*Some of you have advised against putting an oscilloscope on an isolation transformer. The main reason is that by "floating" your scope with respect to earth, the outer conductor of the BNCs also float and can therefore rise to dangerous voltages due to probing. This is good advice and safety measure. Always place the DUT on the isolation transformer and never the instrument! This is how all my setups are done.*
@christophscholz3 жыл бұрын
Or use a memory recorder. Memory recorders have isolated inputs.
@NiHaoMike643 жыл бұрын
Or use isolated probes, but those aren't cheap. Probably the cheapest but safe solution for hobbyists is to use an inverter powered by an isolated DC source.
@DmitryOrlov_dimorlus3 жыл бұрын
I use two isolating transformers, one for DUT and another one for instruments.
@christophscholz3 жыл бұрын
@@DmitryOrlov_dimorlus that is certainly possible. Get the right tool for the job! Or as my friend Ed always said: ‘because you could doesn’t mean you should’
@DmitryOrlov_dimorlus3 жыл бұрын
@@NiHaoMike64 Transformer is much chipper and reliable, and doesn't create noise (EMI).
@MIsam-fv9kb3 жыл бұрын
The quality of content in the signal path is unmatchable.
@supercompooper3 жыл бұрын
The signal to noise ratio is excellent!
@garybevis86913 жыл бұрын
You are an inspiration for so many. Thank you Shahriar, I love you and your work, so glad I found you years ago.
@Thesignalpath3 жыл бұрын
Thank you!
@mikeselectricstuff3 жыл бұрын
Startup caps on a SMPS are such a common failure that I just replace them first without doing any further tests. The classic symptom is a device that was working, but then failing to come on again after power has been removed.
@WizardTim3 жыл бұрын
I see this failure mode all the time as well, although I often find a design will splurge on a name brand 400 V bulk filter capacitor, but the bootstrap capacitor will be some Dongguan back alley special in the smallest and highest ESR package they can find (much smaller than the ones in this video). Makes me rethink where I should be spending my BOM.
@HenkAlles2 жыл бұрын
The reason the startup cap has such a high voltage rating is that if the power supply doesn't start for any reason/fault the voltage in the cap can go way higher that 50V
@morbos3 жыл бұрын
Wow! A miniature F-P! We had a bench sized one in the mid 80s for Alexandrite work. This is mind blowing.
@Gabriel-kz8ns3 жыл бұрын
"Jump to 9:30 if you like to skip the repair" why on earth would someone wanted to do that? Amazing as always, specially the smps caps... hey! that's something i do! you know... not everyone own an xray machine....lol Greetings from Argentina!
@HuygensOptics3 жыл бұрын
Very nice, I love it when you do these optical subjects! The substrate that the tunable laser diode was mounted on looked like something special, maybe Zerodur or some other low CTE glass-ceramic material?
@heinrichhein26053 жыл бұрын
Looks like AIN to me
@enclis3 жыл бұрын
AlN is quite common for these types of applications. You can find it almost in every mass product butterfly-like assemblies. Zerodur will be overkill.
@heinrichhein26053 жыл бұрын
@@enclis yes also from the color, an i think it is hard on other material to make solder contact surfaces that hold well. Zerodur is way too expensive ^^
@ligius33 жыл бұрын
This video was all over the place, in the best way possible. I think the only thing missing from this channel is something with magnets, like a MOT.
@kcmichaelm3 жыл бұрын
In a previous career I serviced and supported commercial laser printers. In a consumer or midrange printer, the laser is a sealed unit which is not serviced. In the highest-speed printing environments, they were made with 15-50mW gas lasers (usually argon), or with laser diodes. This video covered so much of the similar technologies. The components in these types of laser arrays would all be replaceable and adjustable, much larger than a sealed wire-bonded unit. I miss the art and science of adjusting those units. Such happy memories :)
@thomasklima2153 жыл бұрын
Great video, thanks! I actually laughed out loud seeing the values for the second start up capacitor xD
@AndyFletcherX313 жыл бұрын
Very interesting breakdown of how tunable lasers work. This is what KZbin should be about. Thanks
@esepecesito3 жыл бұрын
I loved the fact that the last instrument was based in another measuring method, so we learned still something different. So much information in one video! Just great! Make more like this!
