Thank you very much. Your explanations are top-tier and straight to the point. Been working my head around potentiostat circuits, who knew all I needed was 19 minutes in pine research instruments.
Glad you enjoyed the video! Also, as a heads up we are doing a free webinar on how potentiostats work and iR compensation this Thursday March 7. pineresearch.com/webinar-registration/ if you want to know more check it out.
Thank you! Op amps can definitely be more complicated and I only mentioned enough about them to help with understanding a potentiostat. Glad the video was helpful!
Wow, that's a huge complement. Thank you! Veritasium is awesome, and great at making science really accessible. I'm just going to focus on the Echem related topics though :)
Amazing explanation, easy to understand as visuals were helping a lot. Things are confusing while reading hard or electronic book as we need to divide our attention many times. Really appreciate your effort for making concepts as simple as possible.
Thank you! Great question. A two-electrode configuration would be the case where the counter and reference electrodes are connected on one side, and the working sense + working drive electrodes are connected on the other side. But it would be the same operation by the potentiostat. The issue with two-electrode configurations is that as current flows from the counter electrode, the reference electrode potential starts to change. But the feedback mechanism is the same. I hope this was helpful.
Another great video! Would be really interesting to discuss the pros and cons of different measuring topologies, for example grounding directly the WE and putting a series resistor betweem the output of the control opamp and CE, or putting WE at virtual ground using a transimpedance amplifier.
Thanks a great suggestion Luiz. Honestly, I would need to talk to my electrical engineer to know how that works and what the pros and cons of such a configuration would be. I think my goal was just to get grad students using a potentiostat for the first time, a chance to understand how it works from a fundamental perspective. But this is definitely something worth looking into for future videos.
@@Pineresearch And for sure you achieved your goal! I believe that would be an interesting discussion for precision measurements. I'll keep an eye out for it!
Thank you very much, I am glad you enjoyed the video! We can certainly add a bipot operation to our ideas for possible content in the future, though to be honest the explanation of bipotentiostat operation is considerably more complicated than even the potentiostat is, and the schematic we use to describe a potentiostat here is already very simplified for educational purposes. To be blunt, I am not sure how easy or understandable it would be to simplify a bipotentiostat schematic and operation. But we appreciate the suggestion and we will keep it in mind for sure!
This is really nice for beginners like me. One question that bothers me why do we need a reference electrode at all. As you told we are applying a potential wrt ground initially, what is the purpose of having the reference electrode in the circuit. I know this question may sound weird but I am not clear at this point 😕
Hello Soumya, great question. The idea behind the reference electrode is that you want to have a stable reference point in your electrochemical system. If you could have "ground" in your electrochemical cell I bet people would do it. But if you apply a voltage between the working and counter, both electrodes experience some kind of electrochemical process to maintain charge balance. That inherently means that potential at both electrodes changes. If you want to know the potential difference between the working and counter, that's easy, but it doesn't tell you anything because the counter electrode potential might be drifting a lot during the experiment. All that being said, 2-electrode experiments are common, and depending on the application you could get away without using a potentiostat, and just using a power supply to do experiments. I hope that was helpful!
Thank you Brhane! You'll have to talk to our competitor Bio-Logic for a Cyclic Voltammetry video with EC-Lab software. But I do have plans for making a Cyclic Voltammetry video in the near future! 😀
This video really looked great from the perspective of getting a deeper understanding about the potentiate but could you please recommend a video on "three electrode system" working which can cover the very basics. Actually, I am very beginner to Electrochemistry and I would be really thankful for your help. TIA
Not a problem. I'd recommend checking out our introduction to cyclic voltammetry video. ruclips.net/video/cz67DnyS9-w/видео.html It doesn't cover all the details of a three electrode system, but I think it's a good starting point. We also have free webinars every couple of months (pending how busy we are) that go over some of the basics of electrochemistry.
Yes, I watched this video and I feel once again grateful for introducing me to the CV. It really helped it but actually I was looking for the whole phenomenon of three electrode system like why we need to use 3 electrode system instead of 2 electrodes system? Why it is necessary to keep the reference electrode? I mean the very basic questions like this. TIA
@@hamidqazi7021 I had this question too when I was learning Echem, it's not intuitive. If you had a two-electode system you could measure the potential difference between the two electrodes, and drive current between them to induce reactions, and let's say the current is kept constant and the potential is allowed to vary such that oxidation reactions and reduction reactions occur on the two electrodes. Because these reactions are occurring, it means the potential between them is changing (current is constant). So if I want to know more about the thermodynamics of the oxidation reaction I can measure the potential between the two electrodes and I get a potential associated with the oxidation reaction. But the problem is that potential is a relative quantity, the measured potential of the oxidation reaction is with respect to a changing electrode (the other electrode undergoing a reduction reaction). As such we employ a reference electrode in a 3 electrode configuration to maintain a stable reference potential that we can measure the working electrode (electrode of the oxidation reaction) potential against. If we measure the working electrode potential against an electrode where the potential is changing (electrode with reduction reactions), when we won't have an accurate measurement. As a side note, we are thinking about doing a Q&A livestream in the future. Would you mind if we used this question to kick off the livestream?
