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!!

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.

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.

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.

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.

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!

So old school tubes are more stable than solid state parts, amazing. Great job schooling us ol' hacks, thanks for teaching us all.

"Here's a curve tracer I quickly knocked up one day... with screensaver" :D

Thanks Mr. Carlson , you're a gifted instructor , easy to follow .

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.

Thanks for keeping your youtube classes online for so long.

A diode that's massively overloaded becomes (momentarily) an SED (smoke emitting diode)

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.

Really terrific session. Love that Heathkit voltmeter with the Nixie display. I am a lifelong Heathkit builder and now collector. A true Heathkitnic.

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.

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!

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!!

Your videos are extremely informative and very well done. Thanks for putting so much time and hard work into it

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.

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.

Your videos are making me more and more curious about tubes. Another nice video, thanks.

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 had no idea the tube would be so accurate! Great video as always. Thanks!

I wish we could all go back to valve/tube electronics. Those were the days of true engineering.

Nice video for a refresher for my 70 yr old mind thanks Paul

Again, absolutely love your video's. I like how you explain the theory and provide examples right away.

Thanks, Paul. It's always nice to have refresher courses on components.

Thank You, Thank You, Thank You. 'Dumbing' it down to a level that I understand... Your a great teacher and your visuals are excellent.

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

Thanks again Mr Carlson I really appreciate you taking your time teaching electronics. Again cant wait till next week.

A very good and precise explanation. Well done as always.

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.

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

Your curve tracer circuit gives that old EICO a new purpose in life. Nice!

the tube never gets under 85...amazing, and much more beautifull aswell 😆

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.

I didn't really know that much about diodes. Very informative, thanks.

Thank you very much Paul. I very always look forward to your videos. All my very best. Bobby

Awesome. All your videos always make me encouraged to study more and more. Thanks for the good explanation and I appreciate.

Great video, Mr. Carlson. Much appreciated.

Mr Carlson your videos are wicked..very well explained!

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.

Thanks for the excellent video, Paul. I particularly enjoyed the 5651 demo.

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.

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.!

Very informative. Thanks for teaching me. I never knew about Zener diodes before.

Nice lesson Paul, thanks. I really enjoy the Tech Tips Tuesdays.

Great video! ive learned so much. I never knew VR tubes were so accurate. can't wait for more of these informative videos

Thank you, I really liked your spot-on explanation. Please explain more of the basics and the intermediary stuff!

Great job on your video I really learn a lot I enjoy learning new things about circuits keep up the great work

Always something more to learn.. Thank You Paul

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.

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

Great topic and nice demonstration .

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.

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.

Best short video ever. Thanks! And your Patreon subscription is worth every penny.

maaaate that was an awesome show-down. the tube was solid as. had no idea they were that robust

Another excellent starter tutorial! Take care

Thanks again and of course another awesome video loaded with info explained very well for us slow to get it guys.

Great video and detailed explanation. Please make more videos on components. Many thanks.

As usual very informative , thanks Paul .. keep 'em coming ;)

Great video Mr Carlson. Thank you !!

Very interesting and concise demonstration and explanation ,thankyou.

Always thank you for uploading video! your lecture is easy to understand

Keep 'em coming. Just a member of your audience.

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.

Flawless as usual. Thank you sir.

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

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.

wow! I alwaYslove your stuff. You do great teachingv work...so clear and helpful!

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

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

another masterclass very good job

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. :)

Fantastic review

be cool to hear that 1 hour discussion of the full details of that circuit!

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 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 - 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!

Just love your videos!

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.

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...

Great video. Thank you.

Very good explanation and a great review

Very Interesting, Great Video! Thank You!

Very good teacher..... Thanks Paul :)

Thanks! This showed me how I can solve an issue I have with supplying both 12 and 5 V :-)

The amount of aha moments I have while watching this just makes me smile

I knew about Zeners, but the tubes are a new to me (eventhough they are old). Thanks!

Excellent again.

Great instruction, keep it up!

fantastic video, thank you for sharing.

excellent as always Paul.

Great way of explaining the behaviour of diodes by using the one way valves analogy, I'll use it myself with your permission ;-)

Theory is great, but knowing how things work in the real world is really useful.

GREAT VIDEO! Thank you!

Best explanation ever💯💯💯

Great job as usual! Thanks.