12:43 -- Jacobi did publish a picture of his rheostat in 1842: Jacobi, M.H. (1842) "Beschreibung eines verbesserten Voltagometers" (Description of an improved voltagometer) Bulletin Scientifique publié par l’Académie impériale des sciences de Saint-Pétersbourg, 10: columns 285-288. Three diagrams appear after column 288.
@@Kathy_Loves_Physics -- You're welcome. 🙂 If you want a translation of the article, I could provide one. (It would take a few days to type it up. And I'd need an e-mail address to which I could send it.)
Good find. However; he saw Wheatstone's rheostat in 1840, but not published his book until 1842, so why Kathy implied Wheatstone had seen Jacobi’s before 1840 (20:39) by repeating the quote “quite impossible” in the text? The whole sentence means otherwise.
@@htooloo365 -- Yes. At 8:28 the text of Jacobi's article states that Jacobi thought that Wheatstone could Not have known about Jacobi's rheostat when Wheatstone invented his own version of a rheostat. So in Jacobi's opinion, they had invented the rheostat independently. The text originally appeared on p. 21 of: Jacobi (1840) "On the principles of electro-mechanical machines" Tenth Meeting of the British Association for the Advancement of Science: Notices and Abstracts of Miscellaneous Communications to the Sections pp. 18-24.
When I was a kid, remember my physics teacher muttering darkly that "It isn't Wheastone's bridge, it's a Christie's bridge"...the text-books said otherwise. Thanks for clearing that up!!
Another home run! I would like to add as an aircraft technician, this concept is used to measure the density of the fuel by weight, using capacitors instead of resistors. The variable capacitance being the fuel compared to a known reference capacitance.
where can I read more about this in your application? I am a marine technician specializing in electronics, networks, and sensors... also working on my own engine instrumentation systems. thanks
Would be amazing to see film footage of these early "electronic" inventors at work in their laboratories, if only that was possible. Would be great to see close ups of them making all the inventions at the various stages.
The context you use to describe these basics of electricity and magnetism is most enlightening. As-in the true historical machinations and personalities behind these leap-frog discoveries. Thank you Kathy.
Thanks, never heard of Moritz von Jacobi before, but I did hear of use his Maximum power theorem. Basically always match impedances for maximum power transfer, it is one of those things that is as fundamental as ohms law and taken for granted. In the RF world most circuits are designed to have 50 ohms on their inputs (e.g. reference clocks) and outputs (e.g antennas). In designing high speed address and data buses in computers the impedance of all the transmission lines on the PCB's (Printed Circuit Boards) would all be designed to match the input and output of everything on the buses (e.g. memory, I/O and CPU) which is typically 50 to 60 ohms. I love your video as always! Thank you.
I was tempted to mention his maximum power equation but the video was already so long that I had to cut it. Jacobi deserves his own video honestly. Glad you liked this video and thanks for always commenting
More famous than Moritz probably is his brother Carl Gustav Jacob Jacobi (en.wikipedia.org/wiki/Carl_Gustav_Jacob_Jacobi) at least in mathematical circles.
As a former EE student, these names, these people are the Hallowed saints of electronics (Voltaire, Ohm, Wheatstone, etc). Thank you so much for bringing them to life, and for showing them to be human; warts, misrepresentations and all.
This is the first mention of the Wheatstone Bridge I've heard since I left Ma Bell many years ago. Years ago telephone central offices had a test desk. In most cases it looked like one of the old corded switchboards operators worked from. The test desk took trouble reports from customers, tested them, dispatched a technician if necessary and then closed the ticket after noting what had been done to clear the problem. Most of them have disappeared if not because most testing is now done in the field by the technicians and the whole process has become computerized. Every test desk had a Wheatstone Bridge mounted in a drawer. The test deskman (old terminology) used it to measure resistances on cable troubles using a Murray Test Or a Varley Test. A technician would call in and the testdesk using the cable plats send him to the farthest end of the cable and short circuit the pair of wires in trouble. The pair of wires would be connected to the bridge. If one side of the pair was grounded he would measure the resistance through the short circuit to ground. Then he'd reverse the bridge and look thought short in the other direction. Using a math formula and consulting the cable plats showed the overall resistance and capacitance the cable he could put the technician within a few feet of the problem location. I the cable was running in the air the outside temperature was factored in. Buried cable was consistent in temperature. Mixed buried and aerial cable caused a fluctuation in the math but a good test desk man could still get you very close. At the time which was before the 1970s all the test deskmen were cable repairmen and a few equipment technicians tired of working outside in the weather. Some of the equipment technicians would transfer into the central office as Switchmen. That all changed in 1970 when the company women in these technical position to satisfy the Equal Employment Opportunity Commission. Without the field experience most of the women did the testing poorly. for the women it was all about money. The technical positions were filled with men and they paid better than the mostly clerical positions women were in. Almost immediately the company developed computerized testing. Once it had saturated the system almost all the testdesk personnel were downgraded to a clerical position that paid less and required less skill. The line cards were removed and the records were computerized. In an entire region there were one or two testdesk technicians and his testdesk used trunks to test in any troubles for the entire region. The Wheatstone Bridges. Eventually the Wheatstone Bridges disappeared. So did almost all of the technicians. The system is so computerized that people with those skills are no longer needed. That and the reduction of telephone lines on copper. Computers now compress thousands of telephones on what once could only carry one. Now you can get your telephone on a coax cable carrying your television signal and Internet service. Or you can just use a cellphone with a satellite dish for television. The installers now using technician as a title are installers. They have so little knowledge of equipment and electronics they are not technicians in reality The Wheatstone Bridge left with the technicians and they aren't coming back.
@@gpwgpw555 Yeah, that was the old one. I would sometimes go inside to cover someone on vacation. We had a "temporary" test center using 2A cabinets. You must be another old timer. We're disappearing fast. It seems like someone passes every other month. And not very old either. The business really changed. The smaller COs have no one working in them. The cable techs make the inside connections, at least they used to until the SMAZ frames. Good Luck.
@@robertcuminale1212 42 years as a switchman in Oklahoma City. I loved 37 years of it. In the last five years we became customer driven. meaning we did not fix anything unless customers reported trouble.
