmitter and his all valve SSB phaseing exciter for HF he still uses his valve linear with his Kenwood TS120V. I thought the zener would be more stable than the valve voltage regulator but the opposite seems to be true. Thanks again for your time and effort. Regards David Grey By the way the linear uses a pair of 807's still going strong from the 70's.
Very cool to see the tube beat silicon at the end. It would be neat to see the curve trace of the tube diode. I’m not guessing 85 volt curve tracers are very common though haha
I stumbled on to your channel. I like how your methods of teaching as in a clear explanation & then a demonstration. But I do have one question. Why do you use the Conventional flow instead of the Electron flow for your teachings?
Thanks for doing these excellent videos. it would also be instructive to include a comparison of the tube VS zener with regard to load current fluctuations and supply voltage fluctuations.
+Mr Carlson's Lab I just love the way you do videos.You never assume that every one already is advanced electronics. I have learned more hear then all the books and math that I learned in school.I first really got interested in electronics when I had to pass a general class amateur radio test years ago . I think I'm going to get back to basics in stead of just being a appliance operator .Thank you Paul.
I am fixing tube amplifier for many years, modern amplifier like Audio Research use all the rectifier section and regulation with solid state components and the audio path with vacuum tubes. Cheers.
Hi Paul, I don't usually write a comment to any of your video's as their context is beyond my scope of understanding. (especially RF tuning and aligning) However, I do thoroughly enjoy watching the resurrection and restoration of the vintage equipment you repair (sometimes brilliantly incorporating modern components to do so). I also eagerly await new Tech Tip Tuesday uploads as one would watch a favorite TV show ;) I wanted to ask if perhaps you could make a video explaining the differences between Class A, B, A/B, and C amplifier designs? And SET and PP and their relationship to the different classes? I hear a lot of mixed up explanations on the web, which just adds to my confusion (and most likely others) on the subject. I know it's a big undertaking and a lot to ask for, but as is said, the squeaky wheel gets the grease and if you don't ask it will never happen. I will understand if you are too busy with other projects and subjects, and don't have the time to do so. Either way keep up the great video's and topics and I will continue to watch. Thanks, Tom
+Bucyrus Erie12 Hi Tom. I will put that on my "to do" list. I have a video coming shortly, hopefully up this weekend. Glad your enjoying the video's, and thanks for the kind words too!
29:00 Hi Mr. Carlson, just curious and concerned that you aren't too worried working with 85VDC where anything over 30VDC is considered lethal/hazardous; sure, your current draw is ~4.5mA but isn't this still dangerous?
Hi Mr.Carlson my name is Luc and I really enjoy your videos.I was wondering if you would like to show us how you do a test on a vacuum tube amplifier to check for distortions and the way you would go about fixing the problem.And if your up for it you could include a tutorial on how to set up your equipment before you do the actual testing on this amplifier.
Thanks for the video. Would like to see other video's of circuit "building blocks". Eg CCS, oscillators, RC filters, LTP, cathode follower etc. A few formulae would be good too. Also VERY interested to see your circuit/build of the Eico scope curve tracer.
Could you do a tech video on Darlington transistors.... I never quite understood thier purposes...Tho we saw them often in older TV's, didn't see many later on. Also, shottky diode. Thank you Paul.🙂
I am 83 years old and came across your You Tube channel by accident I started in electronics when I was about 15 years old I wish you were my instructor you are a very a good instructor I I knew how things worked but never knew the theory. I love trouble trouble shooting and watching your videos has giving me a better outlook. Keep up the good work looking forward to future videos.
Merrill.
Thanks for your kind comment Merrill!
I taught myself on tube circuits, learned solid state in school, worked on equipment from the 50’s and older in my first job (anyone else seen reed type freq meters), ended up working in state of the art internet backbone equipment, and now feel old at 60 after hearing all these tube terms again.
@@JackClayton123 , Have no fear, everyone feels a bit humble after a few of Mr. Carlson's videos. LOL I'll be 78 soon myself, been there... done that stuff. Know how difficult it is, also.
I never saw and heard a teacher who explains difficult things in such an easy, clear and understandable way, Mr Carlson, Sir!! Thank you so much!!
You're very welcome!
If you were my electrics teacher in college I would have probably pursued an electrical engineering degree. Your explanations are clear and easy to understand! Thanks!
Hi Ignacio. Glad your finding these video's useful.