@@Pineresearch Thank you so much for a detailed response to my query. Indeed, it cleared some of my doubts. Referring to your Q&A session so yes off-course, I would like to request you to please inform me before arranging it, so that I may not miss it.
@@hamidqazi7021 Awesome! Yeah, stay tuned to our channel, we'll make an announcement and probably have a scheduled LiveStream you'll see on our channel.
Hello guys, why the feedback goes into the non-inverting input of the op-amp? A voltage follower is by the definition an inverting-type device, so the feedback should go into the inverting input. Isn't it? Nice video, by the way!
Thank you! So just to clarify, are we talking about the voltage follower circuit, or the simplified potentiostat circuit? Voltage follower circuit from the video has the feedback going into the inverting input which creates negative feedback (although I didn't talk about negative and positive feedback in the video). For the potentiostat circuit, there was the electrochemical cell and electrometer inbetween the output voltage of the high gain op-amp, and the Vfeed back. At the end of the day, Vfeedback has to be equal to the potentiostatic set point otherwise the potentiostat wouldn't work properly. I hope this answers your question.
@@Pineresearch big thanks for your prompt follow-up! Yes, I meant the simplified potentiostat circuit. I can see somewhat differing simplified circuits for a potentiostat on different sites or in reference materials, so it seems to be okay to have variations in this simplified circuit. Also, the explanation in the video makes good sense to me. However, if the high gain opamp is functioning as a voltage follower, as it is defined in the literature, then any feedback should be connected to its inverting input by definition, otherwise we could not call that circuit a voltage follower, in my understanding. Finally, let me thank you for this video again. I teach a microbial electrochemistry-related subject to students, and your video was very useful in my class.
@@gabormehes1665 I'm glad you've found this video helpful and that you are sharing it with your students! There are a bunch of different simplified potentiostat circuits out in the literature, all should be valid to some extent, but sometimes difficult to conceptually understand. So in the strictest sense the voltage follower circuit doesn't have any other circuit elements in the feedback loop. The moment you add things like resistors and capacitors into the feedback loop, it is no longer a voltage follower. We have the electrochemical cell and electrometer in the feedback loop, which changes the Vfeed. We could flip the inverting and noninverting inputs on the electrometer and get positive feedback rather than negative feedback into the high gain op-amp. I would say that the voltage follower is conceptually needed to understand potentiostat operation. Please let me know if you have any questions. Where are you teaching microbial electrochemistry?
Great discussion. Could you tell that electrochemical station is in potentiostat or galvanostat mode during a cyclic voltammetry experiment? Both current and potential is changing in this technic!
Great question. During a cyclic voltammetry experiment, we are controlling the potential and measuring the resulting current, so this would be a potentiostat.
An Excellent Informative Video. But I would like to ask you a question what is the basic difference between a DC Power Supply and a Potentiostat and how electrochemical corrosion studies i.e. electrochemical polarization, EIS studies etc. can be performed using a DC supply for electrochemical experiment
Hello Surajit Sinha. Great question. The main difference between a DC power supply and a potentiostat is the implementation of a reference electrode and a feedback loop to maintain a desired potential. A reference electrode is important because it represents a stable reference point when measuring the potential of one of your electrodes. As current flows across your electrochemical cell, both the counter and working electrode potentials will change, so you won't know which electrode is responsible for a chance in the potential. With regards to electrochemical polarization and EIS, it might be possible to use a DC power supply along with a linear sweep generator, but DC power supplies typically don't have the ability to different specific potential waveforms. I would also say that doing EIS is basically impossible to do with a DC power supply. EIS is an AC voltammetry technique, so a DC power supply won't work. I hope this was helpful.
@@Pineresearch Thank you very much for this valuable information. I want some guidance from your side. I have a Programmable 60 V DC Power Supply and I want to perform electrochemical corrosion studies of a certain material. So how do I perform in a two-electrode cell configuration and also how to measure corrosion voltage and corrosion current by developing a Tafel extrapolation plot from this DC Source. In your previous comment, you mentioned the linear sweep generator to be connected to the DC supply. So I want to know about digital storage oscilloscopes and can I use them to generate potential waveforms and perform EIS studies??