@ef74083 жыл бұрын
Out standing content here. Greetings from France.
@erikisberg38866 ай бұрын
Found Your excellent channel just recently, subscribed! I am an EE running my own lab as well, mostly worked in analog development projects as a consultant and in startups. Way back a 1/4 century ago me and several of my friends did work for a small company in Gothemburg, Sweden named Radians Inova AB. The the flagship was a then state of the art tunable laser. The company was subsequently sold to Thorlabs and in 2009 the project moved to the US. If I remember correctly HP was the main competitor back then. I have a controller and some laser heads, have to dig them out end see if it is possible to do something interesting... Thanks for a very interesting video!
@PushyPawn2 жыл бұрын
Until today I had no idea you could make a tuneable laser source of such precision. Amazing.
@jaro69853 жыл бұрын
Good video as always, somehow it seems you are getting even better and concise at explaining all of these concepts.
@topphemlig11913 жыл бұрын
Wow things I studied right there on the bench. Fantastic channel
@stevenbacon38783 жыл бұрын
Great video as always, I really enjoyed the experiments and teaching!
@hommadi20013 жыл бұрын
Always enjoy your videos. I work in a synchrotron facility building and testing undulator magnets, which ARE the ultimate laser sources producing kWs of coherent X-ray beams.
@xDevscom_EE3 жыл бұрын
@The Signal Path we should do quantum metrology video ;-)
@Thesignalpath3 жыл бұрын
That would be very interesting. I hope we can find the time!
@jasonhermanus53683 жыл бұрын
Awesome! Thanks Shahriar
@TimLF3 жыл бұрын
Thanks for the amazing videos. Obviously laser cooling is cooler than laser hammers...
@trickyrat4833 жыл бұрын
Fabulous video. Many thanks.
@Bluebirdiran2 жыл бұрын
دست شما درد نکنه جناب نابغه قرن. خدا حفظتون کنه.
@aeonikus12 жыл бұрын
Amazing knowledge and well put in understandable manner. Thank you for the effort. Keep them coming! :)
@TeslaTales593 жыл бұрын
Nice repair and discussion
@andymouse3 жыл бұрын
Fascinating tutorial....cheers.
@Mr1Spring3 жыл бұрын
Very nice and I liked the detour to the Linksquare thingy. Perhaps a new video about that?
@benmodel57453 жыл бұрын
Out of curiosity, how much current did that diode take? Are these systems relatively efficient?
@Thesignalpath3 жыл бұрын
At 50mA it was putting out about -3dBm.
@thomasw61693 жыл бұрын
Every time I start watching one of Shariar's videos, I wonder what will the fault be today ? Fuse or just a connector come off 😀 Hey! Not so easy this time...
@Xaerorazor03 жыл бұрын
We have on campus a monochromator, which uses 2 Diffraction gratings in series, which was used with a non-coherent light source of high intensity which was then passed through an unknown color filter, and it was set up to scan through from Mid IR to UVA to a sensitive optical sensor that measured power and we got a characteristic curve showing the band pass of the filter. It was also used to test CCDs, CMOS, and and other photo detectors and check their photon conversion based on wavelength.
@WizardTim3 жыл бұрын
The shiny bare machined optical enclosure of the Agilent multi-wavelength meter makes me uncomfortable! But I do see this somewhat often in certain optical test instruments, I would have thought you'd always want it matt black? From what I understand the geometry of the Michelson interferometer doesn't inherently reject dynamic scatted light, I would assume it would just raise the noise floor?
@RyanUptonInnovator3 жыл бұрын
Great video. I would like to to see some more videos about magnetic levitation.
@mikeselectricstuff3 жыл бұрын
Such a shame they don't make visible light tuneable lasers
@enclis3 жыл бұрын
There are a lot of visible light tunable lasers on the market. If you meant Santec only, it turns out that relatively low power visible light CW+external modulation (not pico/femto-, supercontinuum like, etc) tunable lasers that are probably can be done by Santec is not that of an interest for the market. We have a lot of cheap mass-product fiber coupled NIR tunable lasers due to telecom WDM systems.
@LesLaboratory3 жыл бұрын
If you have the money: www.newport.com/mam/celum/celum_assets/resources/Vantage7100_datasheet.pdf?1 Tuning ranges are quite narrow though.