I was thinking the same xD
@@MrCarlsonsLab 8⁸⁸
Zener diodes from 4.7 to 5.6 volts are temperature stable if the correct current is used. This is because the zener and avalanche currents within the diode cancel. Zener voltages above 5.6 volts are avalanche current dominated, which means the zener voltage will increase as temperature is increased.
Bill Harris , Exactly what I was thinking. The two different mechanisms in zener diodes is due to two different types of breakdown, the zener effect due to heavily doped diodes, and the avalanche effect due to the lighter doping. When these two effects cancel, you get a VERY rare event... a stable "zener reference diode." Very difficult to process and extremely valuable to references of all types such as current and frequency standards. de KQ2E
Thanks Mr. Carlson , you're a gifted instructor , easy to follow .
+Harry Giberson
Thanks Harry!
A diode that's massively overloaded becomes (momentarily) an SED (smoke emitting diode)
That's not smoke, it's the electrons escaping. 😉
+TheChipmunk2008 or in german language, the rectifier is called Gleichrichter. Which pretty much sounds like *gleich riecht er* (smell soon).
+TheChipmunk2008
LOL... SED, I may have to use that 8^)
+TheChipmunk2008:
...SED, must be a relative of an SDR which stands for a Sight Dependent Resistor whose resistance is directly proportional to the intensity of the gaze, symbolized by a profile of an eye ball looking at the direction of the resistor with couple of arrows as in an LED symbol aiming at the resistor.
Sadly, can't claim this one as my own, I got it from someone else years ago.
All the best.
Mark G
+TheChipmunk2008 An LED also becomes an SED momentarily, but after final collapse, becomes a DED (Dark emitting diode)...
Now it's "vacuum tubes work like a FET".
Back in the day: "FETs work like a pentode".
Another little statement that makes me feel old.
I have just used a Zener instead of a gas tube for stabilising a transmitter tube VFO. This morning spending my time searching for slightly wobbling frequency! Thank you for the excellent video.
So old school tubes are more stable than solid state parts, amazing. Great job schooling us ol' hacks, thanks for teaching us all.
+Sam Iam
Hi Sam, you would be surprised how much better some of the old stuff is. Thanks for your kind comment!
Paul, your such a nerd - but the world sure dose need you - your explanations of electronics in your vids is so engaging and simple even I can understand them. Please keep at it.
Enjoyed the video. Showing my age. I've worked with gas regulators, thyratrons, klystrons, magnetrons, and traveling wave tube amplifiers during my 22 years in the Navy! The Navy is slow to change. I was still working on vacuum tube equipment when I retired in 1991 while stationed at a Mobile Technical Unit. "If it isn't broken, don't fix it" is an adage I heard numerous times.
Vacuum tubes are not affected by EMP's - that was a big reason military kept using them.
Very cool demo with the gas diode tube. That is incredible accuracy for sure. It makes sense those are found in the high-end instruments you mentioned.
You have really stepped up your game! This is a wonderful explanation of Zener diodes. To those just getting started, it may be a bit deep, but for me it is a good review. You do a great presentation so may I request more videos on tube amps. You have done some, which were great, and more is better! Thankz
+Audio Tech Labs
Thanks for the kind words!
I am enjoying your excellent presentations, you truly do a good job. I have an EE degree and have been working in the Silicon Valley for many years, so I always smile at the subtle differences on how we articulate two words. From the US perspective, Solder is pronounced "sodder" and a Zener is pronounce "zeener".
For anyone who is learning or reviewing electronics, your efforts are truly wonderful. All the very best.
Cheers
Mr. Carlson on the whiteboard--------time to pay attention and I might learn something. I really enjoy how you present theory, then withdraw to the lab and demonstrate what you just told us. Thanks.
I haven't actually bothered to look into electronics for years, but the way you explain things makes me rediscover an old love... Thanks for your brilliant video's. You should consider being a teacher. You're very good at it!
+Rene Voortwist
Thanks for the kind words Rene! Glad your enjoying the video's.
"Here's a curve tracer I quickly knocked up one day... with screensaver" :D
After 13 hours of work today this was very relaxing to come home to. Very well done Paul. I enjoyed every minute of it. Thanks for taking the time to post these tutorials.And you know you just cannot beat a good ole tube. Big thumbs up.
+The Radio Shop
Thanks Buddy! Looking forward to your next video as well! You and Peter make great video's!