@@surajitsinha9055 Hello Surajit, I'm not sure exactly how to use the DC power supply for corrosion studies, and it will probably depend on what materials you are studying. I have limited experience with corrosion studies but in general, you need to keep the potential of your material very close to the open circuit potential, and only make slight adjustments to the potential (+ or - 10 mV), if you apply something as large as +1 V away from the open circuit potential you will most likely corrode the material like crazy and get limited corrosion data. The DC power supply will supply power to your system but I don't know how it will measure the potential and the current, you might need a digital multimeter. I do not know of any digital oscilloscopes that can be used to generate the waveforms to perform EIS, but I would recommend purchasing a potentiostat for doing all these studies. Doing EIS manually will be extremely time consuming and you need fitting data to analyze your EIS data. I would check out our website for a WaveDriver 100 potentiostat with EIS, that can do all your corrosion and EIS experiments. pineresearch.com/shop/potentiostats/wavedriver-series/wavedriver100-bundles/
Thank you for video, I am using the Potentiostatt with multiple channels but I don't know how to connect all the instruments to potentiostat so could you please make a video on the actual measurement from beginning_
Glad you enjoyed the video. I would need to know more about your electrochemical system (electrodes, electrolyte, etc) as well as your instruments to know how everything is connected. But for a multichannel potentiostat you can think of simply duplicating the single channel potentiostat process multiple times. I hope that helps
Nice explanation, Do you know how other resistances affect the user given potential. So to be more exact we try to investigate electrochemical properties of gold-nanoparticles (Au-NPs), but we want to investigate optical properties of these nanoparticles as well. So we used an thin layer of ITO to apply a potential on the Au-NPs (the NPs are just dropped on the layer) . The problem is, that this ITO layer has a resistance of ~4000 Ohm. So the potential difference measured between REF and WRKsense is the potential at the Au-NPs plus the Voltage dropping at the ITO layer, right? (It's like putting an ohmic resistor at the alligator clip of the working electrode and connecting this to the cell.) First, are my thoughts on that correct? And second, do you know to really control the potential at the Au-NPs and not the sum of NPs and ITO. I know it's a really specific question, but it would be super nice to get some help there. Thank you anyways for the video
Hello Jonas. I think your understanding of the system is correct. It is like putting a big resistor between your WRKsense and REF lead in the potentiostat. There is a voltage drop that needs to be compensated for to get the user potential = the potential between the WRKsense and REF. This ultimately allows your chemistry to occur, but the potential values will be inaccurate. I have two thoughts with regard to potential control of the Au-NPs independent of ITO. First, you could try a series of experiments with the Au-NPs deposited on a glassy carbon electrode, or another conductive material, and see if you get a change in voltage. The other thing you could do is Electrochemical Impedance Spectroscopy (EIS), where you could attempt to model your system with a circuit equivalent, to know what the resistance of the Au-NPs, and perhaps other useful information about them. I guess I have 3rd idea. There is a technique called bipolar electrochemistry. You effectively have the Au-NPs on a non-conductive surface, but in-between the working and counter electrode. The electric field from the electrodes induces an electric field in the Au-NPs. It's kind of like a wireless electrochemistry technique. I don't know that much about it. Richard Crooks at UT Austin is an expert in the field and has a few articles on it. But that would be a way to control the potential of the Au-NPs without the ITO. I hope this was helpful.
You might need to speak with an electrical engineer to get the details, but the potential waveform itself (for CV/DPV techniques) is created at the potentiostatic set point. So the simplified potentiostat design makes sure that the potential you set is equal to the difference between the working and reference electrode, via the feedback mechanism, but you'll probably want a waveform generator connected to your potentiostatic set point to create the CV and DPV techniques. At this point you might want to purchase a potentiostat.
Very very nice video. I have a query related to REFERENCE ELECTRODE. This is designed to keep it at a constant potential. Instead of using this specially designed reference electrode, can I use a voltage supply to connect one end of the voltage supply with the ε- of the electrometer and other end of the voltage supply being grounded?
That's a good question. It sounds like you are trying to set the potential of the reference lead through an external power supply that is disconnect with the electrochemical solution. This in principle would keep the potential stable and not run into the issues that "traditional" reference electrodes have. So there are a few issues with this setup. Remember that the electrometer output will be the voltage difference between the reference and working sense electrode. However, applying a set potential through an external power source into the reference lead will be the potential vs ground, but it won't necessarily be the potential vs the working. Potential and voltage are relative quantities, and the voltage measured from the power supply will be different that the potential measured inside the electrochemical cell. There needs to be a single reference point in the solution that everything is connected to. Breaking the electrical connections between the 3 electrodes will break the feedback circuit. I hope this was helpful. Its best to use a traditional reference electrode, rather than an external power supply.
@@Pineresearch hahahaha, i would've make more intelegent comment if i know you would read my comment. Really good video man! very very clear explanation for something i've never heard about
I have a question. Since you are saying that output of high gain op-amp will continue to adjust until both of its input voltages become equal. This is actually virtual ground concept in electronics. It states that voltage at inverting and non-inverting terminals should be same. But this works only when there is negative feedback i.e. when feedback loop is connected to inverting terminal of the op-amp. But here, you are giving feedback from positive terminal i.e. non-inverting terminal. Then how both the inputs are becoming equal here?