@enclis3 жыл бұрын
@@LesLaboratory Or you can just take supercontinuum source ( www.yslphotonics.com/Home/Index/Product/details/id/50.html ) and filter out almost any frequency you want from 410nm to 2400nm
@PaulHigginbothamSr3 жыл бұрын
Was wondering about the Pico wavelength pizo-chrystal controlled laser. Does it turn the mirror slanting or the spacing of the incident light dots?
@jj74qformerlyjailbreak32 жыл бұрын
I want to capture still shots of the J 11 process delided! what would you suggest for capturing the images? What camera are you using? And yes that’s the best sight all day. Nice and mate black/gold 👍 God Bless.
@joopterwijn3 жыл бұрын
@01:25 into the video,…. With your luck, it is connecting cable, fuse or 😂
@campbellmorrison85403 жыл бұрын
Quite increadable. How on earth would you make the parts that are on this assembly let alone actually assemble and align them. And for peanuts! Stunning stuff
@wadehsu23473 жыл бұрын
I have never heard of using laser to punch the components into position in photonics and micro-optics packaging. I can imaging there are several reasons not to do that. One would be the power required and the debris generated during the process would be very bad for those free space optics. Do you have any references on how this is done? Single mode fiber coupling in integrated optics package are typically done with nano positioning stages during glueing. Fiber coupling are sensitive, but not that sensitive. You can be off by a um and still have acceptable coupling efficiency.
@lelsewherelelsewhere94353 жыл бұрын
Great video! Do you know of any devices that utilize the magneto optical Kerr effect, or (maybe entering rf territory) evanescent waves to do calibration (or for any other reasons)? I think any device utilizing those would be fascinating to look into!
@tonybell15973 жыл бұрын
Many thanks for this, Ive been using Sm Fibre in my work, and never really understood it ("All Smoke and Mirrors..." is the usual description....... fantastic insight....
@dtiydr3 жыл бұрын
This was so interesting! Thanks!
@egbertgroot27373 жыл бұрын
Very good content !!!!!!
@MIsam-fv9kb3 жыл бұрын
Woooooow I learned a lot of new stuff This episode was great .
@simonmay90393 жыл бұрын
Curious about how the LD will somehow synchronise with the frequency of light reflected back into it.
@freewilliTV2 жыл бұрын
This is due to a phenomenon called stimulated emission. It is the fundamental thing that makes lasers work and produce coherent radiation. Basically, a photon that is reflected back into the LD will stimulate the recombination of electrons and holes inside the LD. The photons emitted in the recombination are in phase and of the same wavelength as that original photon, and they stimulate further recombination and so on. Eventually, the large majority of the photons are produced this way and you get laser light.
@seanblakley21923 жыл бұрын
Those old HeNe lasers stop working after a while because their gas tube fails and needs to be replaced. This is true of all gas lasers, which is why most instruments now use diode or other solid state laser technologies. If it is indeed the gas tube that has failed in that laser, it might be difficult to source a compatible one that still works.
@kcmichaelm3 жыл бұрын
Yep. Our applications of gas lasers would have a simple ammeter on the driver input. Once the gas started to get very low, you’d see a high draw of current and know it was soon to fail. In our case, we went through hundreds of the exact same unit, so the OEM would remanufacture them - however the reman units had a substantially shorter life.
@wadehsu23473 жыл бұрын
Most wavemeters nowadays still use HeNe lasers because a stabilized HeNe laser has a relatively precise absolute wavelength to ~ppm level. Most solid state laser are not absolute and can vary up to several nm so it’s easier to use a HeNe as a light source so the instrument doesn’t need to be designed to accommodate calibration over several nm.
@dtiydr3 жыл бұрын
@@wadehsu2347 Solid states laser can be made as frequency stable as HeNe lasers, but those are extremely expensive and HeNe lasers also have very tight beam that is hard to get on solid state lasers. So thus its way cheaper to get a HeNe laser which it very stable as is, only disadvantage is that is bulky and need HV but they can be made quite small if not need any real power from them.