+Mr Carlson's Lab You are very welcome :-)
Excellent instruction, I've had a tough time remembering the differences between diode types and their properties, and it's crystal clear now. Thanks a lot! Your teaching style is fantastic.
Thanks for your feedback!
Hi Paul, I know this is an old vid, but thanks for it - I managed to re-learn and refresh my knowledge of how tubes and diodes work. I always struggled with tubes BITD, and you make it so clear.
Different technologies have their preferred voltage range. The ideal voltage for a zener is around 5.2 volts. At this voltage, they tend to have a low temperature coefficient since the avalanche and zener effects both play a role and have opposing temperature coefficients. You will also notice that zeners 5.2v and slightly above tend to exhibit a sharp regulation curve.
Solid state circuits tend to work at much lower voltages than thermionic circuits so it is a case of horses for courses. If you really wanted to replace an 85v regulator tube with solid state, and retain a low temperature coefficient, you could stack a bunch of 5.2v zeners to give the necessary voltage, or use a transistor, 2 resistors and a 5.2v zener to make a programmable shunt. In NPN configuration, collector to regulated rail. Voltage divider (potentiometer or 2 resistors) on base, zener (or TL431) on emitter. When voltage divider delivers more than 6v to base, transistor starts conducting.
Given the poor temperature coefficient and poor regulating curve for low voltage zeners (below 5.2v), I tend to use forward biased LEDs and rectifier diodes for lower voltages, or a programmable shunt regulator such as a TL431 which, with the addition of a couple of resistors, is a superior replacement for zeners in most applications up to 36v and cost a penny.
In short, zeners are cheap, easy to use but remember they are crude and have a very narrow window of precision. If you want precision, then there are solid state tecniques other than zener diodes to perform the function.
The tube voltage reference is new to me, and I am fascinated in some of these thermionic and gas tube techniques. Thank you for sharing your knowledge of these older technologies with us.
+Nick Hill
Thanks for taking the time to write Nick! Lots of great info there.
Another very interesting video once again, the tube regulator somewhat amazed me. Many years ago I was involved in the design of a power supply that had to operate over an extremely wide temperature range (-50c to +60c). One of the greatest challenges was to get the over current protection to work consistently over that range. Bizarrely a voltage reference using a constant current source and a resistor was the answer.
Over such a wide temperature range the usual monitoring of voltage across an emitter resistor became tricky.... you can't just use a sense transistor to shut down the supply when the emitter resistor drop becomes greater than 0.6v. Your video helps to highlight this.
+g0fvt
Great read. Thanks for the story!
NE2 pilot light bulbs also double as VR tubes in some devices. Thus, if replacing an older NE2 power-on indicator light with an LED or a conventional filament bulb, make sure the NE2 is NOT part of the power supply circuit as a VR tube!
When you need a really stable semiconductor reference, it's usually better to use a well-designed voltage reference IC like the TL431, which has a sharper knee and an adjustable "zener voltage", and temperature compensation--it's available in grades (the TL431C from TI, in SOT-23 package specifically) that are guaranteed not to exceed 16 mV reference deviation over the entire -40 °C to 125 °C operating range. The only concern then is the temperature coefficient of the resistors you use to set the output voltage (if you set it to something other than the 2.5 V it gives without the resistors), and that you can compensate for using a resistor network with matched tempco, or just really low-tempco resistors (depending on how much you're willing to spend, it's not that hard to get resistors with tempco as low as ±0.2 ppm/°C; Vishay sells them for about $6-$7 each. Very expensive for a resistor, but affordable for a one-off if you really need it).
And then of course there's stuff like the LTZ1000, hyper-stable low-noise reference with a built-in heater for temperature control; stick one of those in a styrofoam oven and servo the temperature to a constant 50 °C and you basically have a metrology-grade voltage reference. They don't come cheap, though--about $70 on digikey.
All that to say, zener diodes alone aren't usually what you'd use if you need an extremely stable and predictable reference voltage. They're more for when you don't care if your reference is off by a few percent and changes a bit with temperature, you just need "about 5 volts" or "about 12 volts" or whatever.
Paul i enjoy your videos very much and I am very sorry if my reference to the compressor again I was referencing the engineering of the original flywheel not being any reflection of you or your abilities witch are both over the top thank you for your educational stuff
No worries Paul!