Hey, Jacobi didn't write that it was impossible that they had come up with the same idea independently, he wrote that it was impossible that Wheatstone "should have had the least notice of my instrument", implying that he was convinced that they HAD come up with the same idea independently. Thanks for these videos!
And in the next sentence he praises Wheatstone for the wide variety of uses as a measuring tool that Wheatstone found for this device while himself only used it as a regulator. This is an extra argument for independent simultaneous discovery since they both created their device for different purposes.
@@christianbarnay2499 people at that time would choose politeness over direct confrontation to cope with public known figures stealing their ideas and decide to be the bigger person by attributing praise on the stealer not for stealing but in order to showing no hard feelings but they had internally recognised their own acheivements and felt it
@@kevindoom You can still politely criticize the attitude of someone, just like Cooke did when he clearly disapproved Wheatstone claiming their collaborative work as his own. When Jacobi says that Wheatstone and himself created the same instrument independently for different purposes (Jacobi needed a regulating device, Wheatstone needed a measuring device) there are no valid reasons to not believe him.
@@christianbarnay2499 whetstone was declaring that he independantly came up with it but in the exact same way the exact same way it was obvious of course Jacobi knew but he decided to deal with it politely
I worked in a research and testing facility for a few years. When checking some background information on strain gauge measurements (you should know some basics of what you do), I also got to know Wheatstone's bridge. The measuring amplifiers nowadays are quite easy, you click on a button in the software to set all strain gauges to zero before the measurement, but in "ancient" times so had to tune one of the resistors in the Wheatstone bridges for each individual strain gauge by hand to start the measurement at 0 (or whatever value you liked).
New follower here... I've worked in electronics most of my life and understand it as well as the next guy... I guess, but I've only known little snatches here and there of the history behind it all. I love your videos. Gets me closer to something I've always taken for granted.
Thank you for this marvelously detailed video, I had time only for 5 or 6 minutes before skipping to the end. On mentioning " using Wheatstone bridge circuit for use with strain guages" to a Gloucester Engineering Manager years ago, It was mentioned he was associated with Gloucester and worked for Marconi .
Vitally necessary (for those of us into such topics), wonderfully researched and entertainingly delivered at a perfect pace. The highlighting of the documents to evidence what was said and when is a great touch. Superb :)
The basic bridge arrangement can also be used with two inductors or two capacitors as the top or bottom two elements, and that makes a very sensitive way to compare capacitors or inductors. The circuit can also be used with a gain element like a tube or transistor to make a very accurate oscillator or filter. Hewlett-Packard's first product was an audio oscillator that used such a bridge.
This is the first time I've heard a Wheatstone story that didn't include the fear of public speaking anecdote - which means I got to learn something. Well done.
Funny thing, I mentioned that he was scared of speaking in my last video and I was going to mention it again, but cut it out as it didn't need to be said twice. Glad I did.
I really liked listening to your lecture and as informative as you were, I was deeply happy with you as an endearingly sweet and quirky woman who reminded me of some of the most beloved in my family who, like you, always have something new for me to learn. Thank you, I look forward to watching more of your videos but now, as your subscriber.
Thanks for taking the time to share. Such a simple circuit but very important for the first precision or matched resistors . It all seems so simple and obvious now but in 1839 sourcing an electric charge,copper wire or other metal conductive wire took some scrounging as well as quantifying the electric charge s intensity and flow. The "Wheatstone" and Galv-meter led to the first calibration of tools to measure Volts Amperes and Ohms.
Thanks for putting the fun into math and science. I watch all of your videos over and over. I have an interest in math and science but limited ability so that is why even though I have taken lots of college classes I do not work in the field and I have lots of bad memories in college with great suffering in tests and exams. But I watch your videos over and over and the joyous fun comes back to studying math and science because we see the human side to it.
Great! The history behind this ubiquitous concept that we use today in school lab to highly sophisticated electronic control system is very very fascinating. Thank you.
The last time I used a Wheatstone Bridge was as a college student 20 years ago something with strain gages and pressure transducers. With my soldering technique, it was a good thing I was going into mechanical engineering.
I worked as a Technician for a resistor company back in the 70's & 80's. We used our own factory built high speed testers and these testers were built with the wheatstone principles, but were far more complex. We had a decade resistor network that was set to the nominal value, two tolerance dials which set the plus and minus tolerance of the resistor under test. And finally a compensation pot that nullified internal resistance. Instead of two coaxial cables going to the test resistor, there were four and a compensation network was also applied to these cables. Then it really got complicated in that we had to test on the 60 cycle crossover. This was to keep any outside interference from the test. That crossover detection went to the logic circuit where it fed an "and" gate along with the bridge sample and the result "good" 1 or "bad" 0 went to a shift register. That's about it except that I did not mention that the sample signal is developed by a bi-latteral switch which is running at 60Hertz.
In school i built a cryogenic fluid temperature measuring device based on the Wheatstone Bridge circuit. Nice to hear the history and especially the evolution of thought. We all learn from each other....to be better.
The long coil variable resistors were in common use into the 1950's. I have salvaged several old Fire Alarm systems that used them to account for different numbers of fire horns installed.
I think I must have found from somewhere (maybe a battery charging circuit?) a crude variable resistor, being a copper wire wound around a piece of asbestos board about 3in by 7in. The wiper was conected to a slider the top edge of the bread slice board and the feed to the first wire in the low position on the board. Interesting
Whatever you call it, the Wheatstone bridge had a huge influence in accurately measuring the surface stress in mechanical parts using strain gauges (resistance varies with the tension applied to a metallic wire). Today, and for a very long time, strain gauges are sold in a Wheatstone bridge array which will automatically compensate for fluctuations due the resistance change brought on by the thermal expansion or contraction of the metal to which the strain gauge array is affixed.
Jacobi’s “voltagometer” (“an improved rheostat markedly better than that by Poggendorf”) worked by suspending platinum wires in separate mercury containers. The mercury containers are connected by a platinum wire that can be raised or lowered to increase or decrease the length of platinum generated by the current, and hence the resistance. Got this from a Dutch book from 1860: “Over het meten van den galvanischen geleidingsweerstand inzonderheid bij metalen” By Hendrik W. Schroeder van der Kolk Incidentally, I like to find references in Dutch scientific literature, because traditionally, any educated Dutch person would have spoken German, English and French (and know Latin), so they were usually aware of more international publications than most).