This is a very good and technical question, and to be completely transparent I am not 100% certain I can give the best answer from an electronics perspective. But I can try to give you two answers that may clarify things for you: First, I think it may not matter that the feedback goes into the non-inverting input because it is coming from the Electrometer, which is outputting the voltage measured between REF and WRK Sense, which could be essentially any value. So the feedback loop involves an iterative process and the change in the input does not necessarily only go in one direction just because it is fed to the non-inverting input, meaning it can (and does) converge to reach your setpoint. Second, there is actually one other aspect of the circuitry for a potentiostat that we intentionally omit in this video for the sake of simplicity and clarity of explanation. In reality, there is actually bypass circuitry that goes around the high-gain op-amp called the stability filter, and it is essentially capacitive elements used to help reduce oscillations and speed up the convergence of the feedback loop. What it also means is that technically the mathematics and assumed process of iteration described in this video is not perfectly accurate (again, this was intentional!), but rather that process is impacted by this unseen filter and additional algorithmic programming. I apologize if this last point makes it even murkier to conceptualize, but again that is largely the reason we chose to exclude this element from the video to try and simplify the explanation.
You'll have to forgive me because I'm a chemist, and not an electrical engineer. I only consulted our electrical engineer when coming up with this video. But I omitted a few things from the actual potentiostat circuit for simplicity. There is a capacitor in feedback (connected between the output of the op-amp and the inverting input) with the inverting input on the operational amplifier. We call it the stability filter as it helps modulate the potentiostat response rate. In a way there is a negative feedback loop to the inverting input on the op-amp. I understand that negative feedback is necessary for the potentiostat to work. What I don't understand (as a chemist) is why does it need to be through the inverting input on the op-amp. Unless the equation I'm using to describe the op-amp is incorrect. -gain(inverting input - non-inverting input) = output voltage. But there are other potentiostat circuit diagrams that have it the other way around. I'm honestly not sure.
When the potential changes at Working sense electrode as a result of potential change at working drive, does the potential get amplified when it goes into the non-invariant input of electrometer.
Perhaps there is a slight misunderstanding or interpretation to the output voltage from the counter electrode. I would say that there is a voltage difference between the counter and the working drive electrode, and this voltage is what drives current through the electrochemical cell. The only place for current to go is the working drive electrode because it has the lowest resistance. The reference and working sense leads are connected to the Op-amp inputs with high impedance. But the potential does not get amplified when it is measured at the electrometer.
Thank you very much for your video. I want to ask a question. In the potentiostatic, if we set a constant voltage (1 V), how dose the potential of working electrode and counter electrode change? For instance, the initial voltage of working electrode is 0.5V (vs ref.).
Great question! So if the difference between the working and ref is +0.5 V and you want to change it to +1 V. You set the potential at the potentiostatic setpoint to +1.0 V. At the high gain op-amp the equation is -Beta*(e_ - e+)= Vo. Vo is the output voltage at the counter electrode. In your case, you would have -Beta*(1-0.5) = -Beta*0.5. Because Beta is a very large number it amplifies the output of the counter electrode, but it's sign is negative (-Beta). So the output voltage of the counter electrode is a large negative number. The counter electrode will continue to apply this large negative potential until the difference between the working and reference electrode is = +1 V. At that point e_ and e+ at the high gain op-amp will be the same and the output at the counter electrode would be zero. I hope this was helpful and clarifies things. Please let me know if you have any further questions.
Is anyone knows where this equipment available in India (especially in South) ... If know please give me details🙏🏻.... I have to do thesis research regarding corrosion by using this potentiostat.... Please help me🙏🏻
Hello Anil. You can purchase Pine Research Potentiostat's from our India Distributor Bat-Sol. www.bat-sol.com/ There sales email address is sales@bat-sol.com You should ask them for a WaveDriver 40 to do corrosion experiments.
Hie.... Electrode (Electrochemical cell ) has three terminal............ WRKsense and WRKdrive are same , WRK connected to both electrometer E+ and Rwrk ...... is it correct ???
WRKsense and WRKdrive are connected to each other in a typical electrochemistry experiment, but they are connected to different things in the potentiostat circuit. The WRKsense is connected to the electrometer for measuring the potential, and WRKdrive is connected to the sense resistor Rwrk. Does that make sense?
Whenever your computer communicates with your potentiostat to change the working electrode potential, it does so through the counter electrode voltage. So counter electrode voltage is controlled indirectly through how you set the working electrode potential, via the potentiostatic set point. I hope this helps.
Actually there are a few decently Arduino build your own potentiostat papers out there. I don't know if they use the same circuit as this one, but they do exist.
There are a lot of different areas of electrochemistry you could go into. First, is this a PhD, MS, or Bachelors program? 2nd are you more into chemistry, engineering, or physics? Based on these the range of different degrees and focuses you can go into are quite large, but we can make some recommendations once we know what you like.