You have told your fans that you read the comments and as impressive as that is i would not expect any thing less your over the top thank you so much I watch most at night when I can't sleep things are kinda screwed up in the world and the more explain the circuit the more interesting it is its like not being able to.put down a good book
Thanks again
Paul from the epic center of the virus Michigan
Thank The good Lord
I have had the Pfizer shot
Excellent tutorial on the problems one can encounter with zener diodes. I ran into the zener drift issue about 20 years ago when I was building a 6.2 volt regulated supply using the zener as the voltage reference. I solved it by introducing a series JFET current regulator to feed the zener and the drift was dramatically reduced.
+Richard Melville
Interesting! Thanks for your input.
Excellent tutorial. Brings me back to my days in the lab. One thing - maybe it's just me with a couple extra decades behind me and faulty memory - your homebrew curve tracer looks to me to be mirror flipped around the vertical axis. My memory of the IV trace of the diode would have the +V on the right and -V on the left... But it really doesn't matter - you're absolutely accurate in any case. Thanks for what you put into this.
Another excellent starter tutorial! Take care
+TRXBench
Thanks Peter! I'm still working on that troubleshooting video, there's not enough time in the week for all this. This TTT could almost be a full time job.
+Mr Carlson's Lab Yeah Paul I exactly know what you are talking about. It really takes a lot of time. Talk to you soon!
That tube is really impressive. Holding the voltage steady. Lot of great info Mr Carlson it's a big help to me thanks for sharing.
+wade hicks
Glad you enjoyed Wade!
Really terrific session. Love that Heathkit voltmeter with the Nixie display. I am a lifelong Heathkit builder and now collector. A true Heathkitnic.
+BobEckert56
Thanks for the kind words Bob! I have a ton (literally) of Heathkit stuff. Some day much of it will become video's. I have Three DX-100's just itch'n for a video.
Mr Carlson's Lab I had a feeling you'd say you were also a Heathkitnic. We are a motley crew!
Thank You, Thank You, Thank You. 'Dumbing' it down to a level that I understand... Your a great teacher and your visuals are excellent.
Thanks! Glad you're enjoying the video's!
Regardless what the subject matter may be, I never fail to learn something from your tutorials! Always as interesting as they are informative, I wish to thank you once again for sharing your knowledge Mr. C.!
+Anthony Reo
Glad to share Anthony!
Nice video for a refresher for my 70 yr old mind
thanks Paul
+DENNIS N
Your welcome Dennis!
When in the Army, amongst a bunch of other equipment, I fixed RT-524A/VRC transievers (completely discreet components) and there was one gas diode in there because (for reasons/what circuit I have forgotten) an unwavering voltage control was needed no matter what temperature the thing was running at.
A very good and precise explanation. Well done as always.
+Michael Beeny
Thanks Michael!
be cool to hear that 1 hour discussion of the full details of that circuit!
the tube never gets under 85...amazing, and much more beautifull aswell 😆
I agree!
That observation alone kicked me out of my boots. Incredible! I deal sometimes with tubes, but never had opportunity to work with this kind. Interesting!
Thanks, Paul. It's always nice to have refresher courses on components.
+Beretta96Dan
Glad you enjoyed Dan!
that's amazing. I have tons of gas diodes on stock, didn't experiment myself (yet), and I am totally impressed by the accuracy. We call them Stabi, here in german language. Or even Stabivolt (whioch was a brand name vor gas diodes). 85A2. 108C1, and so on.
+Max Koschuh
Great! Glad your interested in experimenting with them.
Your videos are extremely informative and very well done. Thanks for putting so much time and hard work into it
Thanks for keeping your youtube classes online for so long.
i have not seen a curve tracer since the 80's in collage. since then i have used a "huntron tracker" to do the same thing, great for a quick test on aluminum electrolytic caps. great video
+john cajka
Thanks John!
You are absolutely the best instructor on the topics you cover I have ever encountered. I wish I were 10 years old right now so I could start off in a career in electronics the right way, and with your help I'd have had a chance!
When I started tinkering it was all tube amps and radios, transistor types were too valuable to disassemble if you didn't know what you were doing! The bet resource back then was the US Navy Radioman's guide. (still quite a good resource) But if I had a question I was out of luck. The local HAM I knew was a curmudgeonly fellow that didn't take well to simple questions. (I think he hated children)
I have been an instructor in many fields, from teaching flying aircraft by instruments to an A+ certification class for entry level computer techs. I can say with authority that you have a unique approach, which unfortunately I cannot describe easily except to say you are efficient and highly effective. If I were still teaching I'd borrow a page or three from your book for sure.