Thanks for another great talk. Wheatstone also invented the ABC telegraph, which had the advantage of not needing expert telegraph operators at each end. Continued to be used till the 1930's in remote island locations without telegraph operators. Wheatstone seems to have been a bit of a dodgy character.
Alexander Bain invented the ABC Telegraph (it’s in the video) - Wheatstone plagiarised it. He also discovered the earth battery that transatlantic telegraphy uses.
@@da8ish1 Think just in United Kingdom. Was used in the Highlands and Islands as no need for expert telegraphers which was the drawback of the Morse system as it was used in practice.
OMG In America you have Edison who on account did innovations based on other inventors works, in the UK we have Wheatstone....What a story! Great video!!!!!!
Interesting you mentioned a means of testing low resistance values. . . Quite some years ago, I designed and built a 10 Amp "Earth Resistance" Tester. . .. Recently I had a failed Inverter, it tripped all its Battery feed breakers.. . I tested its DC input resistance with my "Earth Resistance" tester that uses an internal 12V battery and accurate 1 Ohm resistor, and found the DC input to that Inverter was down to 0.028 Ohm.. . . Years earlier there was a break on a UK-USA Cable, the special time fault locator was out of action, so the UK pulled out an old Wheastone Bridge and measured the fault o just of the USA coast.
Not so many people know that Wheatstone has a patent on the concertina, which is a 'squeezebox' musical instrument , a button accordion. These instruments depend on metallurgy to work, but it is not clear how much prior work was done
We used the principles for the wheat stone bridge to calibrate or certify many measurement tools but the most unique application was used in gas chromatography where using one leg measured heat loss from a gas sample stream while the other leg was maintained as a standard. It's more than a paragraph, real time process instruments are complicated
Hello Kathy, I'm not a total geek but I have to laugh hearing "Wheatstone Bridge" start my HVAC education in the 70's and soon after became a tech for Honeywell and offering classes on Honeywell products to contractors in the industry. The Wheatstone Bridge or reostat was a topic that was reviewed often . Thank you!
“Prof. Wheatstone has shown me an instrument, found on exactly the same principle as mine... Now it is quite impossible that he should have had the least notice of my instrument.” Unless there is mistakes in the translation from German to English, the text suggested that Wheatstone has came up with the rheostat using Ohm law, and also that it is impossible for Wheatstone to see Jacobi' instrument prior. A simple explanation why you could not find Jacobi's rheostat drawing could be he has never published it, since he thought the rheostat was insignificant comparing to the motor. If I am not mistaken Wheatstone could not have seen it. May be some other ideas was lifted by Wheatstone, but for the rheostat, knowing Ohm law he could come up with it by himself.
"A simple explanation why you could not find Jacobi's rheostat drawing could be he has never published it" Such a drawing exists and he did publish it - check out the pinned comment.
This is my 2nd video of this Kathy person. She's certainly got a good angle on tech, and she tells a good story! During the first video, the thought occurred, as my orbital muscles fatigued from tracking all the left and right motion across the bottom of the screen: would young Kathy be able to talk if someone tied her hands? 0:02 I got
17:30 Fascinating parallels to the etymological origin of name adopted by an American based cult religious following (something to do with pyramid of Giza being a 'witness of god'), which also appeared in print in this context, interpreted literally then passed into the public domain after catching on.
Great video. This is exactly the period of electrical history that I am interested in. (I'm working on a suspended coil galvanometer right now) Liked and Subbed.
17:58 - correction: Lord Kelvin was Irish. However, he spent his formative years after his father was made a professor of mathematics in Glasgow, and when he was ennobled, it was with a Scottish lordship. This is why he sometimes mistakenly gets called "Scottish".
You should also cover Oliver Heavyside. He was involved at this time and people don't talk about him enough. You could also talk about how the Heavyside transform became known as the Laplace transform.
I was glad to see that you did make it clear that Wheatstone’s bridge is balanced. I so dislike the misuse of the term by so many students who must get it from their teachers. Measuring zero current is so much easier than an actual current as the linearity of the measurement does not matter. Knowing the lost in translation and loss of references is interesting. Germanic use of references is different, or so I have been told, by those who fail to reference my work.
I used to think that the overwhelming feature of a Wheatstone bridge was to nullify any confusion generated by the impedance of the meter. When balanced, there is no current in the meter.
Yes, a wonderful side effect he was not aware of as it shows up in AC. A similar advantage in DC being the resistance of the meter but that one never causes much trouble.
This is kind of funny… during my apprenticeship in industrial electronics back in the early 1980s, I had never heard of the Wheatstone bridge (or balance) even though we used it for several theoretical calculations and practical measurements… I even used it later in the late 80s for electronic leveler adjustments. That is, until 2012-ish when I interviewed with a company and drew a Graetz bridge (actually invented by Karol Pollak) and the guy performing the interview called it a Weyermann bridge… I told him I had never heard of that definition before, but that I would take his word for it (I actually didn’t and looked it up and came across the Wheatstone bridge… never told him that he had both the name and the type of bridge wrong though) but for a good 30 years I never knew the name Wheatstone bridge… Thank you for the interesting story of Christie, Wheatstone, Cooke, Jacobi, Siemens, et.al.
Pollak patented his invention in 1895 in Britain and in 1896 in Germany so i find it interesting that Pollak invention is named after German scientist that published papper about it in 1897... In German or Russian article on wikipedia about that bridge there is not even a single word about Pollak. In English article there is information that Greatz invention was fully independent, i would like to learn how they confirmed that he did not know about something that was allready patented in his country year before he wrote about it...
Many inventions and discoveries are named after the wrong person, or the second person to discover it. This is especially true in mathematics, where there are dozens of theorems named not after the guy who actually discovered it, but the after the guy who brought attention to it.
I don't think I ever got a Wheatstone Bridge that could not be solved. We were given them with some of the legs with more than one resister, not given the ohms given on the resisters but other Voltage or amps, for us to work out the Ohms from the voltages and current around it. It sometimes took half the black board to work it out.