@@Pineresearch it is my 3rd year in bachelors of general chemistry. We will be asked to select our major in 4th year for research that was why I was asking. My physics is not good though.
@@farhanaahmad408 Of course! We talk to a lot of undergrad and graduate students about careers in academia and industry. First and foremost you should do research that you are interested in. That will be regardless of it's applications and career opportunities, if you aren't interested in the research or work then you'll just be miserable. Electrochemistry does require some physics but honestly I believe that anybody can learn it, it takes time and practice. I would recommend you do whatever research you think is exciting and interesting.
Your video is just inspiring. Can I ask for your permission to repost your videos to a Chinese video platform called Bilibili? Most Chinese people can't access RUclips because of the censorship policies in mainland China. I believe that your videos deserve wide dissemination. I will add CN subtitles, and make sure to ALWAYS include your channel's name, video link, and credit you as the original author in the video description. Have a good day!
I think you reached out to us earlier about another RUclips video you want to post on Bilibili. I need to know more details about how the translation will work. Please email pinewire@pineresearch.com for us to continue the conversation.
Whoever decided to make you the teacher deserves a promotion or a raise, love your explanations mate. They're straightforward and relatively simple
Thank you for the kind words. I really appreciate it! Glad you enjoyed the video.
Exceptional educator by the day, System fo a Down Revival vocalist by the night, as I would like to believe. Thank you!
Thank you! It takes a lot of work trying to make these videos. Some people, Some people, Some people call it insane, yeah they call it insane.
Thank you very much. Your explanations are top-tier and straight to the point. Been working my head around potentiostat circuits, who knew all I needed was 19 minutes in pine research instruments.
Glad you enjoyed the video! Also, as a heads up we are doing a free webinar on how potentiostats work and iR compensation this Thursday March 7. pineresearch.com/webinar-registration/ if you want to know more check it out.
Thanks! Best explanation I had seen for Op Amps, which I wasn't expecting to find in my search for information on Potentiostats!
Thank you! Op amps can definitely be more complicated and I only mentioned enough about them to help with understanding a potentiostat. Glad the video was helpful!
Seems like I just watched a Veritasium video. Great quality, thanks!
Wow, that's a huge complement. Thank you! Veritasium is awesome, and great at making science really accessible. I'm just going to focus on the Echem related topics though :)
I am in love with your channel, and I like the way you simplify complex definitions .. Thanks man
Glad you like them! I'm hoping to get more videos turned out soon. Stay tuned!
Excellent video. Please continue to make more videos giving electrochemical education.
Will do!
Thank you so much, this would help me to understand more about the electrochemistry ❤️🙏
Glad it was helpful!
Amazing explanation, easy to understand as visuals were helping a lot. Things are confusing while reading hard or electronic book as we need to divide our attention many times. Really appreciate your effort for making concepts as simple as possible.
Absolutely! I'm glad this was helpful. And yes, as a chemist or chemical engineer its hard to understand electronics books.
Great video very clear explanation. I am also curious how two-electrode configuration potentiostat works.
Thank you! Great question. A two-electrode configuration would be the case where the counter and reference electrodes are connected on one side, and the working sense + working drive electrodes are connected on the other side. But it would be the same operation by the potentiostat. The issue with two-electrode configurations is that as current flows from the counter electrode, the reference electrode potential starts to change. But the feedback mechanism is the same. I hope this was helpful.
@@Pineresearch Thank you, yes, your explanation helps.
Another great video! Would be really interesting to discuss the pros and cons of different measuring topologies, for example grounding directly the WE and putting a series resistor betweem the output of the control opamp and CE, or putting WE at virtual ground using a transimpedance amplifier.
Thanks a great suggestion Luiz. Honestly, I would need to talk to my electrical engineer to know how that works and what the pros and cons of such a configuration would be. I think my goal was just to get grad students using a potentiostat for the first time, a chance to understand how it works from a fundamental perspective. But this is definitely something worth looking into for future videos.
@@Pineresearch And for sure you achieved your goal! I believe that would be an interesting discussion for precision measurements. I'll keep an eye out for it!
Lovely and informative! I would also be interested to know how a bipotentiostat works. Do you have plans to make a video on the topic?
Thank you very much, I am glad you enjoyed the video! We can certainly add a bipot operation to our ideas for possible content in the future, though to be honest the explanation of bipotentiostat operation is considerably more complicated than even the potentiostat is, and the schematic we use to describe a potentiostat here is already very simplified for educational purposes. To be blunt, I am not sure how easy or understandable it would be to simplify a bipotentiostat schematic and operation. But we appreciate the suggestion and we will keep it in mind for sure!
You are a good educator. Thank you for the video.
That is very kind, thank you! Appreciate you watching our video!
Thank you so much,excellent explanation.