One thing I notice you do is you toss out information 'ahead of schedule,' so to speak. You will casually drop some advanced information, such as the function of a circuit, at a point where the fundamentals behind it have not yet been entirely covered. Like foreshadowing in a novel. the mind is made 'hungry' for the details that will build the final picture. You use this to great effect, whether consciously or not I can't say. Either way, you are a natural,.
I really appreciate that you take the time to post all this wonderful information, I can't thank you enough.
Cliff Jones
Horseheads, New York.
Thanks for your kind words Cliff! I appreciate you taking the time to write.
catw0rld
bravo sir!!
> curmudgeonly
If you couldn't get much out of him, it might be the curmudgeon was actually, simply, not-a-good teacher.
Also, you have to know the material thoroughly if you're going to explain it, and if you get a real exceptional student, your ego has to be willing to say I Don't Know if the student pushes the limits of your knowledge. If you're fearful of being pushed to your limit, you might not want to start explaining anything.
A good teacher enjoys considering the level of the student and improvising explanations - backing up and putting if necessary - so it's ultimately and completely understandable. Some people got got the teaching bone; some people don't.
At first when I saw this video was 31min long I thought I'd be snoring by the end. I was pleasantly surprised at how interesting it was. Good job. Found it very useful.
Glad you enjoyed!
All you need for zener diode training. As an added "free"bonus, I got to learn about curve tracers too. All in the time it takes to eat lunch.
Your videos are making me more and more curious about tubes. Another nice video, thanks.
+pkplex
Great to read!
Howdy! Thanks for the wonderful explanation. I received a MASSIVE, well for me anyhow, misc, sort of grab box filled from top to bottom with loose components. Thousands of resistors, hundreds of diodes and dozens of other components, capacitors and many that I cannot even identify, I believe go back to the days of the Automatic Electric Step in house telephone switching system. Now my old eyes aren't what they used to be, so I hooked up my cheap little microscope so I could read the codes on the tiny glass diodes and such. It has taken me three solid days just to separate the devices into categorize, and now that I have that sort done, I plan to sort the diodes into four basic groups. Rectifiers, High Speed Switching, Zener, and Shotkey. This video goes a long way into understanding why these are needed. I got the stuff from the Electronic Goldmine in Arizona. The parts are ALL top grade devices, none of the chinese clone crap, just sorting them made me feel a bit upgraded from circuit hack to perhaps a circuit builder.
Great video. The regulator tube is worked very accurately. Please give the part no for low voltage cold cathode regulator tube such as 12v.
maaaate that was an awesome show-down. the tube was solid as. had no idea they were that robust
Thanks again Mr Carlson I really appreciate you taking your time teaching electronics. Again cant wait till next week.
+Scott Lundy
Your welcome Scott!
I knew about Zeners, but the tubes are a new to me (eventhough they are old). Thanks!
+AsianTankPilot
Your welcome!
Recently, tubes have been getting hot.
Tubes are pretty.
@@whatsascrewdriver5572 Tubes have always gotten hot.
@@gyrgrls bah dum tshhh
OC3 is a very popular gas tube regulator...They're used in may Leslie Speaker Amplifiers. I've never seen one go bad...:) Great video...
+Frank Ferraro
I have rarely seen a failed cold cathode tube myself. Thanks for your comment!
Thank you, I really liked your spot-on explanation. Please explain more of the basics and the intermediary stuff!
+Josef Seibl
I definitely plan on it. Thanks for your comment!
In my tech school in the early 70s we mostly studied solid state circuitry and didn't dwell on tube theory as much but when I
graduated and got into servicing tube equipment I learned there was a lot of difference with the pros and cons of each.
High powered RF applications deployed a lot of tube circuitry and were pretty durable and in a lot of ways were preferred
over solid state PA circuits. The ole tube was more forgiving with high SWR versus the solid state RF amps. :)
+Dennis Petersen
This is why microwave ovens don't have transistors doing the work. Transistors are very sensitive to load and impedance variations. SWR (Standing Wave Ratio) is a real issue with transistors, where tubes are much more tolerant. Thanks for your comment Dennis!
Paul, You make electronics simple and interesting. I wish I had you for a teacher way back when I was in Electronics Technology school. I am in awe of your knowledge and your talent for explaining things. Thank you, Thank you, Thank you. John K4AGO
You're Welcome John! I'm glad your enjoying the video's.