Jacobi's rheostat was called "volt-agometer" or "agometer". Sources: Tenth annual report of the Board of Regents of the Smithsonian Institution (English), Pierer's Lexicon (German, 1857-1865) and Nordisk Familjebok (Swedish, 1800s edition). According to the report, it was a costly instrument and quickly supplanted by Wheatstone's rheostat. A description of the agometer is supposed to be found in Poggendorff's Annalen, LIV 340, and LIX 145. I've not been able to access this.
Jacobi later teamed up with the German chemist Julius Lothar Meyer, who became incensed over Wheatstone's antics, and persuaded Jacobi to sue Wheatstone. To this end, the two formed the law firm of Jacobi & Meyer... (If you live in Southern California and listen to talk radio, you'll get this.)
I have an idea for a magnetic motor. Please point out the flaws. First, there are no Souths to deal with. All the magnets are Halbeck configs. Take 15 stationery magnets and put them in a circle. (24 x 15 = 360) Then take 2 more and place them on an armature opposite each other, like 2 cars on a Ferris wheel. Place them close to the stationery ones. Since 15 is an odd number and 2 an even one, they will never interfere with each other. No Souths to worry about. Once the 2 rotating magnets are set in motion, you should be able to adjust the flux and get spin from the pushing 15 fixed ones. To accelerate, simply rotate the fixed ones like a distributor shaft. Well?
The bridge was a excellent idea.its been awhile since ive used one though.i love your topics.ie ohms law the rosetta stone of electronics as far as im concerned.great job.
I always find fascinating those years of great discoveries made with rudimentary tools. It is impossible for me to imagine that Ohm's law was not known and that voltage and current were still not clear concepts.
The 5 wire telegraph always struck me as odd because you really only need 4 wires. With two batteries and one wire as the return path, you get 27 combinations.
Talk about a body electric: A wheatstone bridge is a major component of a lie detector. It is also the basis of the "E-meter" used by scientologists to guide their Dianetic "auditing" sessions. I once got my hands on an E-meter and soon learned that I could control it with my thoughts. As an actor might do, if I thought happy contented peaceful confident thoughts, the meter needle would move up to 4, And if I thought to put angry disturbed violent fearful thoughts into my brain, the needle would go down towards 1. At any rate, this is just to say that the connection between electrical resistance and human thoughts is fascinating.
I love that i found your channel. It is perfect. This was a really fascinating episode, I had no idea about Wheatstone - after using his name for forty years. I was playing with my AVO bridge today. Engineering esp. seems full of injustices. What doesn't help is the route to invention is blurred with so many hands adding a contribution. The Tesla phenomenon annoys me the most. I'm particularly taken with Blumlein and Armstrong who between them seemed to have discovered everything in my field, and of course Faraday and Maxwell in the pure sciences. Maxwell makes Tesla seem like a pimple in my opinion.
Can you make a video on explain electromagnetic waves ,I can't able to imagine that how electromagnetic waves travel and how they discoverd by hertz experiment . because hertz experiment is similar to Faraday electromagnetic induction experiment with high-voltage.
You might like my video on how Faraday came up with the idea of EM waves and how that led to Maxwell's equations and then Hertz's experiment. However, I think I should correct you as Hertz's experiment was very different to Faraday's electromagnetic induction experiment. Faraday discovered that changing a magnetic field in a coil of wire would induce current in that coil of wire. Hertz, discovered that an alternating electric field would travel at the speed of light and could be "caught" a distance away as a way of validating that light is an electromagnetic wave. Hope that helps.
Hello .I just found you . I was a cable splicer for CNT Canada in the70 s I used a WHEAT STONE for cable work but no idea now how we did it . GOD BLESS I watched more ,4 ohms to the loop mile ,get the Resistance to the cable or wire drive to location good luck . Buddies watching help me here
Of course he deserves his recognition - indeed in his paper (of c1843) he even disclosed the priority of the earlier scientist. This is not a matter of a patent priority, it is a development of the science.
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12:43 -- Jacobi did publish a picture of his rheostat in 1842:
Jacobi, M.H. (1842) "Beschreibung eines verbesserten Voltagometers" (Description of an improved voltagometer)
Bulletin Scientifique publié par l’Académie impériale des sciences de Saint-Pétersbourg, 10: columns 285-288. Three diagrams appear after column 288.
Wow! Thank you thank you thank you! I don’t speak German or French and I was having a heckuva time finding it. ❤️❤️❤️
@@Kathy_Loves_Physics -- You're welcome. 🙂 If you want a translation of the article, I could provide one. (It would take a few days to type it up. And I'd need an e-mail address to which I could send it.)
Good find. However; he saw Wheatstone's rheostat in 1840, but not published his book until 1842, so why Kathy implied Wheatstone had seen Jacobi’s before 1840 (20:39) by repeating the quote “quite impossible” in the text? The whole sentence means otherwise.
@@htooloo365 -- Yes. At 8:28 the text of Jacobi's article states that Jacobi thought that Wheatstone could Not have known about Jacobi's rheostat when Wheatstone invented his own version of a rheostat. So in Jacobi's opinion, they had invented the rheostat independently. The text originally appeared on p. 21 of: Jacobi (1840) "On the principles of electro-mechanical machines" Tenth Meeting of the British Association for the Advancement of Science: Notices and Abstracts of Miscellaneous Communications to the Sections pp. 18-24.
@@Kathy_Loves_Physics did you ever get back to Kevin Byrne who said he could translate for you.
When I was a kid, remember my physics teacher muttering darkly that "It isn't Wheastone's bridge, it's a Christie's bridge"...the text-books said otherwise. Thanks for clearing that up!!
Another home run! I would like to add as an aircraft technician, this concept is used to measure the density of the fuel by weight, using capacitors instead of resistors. The variable capacitance being the fuel compared to a known reference capacitance.
where can I read more about this in your application? I am a marine technician specializing in electronics, networks, and sensors... also working on my own engine instrumentation systems. thanks
And so far it has worked perfectly! I have never ran out of fuel whilst flying, yet………….
Kathy! You are just a great story teller! For me that's by far the best way to teach science to the public by telling its history! Thank you!
Hans ,quite agreeing with you!
I third that!
Great story teller, but please don't flap your arms about so much, I got nauseous watching them.
Would be amazing to see film footage of these early "electronic" inventors at work in their laboratories, if only that was possible. Would be great to see close ups of them making all the inventions at the various stages.