Glad it was helpful!
Thanks again for the amazing video. I've always wanted to know how the potentiostat works. Just keep the videos coming!
Glad you enjoyed the video and learned something. We've got more videos in the pipeline :)
This guy is my unofficial professor for electrochemistry stuff
Hahaha thank you!
wow a really good intro to potentiostat!
Glad you enjoyed it!! :)
This is really nice for beginners like me. One question that bothers me why do we need a reference electrode at all. As you told we are applying a potential wrt ground initially, what is the purpose of having the reference electrode in the circuit. I know this question may sound weird but I am not clear at this point 😕
Hello Soumya, great question. The idea behind the reference electrode is that you want to have a stable reference point in your electrochemical system. If you could have "ground" in your electrochemical cell I bet people would do it. But if you apply a voltage between the working and counter, both electrodes experience some kind of electrochemical process to maintain charge balance. That inherently means that potential at both electrodes changes. If you want to know the potential difference between the working and counter, that's easy, but it doesn't tell you anything because the counter electrode potential might be drifting a lot during the experiment. All that being said, 2-electrode experiments are common, and depending on the application you could get away without using a potentiostat, and just using a power supply to do experiments. I hope that was helpful!
An amazing explanation!
Glad you liked it!!!
Perfect, Thank you
You're welcome!
Excellent explanation. Can you do a video on how to work with Cyclic voltammetry in EC-Lab software?
Thank you Brhane! You'll have to talk to our competitor Bio-Logic for a Cyclic Voltammetry video with EC-Lab software. But I do have plans for making a Cyclic Voltammetry video in the near future! 😀
thanks bro. expectional way of teaching.
Thank you!!!
Lovely explanation! Great job!
Thank you! I'm glad you liked it :)
This video really looked great from the perspective of getting a deeper understanding about the potentiate but could you please recommend a video on "three electrode system" working which can cover the very basics. Actually, I am very beginner to Electrochemistry and I would be really thankful for your help. TIA
Not a problem. I'd recommend checking out our introduction to cyclic voltammetry video.
ruclips.net/video/cz67DnyS9-w/видео.html
It doesn't cover all the details of a three electrode system, but I think it's a good starting point. We also have free webinars every couple of months (pending how busy we are) that go over some of the basics of electrochemistry.
Yes, I watched this video and I feel once again grateful for introducing me to the CV. It really helped it but actually I was looking for the whole phenomenon of three electrode system like why we need to use 3 electrode system instead of 2 electrodes system? Why it is necessary to keep the reference electrode? I mean the very basic questions like this. TIA
@@hamidqazi7021 I had this question too when I was learning Echem, it's not intuitive. If you had a two-electode system you could measure the potential difference between the two electrodes, and drive current between them to induce reactions, and let's say the current is kept constant and the potential is allowed to vary such that oxidation reactions and reduction reactions occur on the two electrodes. Because these reactions are occurring, it means the potential between them is changing (current is constant). So if I want to know more about the thermodynamics of the oxidation reaction I can measure the potential between the two electrodes and I get a potential associated with the oxidation reaction. But the problem is that potential is a relative quantity, the measured potential of the oxidation reaction is with respect to a changing electrode (the other electrode undergoing a reduction reaction). As such we employ a reference electrode in a 3 electrode configuration to maintain a stable reference potential that we can measure the working electrode (electrode of the oxidation reaction) potential against. If we measure the working electrode potential against an electrode where the potential is changing (electrode with reduction reactions), when we won't have an accurate measurement.
As a side note, we are thinking about doing a Q&A livestream in the future. Would you mind if we used this question to kick off the livestream?
@@Pineresearch Thank you so much for a detailed response to my query. Indeed, it cleared some of my doubts.
Referring to your Q&A session so yes off-course, I would like to request you to please inform me before arranging it, so that I may not miss it.
@@hamidqazi7021 Awesome! Yeah, stay tuned to our channel, we'll make an announcement and probably have a scheduled LiveStream you'll see on our channel.
Thanks for the explanation
Of course!!
I owe you. Thank you for sharing your knowledge.
Not a problem. Glad you enjoyed the video!
Hello guys, why the feedback goes into the non-inverting input of the op-amp? A voltage follower is by the definition an inverting-type device, so the feedback should go into the inverting input. Isn't it? Nice video, by the way!
Thank you! So just to clarify, are we talking about the voltage follower circuit, or the simplified potentiostat circuit? Voltage follower circuit from the video has the feedback going into the inverting input which creates negative feedback (although I didn't talk about negative and positive feedback in the video). For the potentiostat circuit, there was the electrochemical cell and electrometer inbetween the output voltage of the high gain op-amp, and the Vfeed back. At the end of the day, Vfeedback has to be equal to the potentiostatic set point otherwise the potentiostat wouldn't work properly. I hope this answers your question.