@wadehsu23473 жыл бұрын
dtiydr yes, solid state laser can be frequency stable, but they are not inherently accurate and not as stable as stabilized HeNe laser. So each laser will need to be measured and calibrated and the range of that calibration can vary up to 10nm. Unless the laser diode are lock to an atomic reference then the accuracy becomes absolute, but that come with a price of complexity and wavelength typically in the IR for common atomic reference such as Cs or Rb. Also, long term stability of single frequency diode laser are poor if not locked and they are also temperature sensitive. So to maintain the wavelength stability the temperature and current of the laser diode will need to be regulated to better than 1mK and ppm stability.
@dtiydr3 жыл бұрын
@@wadehsu2347 All correct and thus their price and in many case a HeNe is easier to control that part but not as wide band and also bulkier which could be a constrain sometimes but otherwise its pretty much the best choice and no doubt cheapest.
@Manawyrm3 жыл бұрын
This was highly interesting. I kinda want to build my own crude tunable diode laser with closed-loop feedback now. **hm**
@jjoonathan71783 жыл бұрын
Maan we need to figure out an excuse to get more spinning things in RF equipment.
@Thesignalpath3 жыл бұрын
We make phased arrays to not have to do that! ;)
@alimonemdjou4733 жыл бұрын
درود... بسیار لذت بردم
@Kosmonooit3 жыл бұрын
This had me thinking of Newton's famous prism experiment.
@johnshaw3593 жыл бұрын
There was something that you either took apart or repaired a few tears ago that had a spinning light wheel. Can you remember what it was?
@Thesignalpath3 жыл бұрын
Yes, it was a wavelength meter as well.
@stevefriedl39833 жыл бұрын
It was TSP#29, Teardown, Repair and Experiments of an Agilent 86120B Multi-Wavelength Meter kzbin.info/www/bejne/rYm5fHuCjbRgptE
@douro203 жыл бұрын
Does that power synthesizer support 400Hz output? Yes I'm calling it a power synthesizer because that is basically what it is.
@stargazer76443 жыл бұрын
It is a power supply, and the output is DC. The transformer runs far higher than 400Hz, usually in the hundreds of kHz or even MHz.
@PaulHigginbothamSr3 жыл бұрын
I was trying to see how an optical silicon microprocessor could use the frequency deviations for mathematical functions especially in a Pico wavelength measure. I can see how it would be faster than electrons because it could be instantly read globally on the face at a moment.
@tommihommi13 жыл бұрын
wait, the way diffraction grates split one laser into multiple dots is the same mathematics that causes grating lobes in an antenna array, right? That's where the name comes from?
@combin8or3 жыл бұрын
Ok I’ll bite. If you want intuition about optics (and laser phenomena), watch @Huygens Optics videos about photon sieves (essentially phonon ring resonator interactions). A collaboration between you two would be fascinating.
@roybrown49443 жыл бұрын
Beautiful
@wawakgdn3 жыл бұрын
I think I am first :D Time to watch the video ;-) Edit: As always I enjoyed the repair part. I am not much into RF or optical stuff, but I can learn a lot from Your videos. Keep it up!
@danmenes31433 жыл бұрын
I appear to be second. Where's the party?
@ceevenson3 жыл бұрын
3
@jjoonathan71783 жыл бұрын
I sprayed cold air on my DS1054Z but it didn't go to 100GHz... halp?
@SaNjA26593 жыл бұрын
7:12 It'll blow up your scope even if you probe the negative pin of that capacitor, or in fact any pin after the rectifier. Because of the way full bridge rectifiers work, both DC rails end up floating around with amplitude of the mains Vpk.
@trevorjayman43643 жыл бұрын
Dude... like how many branches of engineering are you an expert of?! this is getting depressing for me...
@wilmhit3 жыл бұрын
Do you have channel on Odysee?
@gordonwedman31793 жыл бұрын
Interesting video. Another expensive piece of equipment rendered inoperable by a few dollars worth of capacitors. I think l know what is causing the Hubble grief....
@glasslinger3 жыл бұрын
Also interesting that some agency (government funded lab or possibly college lab) disposed of an instrument that any reasonably experienced tech could have easily repaired. Hey, the taxpayers have endless amounts of cash available!
@istvanbakronagy30353 жыл бұрын
20:32 ... and imagine all those discrete optical parts integrated like transistors in a chip, then you would get a PIC like this: effectphotonics.com/nasa-acknowledges-effect-photonics-pic-as-a-state-of-art-commercial-example/
@gacherumburu99582 жыл бұрын
👍👍
@bluetrepidation3 жыл бұрын
I have the same DMM.