The context you use to describe these basics of electricity and magnetism is most enlightening. As-in the true historical machinations and personalities behind these leap-frog discoveries.
Thank you Kathy.
Thanks, never heard of Moritz von Jacobi before, but I did hear of use his Maximum power theorem. Basically always match impedances for maximum power transfer, it is one of those things that is as fundamental as ohms law and taken for granted. In the RF world most circuits are designed to have 50 ohms on their inputs (e.g. reference clocks) and outputs (e.g antennas). In designing high speed address and data buses in computers the impedance of all the transmission lines on the PCB's (Printed Circuit Boards) would all be designed to match the input and output of everything on the buses (e.g. memory, I/O and CPU) which is typically 50 to 60 ohms.
I love your video as always! Thank you.
I was tempted to mention his maximum power equation but the video was already so long that I had to cut it. Jacobi deserves his own video honestly. Glad you liked this video and thanks for always commenting
More famous than Moritz probably is his brother Carl Gustav Jacob Jacobi (en.wikipedia.org/wiki/Carl_Gustav_Jacob_Jacobi) at least in mathematical circles.
As a former EE student, these names, these people are the Hallowed saints of electronics (Voltaire, Ohm, Wheatstone, etc). Thank you so much for bringing them to life, and for showing them to be human; warts, misrepresentations and all.
Voltaire was a philosopher among other things.
I believe you mean Volta. Alessandro Volta, the Italian physicist.
Volta, not Voltaire, sorry
Voltaire? .Really!? What about Ampère?
Voltaire does not belong here, his contribution is about other stuff
@@geertfdevries9518 Though it must be said that Voltaire could electrify his readers.
I'm so happy to have discovered this RUclips channel! Wonderful content charmingly presented.
This is the first mention of the Wheatstone Bridge I've heard since I left Ma Bell many years ago.
Years ago telephone central offices had a test desk. In most cases it looked like one of the old corded switchboards operators worked from. The test desk took trouble reports from customers, tested them, dispatched a technician if necessary and then closed the ticket after noting what had been done to clear the problem. Most of them have disappeared if not because most testing is now done in the field by the technicians and the whole process has become computerized.
Every test desk had a Wheatstone Bridge mounted in a drawer. The test deskman (old terminology) used it to measure resistances on cable troubles using a Murray Test Or a Varley Test. A technician would call in and the testdesk using the cable plats send him to the farthest end of the cable and short circuit the pair of wires in trouble. The pair of wires would be connected to the bridge. If one side of the pair was grounded he would measure the resistance through the short circuit to ground. Then he'd reverse the bridge and look thought short in the other direction. Using a math formula and consulting the cable plats showed the overall resistance and capacitance the cable he could put the technician within a few feet of the problem location. I the cable was running in the air the outside temperature was factored in. Buried cable was consistent in temperature. Mixed buried and aerial cable caused a fluctuation in the math but a good test desk man could still get you very close.
At the time which was before the 1970s all the test deskmen were cable repairmen and a few equipment technicians tired of working outside in the weather. Some of the equipment technicians would transfer into the central office as Switchmen. That all changed in 1970 when the company women in these technical position to satisfy the Equal Employment Opportunity Commission. Without the field experience most of the women did the testing poorly. for the women it was all about money. The technical positions were filled with men and they paid better than the mostly clerical positions women were in. Almost immediately the company developed computerized testing. Once it had saturated the system almost all the testdesk personnel were downgraded to a clerical position that paid less and required less skill. The line cards were removed and the records were computerized. In an entire region there were one or two testdesk technicians and his testdesk used trunks to test in any troubles for the entire region. The Wheatstone Bridges. Eventually the Wheatstone Bridges disappeared. So did almost all of the technicians. The system is so computerized that people with those skills are no longer needed. That and the reduction of telephone lines on copper. Computers now compress thousands of telephones on what once could only carry one. Now you can get your telephone on a coax cable carrying your television signal and Internet service. Or you can just use a cellphone with a satellite dish for television. The installers now using technician as a title are installers. They have so little knowledge of equipment and electronics they are not technicians in reality
The Wheatstone Bridge left with the technicians and they aren't coming back.
That was the #12 test desk.
@@gpwgpw555 Yeah, that was the old one. I would sometimes go inside to cover someone on vacation. We had a "temporary" test center using 2A cabinets.
You must be another old timer. We're disappearing fast. It seems like someone passes every other month. And not very old either. The business really changed. The smaller COs have no one working in them. The cable techs make the inside connections, at least they used to until the SMAZ frames. Good Luck.
@@robertcuminale1212 42 years as a switchman in Oklahoma City. I loved 37 years of it. In the last five years we became customer driven. meaning we did not fix anything unless customers reported trouble.
Hey, Jacobi didn't write that it was impossible that they had come up with the same idea independently, he wrote that it was impossible that Wheatstone "should have had the least notice of my instrument", implying that he was convinced that they HAD come up with the same idea independently.
Thanks for these videos!
And in the next sentence he praises Wheatstone for the wide variety of uses as a measuring tool that Wheatstone found for this device while himself only used it as a regulator. This is an extra argument for independent simultaneous discovery since they both created their device for different purposes.
@@christianbarnay2499 people at that time would choose politeness over direct confrontation to cope with public known figures stealing their ideas and decide to be the bigger person by attributing praise on the stealer not for stealing but in order to showing no hard feelings but they had internally recognised their own acheivements and felt it
@@kevindoom You can still politely criticize the attitude of someone, just like Cooke did when he clearly disapproved Wheatstone claiming their collaborative work as his own. When Jacobi says that Wheatstone and himself created the same instrument independently for different purposes (Jacobi needed a regulating device, Wheatstone needed a measuring device) there are no valid reasons to not believe him.
@@christianbarnay2499 i am the person that is on jacobis side in the first place
@@christianbarnay2499 whetstone was declaring that he independantly came up with it but in the exact same way the exact same way it was obvious of course Jacobi knew but he decided to deal with it politely
Wonderful! Thank you. Knowing the history of inventions is so helpful in really understanding the components!
Love your enthusiasm, Kathy.