Real good review for me on the zener diodes and you might say that tubes are hard to beat in many applications. The tube
has it's own temperature control built in much like a crystal oven for precise frequency control. :) Many thanks for showing
the video review!
+Dennis Petersen
Your welcome Dennis!
You are talking about current 'going across' and voltage 'going through'. A very interesting video but the switching around of voltage and current could be confusing. Still very interesting and worth a thumbs up.
+mbaker335
Thanks for your comment.
I would love to see you do a video on Glow Thyratrons, I've always found them interesting and they have a lot of uses
+Nexfero
I Have thought of making a vacuum tube SMPS with them. I have many 2050's
Again, absolutely love your video's. I like how you explain the theory and provide examples right away.
+SublimatedIce
Glad your enjoying!
OD3s have a beautiful neon Purple glow, IMHO. I understand the OA2s have some light sensitivity that can effect their performance, but I'm not sure how that works. I would love to see you explain the details of the different gas tube regulators!
Thx sir, please make a video about oscilloscopes operating for beginners , thx .
+Abdulkader Maqsoud
Thanks for your input!
Thank you very much Paul. I very always look forward to your videos.
All my very best.
Bobby
+Bobby Tectalabyss
Your welcome Bobby!
Thanks for the excellent video, Paul. I particularly enjoyed the 5651 demo.
+Shaun Merrigan
Glad you enjoyed Shaun!
Your curve tracer circuit gives that old EICO a new purpose in life. Nice!
+TerminalJack505
Old scopes need love too :^)
Nice lesson Paul, thanks. I really enjoy the Tech Tips Tuesdays.
+Robert Calk Jr.
Glad your enjoying Robert!
Clear explanations !
The test with tube ... amazing how much it stable.
That's explain why they still using tubes for some special tasks( I think )
+Mathieu Grenier
Thanks for your comment Mathieu!
Awesome ,seeing the tube takes me back to school when I was given a tube and you have to look in the tube to identify the heating element pin ,the anode ,the cathode , the grid ,the screen grid the control grid depending on the tube given ,awesome on explaining the use of a Zener diode , love it lol I need more
+danny blackhorse
This tube my throw you for a loop though.... it has no filament :^)
You ought to design a Carlson audio amplifier. You are a genius!
I had no idea the tube would be so accurate! Great video as always. Thanks!
Thanks - really enjoy your tech tips and longer videos! Your curve tracer is awesome. I built one but it's external to my scope and doesn't have the capability you've designed into yours. I'd be really interested to see more on this. Anyway, thanks again!
+Clayton Keltto
Your welcome Clayton!
Great video, Mr. Carlson. Much appreciated.
Glad you enjoyed Andrew!
I like to draw the "whisks" of the zener at 45 degree angle and make them pretty long, this makes it easier to read and distinguishes better from a Shottky symbol.
Great video and detailed explanation. Please make more videos on components. Many thanks.
Awesome. All your videos always make me encouraged to study more and more. Thanks for the good explanation and I appreciate.
+bee kay song
Glad these video's encourage you!
So how do they manufacture a 5651 tube with such accuracy. That accuracy has to be based entirely on the composition of the internal gas is it not? Is it "tweeked" before sealing off the tube? I really enjoy your showing comparisons between solid state and vacuum tube circuits. It makes understanding of the solid state bits a little more clearer.
+hankus253
They had lost of tricks up their sleeves back in the day. The accuracy involved in building a tube, and the consistency in the resultant final test readings is often better then their solid state counterparts. Many of these tubes ended up in military electronics way back when.
Very interesting about the vacuum tube verses the zener diode unfortunatly I missed the valve era by maybe a decade being old enough to understand the theroy of the vacuum tube. I remember my father building a 2 meter valve transmitter and his all valve SSB phaseing exciter for HF he still uses his valve linear with his Kenwood TS120V. I thought the zener would be more stable than the valve voltage regulator but the opposite seems to be true. Thanks again for your time and effort.
Regards David Grey By the way the linear uses a pair of 807's still going strong from the 70's.
+David Grey
Thanks for your kind comment David!
Very cool to see the tube beat silicon at the end. It would be neat to see the curve trace of the tube diode. I’m not guessing 85 volt curve tracers are very common though haha
Very informative. Thanks for teaching me. I never knew about Zener diodes before.
+Timothy Preseau
Your welcome Timothy!
I stumbled on to your channel. I like how your methods of teaching as in a clear explanation & then a demonstration. But I do have one question. Why do you use the Conventional flow instead of the Electron flow for your teachings?