@@Pineresearch big thanks for your prompt follow-up! Yes, I meant the simplified potentiostat circuit. I can see somewhat differing simplified circuits for a potentiostat on different sites or in reference materials, so it seems to be okay to have variations in this simplified circuit. Also, the explanation in the video makes good sense to me. However, if the high gain opamp is functioning as a voltage follower, as it is defined in the literature, then any feedback should be connected to its inverting input by definition, otherwise we could not call that circuit a voltage follower, in my understanding. Finally, let me thank you for this video again. I teach a microbial electrochemistry-related subject to students, and your video was very useful in my class.
@@gabormehes1665 I'm glad you've found this video helpful and that you are sharing it with your students! There are a bunch of different simplified potentiostat circuits out in the literature, all should be valid to some extent, but sometimes difficult to conceptually understand. So in the strictest sense the voltage follower circuit doesn't have any other circuit elements in the feedback loop. The moment you add things like resistors and capacitors into the feedback loop, it is no longer a voltage follower. We have the electrochemical cell and electrometer in the feedback loop, which changes the Vfeed. We could flip the inverting and noninverting inputs on the electrometer and get positive feedback rather than negative feedback into the high gain op-amp. I would say that the voltage follower is conceptually needed to understand potentiostat operation. Please let me know if you have any questions. Where are you teaching microbial electrochemistry?
Great discussion. Could you tell that electrochemical station is in potentiostat or galvanostat mode during a cyclic voltammetry experiment? Both current and potential is changing in this technic!
Great question. During a cyclic voltammetry experiment, we are controlling the potential and measuring the resulting current, so this would be a potentiostat.
An Excellent Informative Video. But I would like to ask you a question what is the basic difference between a DC Power Supply and a Potentiostat and how electrochemical corrosion studies i.e. electrochemical polarization, EIS studies etc. can be performed using a DC supply for electrochemical experiment
Hello Surajit Sinha. Great question. The main difference between a DC power supply and a potentiostat is the implementation of a reference electrode and a feedback loop to maintain a desired potential. A reference electrode is important because it represents a stable reference point when measuring the potential of one of your electrodes. As current flows across your electrochemical cell, both the counter and working electrode potentials will change, so you won't know which electrode is responsible for a chance in the potential. With regards to electrochemical polarization and EIS, it might be possible to use a DC power supply along with a linear sweep generator, but DC power supplies typically don't have the ability to different specific potential waveforms. I would also say that doing EIS is basically impossible to do with a DC power supply. EIS is an AC voltammetry technique, so a DC power supply won't work. I hope this was helpful.
@@Pineresearch Thank you very much for this valuable information. I want some guidance from your side. I have a Programmable 60 V DC Power Supply and I want to perform electrochemical corrosion studies of a certain material. So how do I perform in a two-electrode cell configuration and also how to measure corrosion voltage and corrosion current by developing a Tafel extrapolation plot from this DC Source. In your previous comment, you mentioned the linear sweep generator to be connected to the DC supply. So I want to know about digital storage oscilloscopes and can I use them to generate potential waveforms and perform EIS studies??
@@surajitsinha9055 Hello Surajit, I'm not sure exactly how to use the DC power supply for corrosion studies, and it will probably depend on what materials you are studying. I have limited experience with corrosion studies but in general, you need to keep the potential of your material very close to the open circuit potential, and only make slight adjustments to the potential (+ or - 10 mV), if you apply something as large as +1 V away from the open circuit potential you will most likely corrode the material like crazy and get limited corrosion data. The DC power supply will supply power to your system but I don't know how it will measure the potential and the current, you might need a digital multimeter. I do not know of any digital oscilloscopes that can be used to generate the waveforms to perform EIS, but I would recommend purchasing a potentiostat for doing all these studies. Doing EIS manually will be extremely time consuming and you need fitting data to analyze your EIS data. I would check out our website for a WaveDriver 100 potentiostat with EIS, that can do all your corrosion and EIS experiments. pineresearch.com/shop/potentiostats/wavedriver-series/wavedriver100-bundles/
Thank you for video, I am using the Potentiostatt with multiple channels but I don't know how to connect all the instruments to potentiostat so could you please make a video on the actual measurement from beginning_
Glad you enjoyed the video. I would need to know more about your electrochemical system (electrodes, electrolyte, etc) as well as your instruments to know how everything is connected. But for a multichannel potentiostat you can think of simply duplicating the single channel potentiostat process multiple times. I hope that helps
Nice explanation,
Do you know how other resistances affect the user given potential.
So to be more exact we try to investigate electrochemical properties of gold-nanoparticles (Au-NPs), but we want to investigate optical properties of these nanoparticles as well.
So we used an thin layer of ITO to apply a potential on the Au-NPs (the NPs are just dropped on the layer) . The problem is, that this ITO layer has a resistance of ~4000 Ohm. So the potential difference measured between REF and WRKsense is the potential at the Au-NPs plus the Voltage dropping at the ITO layer, right? (It's like putting an ohmic resistor at the alligator clip of the working electrode and connecting this to the cell.)