Thanks
I worked in a research and testing facility for a few years. When checking some background information on strain gauge measurements (you should know some basics of what you do), I also got to know Wheatstone's bridge.
The measuring amplifiers nowadays are quite easy, you click on a button in the software to set all strain gauges to zero before the measurement, but in "ancient" times so had to tune one of the resistors in the Wheatstone bridges for each individual strain gauge by hand to start the measurement at 0 (or whatever value you liked).
very nice and helpful to bring their names back to life
New follower here... I've worked in electronics most of my life and understand it as well as the next guy... I guess, but I've only known little snatches here and there of the history behind it all. I love your videos. Gets me closer to something I've always taken for granted.
Another most enjoyable "inside story", Kathy. Good presentation and graphics. Thank you!
Thank you for this marvelously detailed video, I had time only for 5 or 6 minutes before skipping to the end. On mentioning " using Wheatstone bridge circuit for use with strain guages" to a Gloucester Engineering Manager years ago, It was mentioned he was associated with Gloucester and worked for Marconi .
You are a natural Teacher. Thanks.
Vitally necessary (for those of us into such topics), wonderfully researched and entertainingly delivered at a perfect pace. The highlighting of the documents to evidence what was said and when is a great touch. Superb :)
Thanks
The basic bridge arrangement can also be used with two inductors or two capacitors as the top or bottom two elements, and that makes a very sensitive way to compare capacitors or inductors. The circuit can also be used with a gain element like a tube or transistor to make a very accurate oscillator or filter. Hewlett-Packard's first product was an audio oscillator that used such a bridge.
This is the first time I've heard a Wheatstone story that didn't include the fear of public speaking anecdote - which means I got to learn something. Well done.
Funny thing, I mentioned that he was scared of speaking in my last video and I was going to mention it again, but cut it out as it didn't need to be said twice. Glad I did.
always disliked those things, professor did a poor job(don't really need them 2 fix stuff) since the whole class was lost.
Your videos on physics history are amazing Kathy, thanks.
I really liked listening to your lecture and as informative as you were, I was deeply happy with you as an endearingly sweet and quirky woman who reminded me of some of the most beloved in my family who, like you, always have something new for me to learn. Thank you, I look forward to watching more of your videos but now, as your subscriber.
Thanks for taking the time to share. Such a simple circuit but very important for the first precision or matched resistors . It all seems so simple and obvious now but in 1839 sourcing an electric charge,copper wire or other metal conductive wire took some scrounging as well as quantifying the electric charge s intensity and flow. The "Wheatstone" and Galv-meter led to the first calibration of tools to measure Volts Amperes and Ohms.
Thanks for putting the fun into math and science. I watch all of your videos over and over. I have an interest in math and science but limited ability so that is why even though I have taken lots of college classes I do not work in the field and I have lots of bad memories in college with great suffering in tests and exams. But I watch your videos over and over and the joyous fun comes back to studying math and science because we see the human side to it.
Thank you for teaching us all.. GREAT!
You are a 'charismatic' educator / illuminator ... Thank you for sharing the 'back story' that is never shared in school.
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Thank you
I love your channel! its a breath of fresh air because most of these subjects are not discussed historically
Great! The history behind this ubiquitous concept that we use today in school lab to highly sophisticated electronic control system is very very fascinating.
Thank you.
So glad you liked it. Certainly fell down the rabbit hole with that one
Ms Kathy, your videos are very informative and well made. Thank you so much.
The last time I used a Wheatstone Bridge was as a college student 20 years ago something with strain gages and pressure transducers. With my soldering technique, it was a good thing I was going into mechanical engineering.
8:25 Surely, Jacobi writes, "it is quite impossible that he should have had the least notice of my instrument"
I worked as a Technician for a resistor company back in the 70's & 80's. We used our own factory built high speed testers and these testers were built with the wheatstone principles, but were far more complex. We had a decade resistor network that was set to the nominal value, two tolerance dials which set the plus and minus tolerance of the resistor under test. And finally a compensation pot that nullified internal resistance. Instead of two coaxial cables going to the test resistor, there were four and a compensation network was also applied to these cables. Then it really got complicated in that we had to test on the 60 cycle crossover. This was to keep any outside interference from the test. That crossover detection went to the logic circuit where it fed an "and" gate along with the bridge sample and the result "good" 1 or "bad" 0 went to a shift register. That's about it except that I did not mention that the sample signal is developed by a bi-latteral switch which is running at 60Hertz.
Absolutely brilliant again, thanks!
So much research. It’s nice to get context on all these things which we now take for granted
Amazing stuff, I have used Wheatstone bridges in some of my designs, and it is amazing to know a bit of history on it. Please make more videos :P.
Glad you liked it. Am working hard on new videos but it is always slower than I would wish. (I have about 80 videos on RUclips for while you wait)
Very well done, thank you for teaching physics in such an easy manner to comprehend.
In school i built a cryogenic fluid temperature measuring device based on the Wheatstone Bridge circuit.
Nice to hear the history and especially the evolution of thought. We all learn from each other....to be better.
Good job! You are a good teacher!
The long coil variable resistors were in common use into the 1950's. I have salvaged several old Fire Alarm systems that used them to account for different numbers of fire horns installed.
I think I must have found from somewhere (maybe a battery charging circuit?) a crude variable resistor, being a copper wire wound around a piece of asbestos board about 3in by 7in. The wiper was conected to a slider the top edge of the bread slice board and the feed to the first wire in the low position on the board. Interesting
Whatever you call it, the Wheatstone bridge had a huge influence in accurately measuring the surface stress in mechanical parts using strain gauges (resistance varies with the tension applied to a metallic wire). Today, and for a very long time, strain gauges are sold in a Wheatstone bridge array which will automatically compensate for fluctuations due the resistance change brought on by the thermal expansion or contraction of the metal to which the strain gauge array is affixed.
It also applies to electrical meters, Ex: Western Electric 22A transmission test set.
Kudos for your excellent videos!
Jacobi’s “voltagometer” (“an improved rheostat markedly better than that by Poggendorf”) worked by suspending platinum wires in separate mercury containers. The mercury containers are connected by a platinum wire that can be raised or lowered to increase or decrease the length of platinum generated by the current, and hence the resistance.
