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
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.
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.
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!
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.
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!
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
+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.
Wow, I learn so much watching your videos. Thank you for taking the time to share your knowledge and techniques. Your test equipment is off the charts!!
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.
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.
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.
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.
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
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.
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.
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.
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.!
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
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 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.
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.
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.
+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.
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!
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.
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.
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!
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 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
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!
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.
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.
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 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.