@Thesignalpath3 жыл бұрын
Which DMM are you referring to?
@bluetrepidation3 жыл бұрын
@@Thesignalpath Keysight U1282A 😁
@der.Schtefan2 жыл бұрын
You. You are cooler than this! ;)
@heinrichhein26053 жыл бұрын
I have noticed you often use the term calibration a bit wrong, instead you should say adjustment. By definition, you don't adjust or change an instrument during a calibration, you just verify that it is still in spec. Only a small amount of Equipment get adjustments over their lifetime. So the outcome is either yes or no, and if no it might be possible to do an adjustment/alignment. I know you know this, but I find it important to do it Right, especially because you are teaching and have a lot of reach. I also know this misconception is wildly spread but important to get Right, I would hope you can integrate this. Thanks for the good videos.
@Thesignalpath3 жыл бұрын
Thanks for the point. I am not sure if I agree with it. The term _calibration_ in this industry has a well-defined meaning. The calibration process ensures that the instrument produces or measures the desired parameters based on its specifications. The calibration process achieves this by either making adjustments to the unit or by applying appropriate offsets, lookup tables, etc. in software. Regardless on how it is done, this process is called calibration for test & measurements instruments. If you ask me _how_ calibration is performed on a _specific_ instrument, then I can describe whether it is done by adjustment, or otherwise.
@heinrichhein26053 жыл бұрын
@@Thesignalpath yes I agree in the industry it is quite common to say calibration to both. I even noticed when I was younger I often heard it and though calibration also meant adjustment in the equipment, but I learned only later that people often used it that way. And I think even a lot of technical people who are not directly involved with calibration of Equipment probably think that they get adjusted when they get calibrated, but that's rarely the case. For most industries, at least. I also agree that we use the term as a whole of the process, but by definition an adjustment can be only a subsequent result from a Calibration result. As also NIST Handbook defines, "Strictly speaking, the term "calibration" means just the act of comparison and does not include any subsequent adjustment.". But yes, I'm splitting hairs, maybe. Also, it is not difficult or even hard to change the usage. Would be interesting to ask engineers but also hobbyist, I think you would be surprised on how many don't know what happens when an instrument gets calibrated, maybe that would be a video idea, also if possible with a cal lab as a cooperation.
@stargazer76443 жыл бұрын
The calibration chapter in every device's service manual ever printed disagrees with you.
@heinrichhein26053 жыл бұрын
@@stargazer7644 does not mean it is correct Nist and the German PTB see it the same way i do it, i also quoted it before. i think if PTB does say it so i would think they have a point. you will also see if you buy a calibration service you won't get a adjustment you have to buy a adjustment separately form every service provider, proving the point further
@stargazer76443 жыл бұрын
@@heinrichhein2605 Well, how about checking a dictionary? According to Merriam Webster, one definition of calibrate is to measure precisely against a standard. That's the sense you're using it in. Another definition of calibrate is "to adjust precisely for a particular function". That's the sense we're using it in.
@thomasw61693 жыл бұрын
7:07 please do not suggest to put the oscilloscope on the isolation transformer. That's dangerous.
@digitalradiohacker3 жыл бұрын
As the immortal Q mused to Picard: "If you can't take a little bloody nose, maybe you ought to go back home and crawl under your bed?" He went on to warn that: "It's not safe out here. It's wondrous, with treasures to satiate desires both subtle and gross - but it's NOT for the timid".
@thomasw61693 жыл бұрын
Said this because he's immortal, right ?
@Thesignalpath3 жыл бұрын
@@thomasw6169 Thanks, I added a pinned comment about this. And yes, I am also immortal.
@thomasw61693 жыл бұрын
@@Thesignalpath Haha, right. And it's easily forgotten during work that the whole case (if metal) can become live depending on how you connect your probe ☠️
@tommihommi13 жыл бұрын
I think you should have mentioned to NEVER use a isolation transformer for the oscilloscope. If you do that, and then connect the probe ground to a high voltage relative to ground, all the BNCs on the scope along with parts of it's case suddenly are dangerous.
@Thesignalpath3 жыл бұрын
Thanks, I added a pinned comment about this.
@mlefe093 жыл бұрын
Loved this, lots of explanations and details: good job!