Got this from a Dutch book from 1860:
“Over het meten van den galvanischen geleidingsweerstand inzonderheid bij metalen”
By Hendrik W. Schroeder van der Kolk
Incidentally, I like to find references in Dutch scientific literature, because traditionally, any educated Dutch person would have spoken German, English and French (and know Latin), so they were usually aware of more international publications than most).
Thanks for another great talk. Wheatstone also invented the ABC telegraph, which had the advantage of not needing expert telegraph operators at each end. Continued to be used till the 1930's in remote island locations without telegraph operators. Wheatstone seems to have been a bit of a dodgy character.
Interesting. Yeah, he was dodgy, I should have used that term, perfect to describe him IMHO
do you know if they were ever used in the old west?
Alexander Bain invented the ABC Telegraph (it’s in the video) - Wheatstone plagiarised it. He also discovered the earth battery that transatlantic telegraphy uses.
@@da8ish1 Think just in United Kingdom. Was used in the Highlands and Islands as no need for expert telegraphers which was the drawback of the Morse system as it was used in practice.
OMG In America you have Edison who on account did innovations based on other inventors works, in the UK we have Wheatstone....What a story! Great video!!!!!!
This channel is so great
Interesting you mentioned a means of testing low resistance values. . . Quite some years ago, I designed and built a 10 Amp "Earth Resistance" Tester. . .. Recently I had a failed Inverter, it tripped all its Battery feed breakers.. . I tested its DC input resistance with my "Earth Resistance" tester that uses an internal 12V battery and accurate 1 Ohm resistor, and found the DC input to that Inverter was down to 0.028 Ohm.. . . Years earlier there was a break on a UK-USA Cable, the special time fault locator was out of action, so the UK pulled out an old Wheastone Bridge and measured the fault o just of the USA coast.
Well done. Thank you.
Thanks for making the video.
You are welcome
I really enjoy your videos! They are superb.
Glad you like them!
Very interesting development. Thanks for the history of electricity.
Not so many people know that Wheatstone has a patent on the concertina, which is a 'squeezebox' musical instrument , a button accordion. These instruments depend on metallurgy to work, but it is not clear how much prior work was done
We used the principles for the wheat stone bridge to calibrate or certify many measurement tools but the most unique application was used in gas chromatography where using one leg measured heat loss from a gas sample stream while the other leg was maintained as a standard.
It's more than a paragraph, real time process instruments are complicated
Look up Siemens industrial gas chromatography, there are others but that name is mentioned
This is why many researchers today do flag placing and upload their first draft to Arxiv. So that they can show they are first.
Hello Kathy, I'm not a total geek but I have to laugh hearing "Wheatstone Bridge" start my HVAC education in the 70's and soon after became a tech for Honeywell and offering classes on Honeywell products to contractors in the industry. The Wheatstone Bridge or reostat was a topic that was reviewed often . Thank you!
“Prof. Wheatstone has shown me an instrument, found on exactly the same principle as mine... Now it is quite impossible that he should have had the least notice of my instrument.”
Unless there is mistakes in the translation from German to English, the text suggested that Wheatstone has came up with the rheostat using Ohm law, and also that it is impossible for Wheatstone to see Jacobi' instrument prior.
A simple explanation why you could not find Jacobi's rheostat drawing could be he has never published it, since he thought the rheostat was insignificant comparing to the motor. If I am not mistaken Wheatstone could not have seen it. May be some other ideas was lifted by Wheatstone, but for the rheostat, knowing Ohm law he could come up with it by himself.
"A simple explanation why you could not find Jacobi's rheostat drawing could be he has never published it"
Such a drawing exists and he did publish it - check out the pinned comment.
I had not heard this history before. Great video
Thank you, what a find. Those who contributed to the sciences, thir story has to be told. Nicely done. Cheers!
This is my 2nd video of this Kathy person. She's certainly got a good angle on tech, and she tells a good story! During the first video, the thought occurred, as my orbital muscles fatigued from tracking all the left and right motion across the bottom of the screen: would young Kathy be able to talk if someone tied her hands?
0:02 I got
Kath dishes the dirt on the convoluted electrical history. Love it.
Just wanted to say thanks for your Chanel for the information on science in regard of the history of the time, very informative 👍
You are welcome Paul. Glad you liked it.
17:30 Fascinating parallels to the etymological origin of name adopted by an American based cult religious following (something to do with pyramid of Giza being a 'witness of god'), which also appeared in print in this context, interpreted literally then passed into the public domain after catching on.
Great video. This is exactly the period of electrical history that I am interested in. (I'm working on a suspended coil galvanometer right now) Liked and Subbed.
Just come across this channel. No idea if anyone has mentioned this but the Peter Roget is the same Roget of thesaurus fame!
Beautiful.
17:58 - correction: Lord Kelvin was Irish. However, he spent his formative years after his father was made a professor of mathematics in Glasgow, and when he was ennobled, it was with a Scottish lordship. This is why he sometimes mistakenly gets called "Scottish".
I knew someone else would catch this one! I love these videos. Keep it up, Kathy!
You should also cover Oliver Heavyside. He was involved at this time and people don't talk about him enough. You could also talk about how the Heavyside transform became known as the Laplace transform.
He’s on the list but it is a very long list
I was glad to see that you did make it clear that Wheatstone’s bridge is balanced. I so dislike the misuse of the term by so many students who must get it from their teachers. Measuring zero current is so much easier than an actual current as the linearity of the measurement does not matter. Knowing the lost in translation and loss of references is interesting. Germanic use of references is different, or so I have been told, by those who fail to reference my work.
I used to think that the overwhelming feature of a Wheatstone bridge was to nullify any confusion generated by the impedance of the meter. When balanced, there is no current in the meter.
Yes, a wonderful side effect he was not aware of as it shows up in AC. A similar advantage in DC being the resistance of the meter but that one never causes much trouble.
It also removes the battery impedance.
This is kind of funny… during my apprenticeship in industrial electronics back in the early 1980s, I had never heard of the Wheatstone bridge (or balance) even though we used it for several theoretical calculations and practical measurements… I even used it later in the late 80s for electronic leveler adjustments. That is, until 2012-ish when I interviewed with a company and drew a Graetz bridge (actually invented by Karol Pollak) and the guy performing the interview called it a Weyermann bridge… I told him I had never heard of that definition before, but that I would take his word for it (I actually didn’t and looked it up and came across the Wheatstone bridge… never told him that he had both the name and the type of bridge wrong though) but for a good 30 years I never knew the name Wheatstone bridge…
Thank you for the interesting story of Christie, Wheatstone, Cooke, Jacobi, Siemens, et.al.