Actually, I switch back and forth. I use what ever makes understanding the subject at hand easier.
I wish we could all go back to valve/tube electronics. Those were the days of true engineering.
Thanks for doing these excellent videos. it would also be instructive to include a comparison of the tube VS zener with regard to load current fluctuations and supply voltage fluctuations.
+Stanley Chytla
Thanks for your input Stanley!
Great job on your video I really learn a lot I enjoy learning new things about circuits keep up the great work
+K4TEP
Thanks! Glad your enjoying.
Mr Carlson your videos are wicked..very well explained!
Thanks Paul, very interesting. Regards Bob
+Bob Mellor
Glad you enjoyed Bob!
+Mr Carlson's Lab I just love the way you do videos.You never assume that every one already is advanced electronics. I have learned more hear then all the books and math that I learned in school.I first really got interested in electronics when I had to pass a general class amateur radio test years ago . I think I'm going to get back to basics in stead of just being a appliance operator .Thank you Paul.
Thanks for the kind words Ashley! Glad your enjoying the video's. Your very welcome!
I am fixing tube amplifier for many years, modern amplifier like Audio Research use all the rectifier section and regulation with solid state components and the audio path with vacuum tubes.
Cheers.
My homebrew 80 through 10 Meter CW Transmitter uses 2 OB2s in series to regulate the plate voltage of my 6146B final.
Hi Paul, I don't usually write a comment to any of your video's as their context is beyond my scope of understanding. (especially RF tuning and aligning) However, I do thoroughly enjoy watching the resurrection and restoration of the vintage equipment you repair (sometimes brilliantly incorporating modern components to do so). I also eagerly await new Tech Tip Tuesday uploads as one would watch a favorite TV show ;) I wanted to ask if perhaps you could make a video explaining the differences between Class A, B, A/B, and C amplifier designs? And SET and PP and their relationship to the different classes? I hear a lot of mixed up explanations on the web, which just adds to my confusion (and most likely others) on the subject. I know it's a big undertaking and a lot to ask for, but as is said, the squeaky wheel gets the grease and if you don't ask it will never happen. I will understand if you are too busy with other projects and subjects, and don't have the time to do so. Either way keep up the great video's and topics and I will continue to watch. Thanks, Tom
+Bucyrus Erie12
Hi Tom. I will put that on my "to do" list. I have a video coming shortly, hopefully up this weekend. Glad your enjoying the video's, and thanks for the kind words too!
Great topic and nice demonstration
.
I didn't really know that much about diodes. Very informative, thanks.
+jim mcdowell
Glad you enjoyed Jim!
29:00 Hi Mr. Carlson, just curious and concerned that you aren't too worried working with 85VDC where anything over 30VDC is considered lethal/hazardous; sure, your current draw is ~4.5mA but isn't this still dangerous?
Very interesting and concise demonstration and explanation ,thankyou.
Very good explanation and a great review
+James Silberman
Thanks!
Great way of explaining the behaviour of diodes by using the one way valves analogy, I'll use it myself with your permission ;-)
+Ignacio Simón
Glad you enjoyed Ignacio!
Hi Mr.Carlson my name is Luc and I really enjoy your videos.I was wondering if you would like to show us how you do a test on a vacuum tube amplifier to check for distortions and the way you would go about fixing the problem.And if your up for it you could include a tutorial on how to set up your equipment before you do the actual testing on this amplifier.
+lucancherby
I will do a video on this in the future. Thanks for your input.
Always something more to learn.. Thank You Paul
No Problem Wayne. Glad you enjoyed!
Thanks for the video. Would like to see other video's of circuit "building blocks". Eg CCS, oscillators, RC filters, LTP, cathode follower etc. A few formulae would be good too.
Also VERY interested to see your circuit/build of the Eico scope curve tracer.
+Dr Wobble
Thanks for your input! I will put that on my "to do" list.
Could you do a tech video on Darlington transistors....
I never quite understood thier purposes...Tho we saw them often in older TV's, didn't see many later on.
Also, shottky diode.
Thank you Paul.🙂
Great video Mr Carlson. Thank you !!
Glad you enjoyed!
As usual very informative , thanks Paul .. keep 'em coming ;)
+Qasim Seeha
Thanks Qasim! I will definitely try.
Keep 'em coming. Just a member of your audience.
that OKs and all rights were little irritating other than that awesome explanation bro pls continue the good work