Pollak patented his invention in 1895 in Britain and in 1896 in Germany so i find it interesting that Pollak invention is named after German scientist that published papper about it in 1897...
In German or Russian article on wikipedia about that bridge there is not even a single word about Pollak.
In English article there is information that Greatz invention was fully independent, i would like to learn how they confirmed that he did not know about something that was allready patented in his country year before he wrote about it...
Many inventions and discoveries are named after the wrong person, or the second person to discover it.
This is especially true in mathematics, where there are dozens of theorems named not after the guy who actually discovered it, but the after the guy who brought attention to it.
Yippie! And Thanks again for all the videos.
Glad you like them! Cheers, K
Love your content
I wish I had your knowledge and motivation, fantastic!
Thanks
Again you crush my belief in weatstones achievements lol
I don't think I ever got a Wheatstone Bridge that could not be solved. We were given them with some of the legs with more than one resister, not given the ohms given on the resisters but other Voltage or amps, for us to work out the Ohms from the voltages and current around it. It sometimes took half the black board to work it out.
Jacobi's rheostat was called "volt-agometer" or "agometer". Sources: Tenth annual report of the Board of Regents of the Smithsonian Institution (English), Pierer's Lexicon (German, 1857-1865) and Nordisk Familjebok (Swedish, 1800s edition).
According to the report, it was a costly instrument and quickly supplanted by Wheatstone's rheostat.
A description of the agometer is supposed to be found in Poggendorff's Annalen, LIV 340, and LIX 145. I've not been able to access this.
Why aren't your videos recommended more!!!
I donno. I sure wish they were.
Jacobi later teamed up with the German chemist Julius Lothar Meyer, who became incensed over Wheatstone's antics, and persuaded Jacobi to sue Wheatstone. To this end, the two formed the law firm of Jacobi & Meyer...
(If you live in Southern California and listen to talk radio, you'll get this.)
I have an idea for a magnetic motor. Please point out the flaws. First, there are no Souths to deal with. All the magnets are Halbeck configs. Take 15 stationery magnets and put them in a circle. (24 x 15 = 360) Then take 2 more and place them on an armature opposite each other, like 2 cars on a Ferris wheel. Place them close to the stationery ones. Since 15 is an odd number and 2 an even one, they will never interfere with each other. No Souths to worry about. Once the 2 rotating magnets are set in motion, you should be able to adjust the flux and get spin from the pushing 15 fixed ones. To accelerate, simply rotate the fixed ones like a distributor shaft. Well?
The bridge was a excellent idea.its been awhile since ive used one though.i love your topics.ie ohms law the rosetta stone of electronics as far as im concerned.great job.
After a half a century of using the bridge I now know how it got it's strange name, KOOL
I always find fascinating those years of great discoveries made with rudimentary tools. It is impossible for me to imagine that Ohm's law was not known and that voltage and current were still not clear concepts.
Coming up with Ohms law before knowing the difference between current and voltage is amazing.
Your videos are fun and amazing...and under-watched. Found you by accident. Subscribed.
thank you 👍
excellent
The 5 wire telegraph always struck me as odd because you really only need 4 wires.
With two batteries and one wire as the return path, you get 27 combinations.
Talk about a body electric: A wheatstone bridge is a major component of a lie detector. It is also the basis of the "E-meter" used by scientologists to guide their Dianetic "auditing" sessions. I once got my hands on an E-meter and soon learned that I could control it with my thoughts. As an actor might do, if I thought happy contented peaceful confident thoughts, the meter needle would move up to 4, And if I thought to put angry disturbed violent fearful thoughts into my brain, the needle would go down towards 1. At any rate, this is just to say that the connection between electrical resistance and human thoughts is fascinating.
This is good stuff !
Thanks
Intro song never gets old
I will tell Kim (the singer) :)
Peter Roget 4:23 of Roget’s Thesaurus fame? I think Edison was closely taking notes from Wheatstone’s behavior.
Breezed over Roget who is best known for helping you find just the right word.
I love this woman.
Aww thanks
I love that i found your channel. It is perfect. This was a really fascinating episode, I had no idea about Wheatstone - after using his name for forty years. I was playing with my AVO bridge today.
Engineering esp. seems full of injustices. What doesn't help is the route to invention is blurred with so many hands adding a contribution. The Tesla phenomenon annoys me the most.
I'm particularly taken with Blumlein and Armstrong who between them seemed to have discovered everything in my field, and of course Faraday and Maxwell in the pure sciences. Maxwell makes Tesla seem like a pimple in my opinion.
Can you make a video on explain electromagnetic waves ,I can't able to imagine that how electromagnetic waves travel and how they discoverd by hertz experiment . because hertz experiment is similar to Faraday electromagnetic induction experiment with high-voltage.
You might like my video on how Faraday came up with the idea of EM waves and how that led to Maxwell's equations and then Hertz's experiment. However, I think I should correct you as Hertz's experiment was very different to Faraday's electromagnetic induction experiment. Faraday discovered that changing a magnetic field in a coil of wire would induce current in that coil of wire. Hertz, discovered that an alternating electric field would travel at the speed of light and could be "caught" a distance away as a way of validating that light is an electromagnetic wave. Hope that helps.
Gracias!
Hello .I just found you . I was a cable splicer for CNT Canada in the70 s I used a WHEAT STONE for cable work but no idea now how we did it . GOD BLESS I watched more ,4 ohms to the loop mile ,get the Resistance to the cable or wire drive to location good luck . Buddies watching help me here
There were Wheatstone test sets built into the number 12 test desk.
It is proper to give credit in his paper and if he did so how much more can be asked?
Honestly, I find it hilarious that one of the most notorious uses of a Wheatstone Bridge, is as the e-Meter in Scientology.
Of course he deserves his recognition - indeed in his paper (of c1843) he even disclosed the priority of the earlier scientist. This is not a matter of a patent priority, it is a development of the science.