First, are my thoughts on that correct?
And second, do you know to really control the potential at the Au-NPs and not the sum of NPs and ITO.
I know it's a really specific question, but it would be super nice to get some help there. Thank you anyways for the video
Hello Jonas. I think your understanding of the system is correct. It is like putting a big resistor between your WRKsense and REF lead in the potentiostat. There is a voltage drop that needs to be compensated for to get the user potential = the potential between the WRKsense and REF. This ultimately allows your chemistry to occur, but the potential values will be inaccurate.
I have two thoughts with regard to potential control of the Au-NPs independent of ITO. First, you could try a series of experiments with the Au-NPs deposited on a glassy carbon electrode, or another conductive material, and see if you get a change in voltage. The other thing you could do is Electrochemical Impedance Spectroscopy (EIS), where you could attempt to model your system with a circuit equivalent, to know what the resistance of the Au-NPs, and perhaps other useful information about them.
I guess I have 3rd idea. There is a technique called bipolar electrochemistry. You effectively have the Au-NPs on a non-conductive surface, but in-between the working and counter electrode. The electric field from the electrodes induces an electric field in the Au-NPs. It's kind of like a wireless electrochemistry technique. I don't know that much about it. Richard Crooks at UT Austin is an expert in the field and has a few articles on it. But that would be a way to control the potential of the Au-NPs without the ITO.
I hope this was helpful.
I'm also working on NPs, can you give me your email
@@zemiecheabdelmalik2858 You can reach out to us at pinewire@pineresearch.com You can then let us know more about what you're interested in.
How to make a potentiostat using discrete op-amps for CV/DPV techniques?
You might need to speak with an electrical engineer to get the details, but the potential waveform itself (for CV/DPV techniques) is created at the potentiostatic set point. So the simplified potentiostat design makes sure that the potential you set is equal to the difference between the working and reference electrode, via the feedback mechanism, but you'll probably want a waveform generator connected to your potentiostatic set point to create the CV and DPV techniques. At this point you might want to purchase a potentiostat.
that was awesome !
thank you sooo much !
You are very welcome! Glad you liked it!
That was perfect. Thank you
You are very welcome! Glad you liked it!
Very very nice video.
I have a query related to REFERENCE ELECTRODE. This is designed to keep it at a constant potential. Instead of using this specially designed reference electrode, can I use a voltage supply to connect one end of the voltage supply with the ε- of the electrometer and other end of the voltage supply being grounded?
That's a good question. It sounds like you are trying to set the potential of the reference lead through an external power supply that is disconnect with the electrochemical solution. This in principle would keep the potential stable and not run into the issues that "traditional" reference electrodes have. So there are a few issues with this setup. Remember that the electrometer output will be the voltage difference between the reference and working sense electrode. However, applying a set potential through an external power source into the reference lead will be the potential vs ground, but it won't necessarily be the potential vs the working. Potential and voltage are relative quantities, and the voltage measured from the power supply will be different that the potential measured inside the electrochemical cell. There needs to be a single reference point in the solution that everything is connected to. Breaking the electrical connections between the 3 electrodes will break the feedback circuit. I hope this was helpful. Its best to use a traditional reference electrode, rather than an external power supply.
@@Pineresearch Nice. Thank you so much.
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I assume you liked the video. Thanks!
@@Pineresearch hahahaha, i would've make more intelegent comment if i know you would read my comment. Really good video man! very very clear explanation for something i've never heard about
I have a question. Since you are saying that output of high gain op-amp will continue to adjust until both of its input voltages become equal. This is actually virtual ground concept in electronics. It states that voltage at inverting and non-inverting terminals should be same. But this works only when there is negative feedback i.e. when feedback loop is connected to inverting terminal of the op-amp. But here, you are giving feedback from positive terminal i.e. non-inverting terminal. Then how both the inputs are becoming equal here?
This is a very good and technical question, and to be completely transparent I am not 100% certain I can give the best answer from an electronics perspective. But I can try to give you two answers that may clarify things for you:
First, I think it may not matter that the feedback goes into the non-inverting input because it is coming from the Electrometer, which is outputting the voltage measured between REF and WRK Sense, which could be essentially any value. So the feedback loop involves an iterative process and the change in the input does not necessarily only go in one direction just because it is fed to the non-inverting input, meaning it can (and does) converge to reach your setpoint.
Second, there is actually one other aspect of the circuitry for a potentiostat that we intentionally omit in this video for the sake of simplicity and clarity of explanation. In reality, there is actually bypass circuitry that goes around the high-gain op-amp called the stability filter, and it is essentially capacitive elements used to help reduce oscillations and speed up the convergence of the feedback loop. What it also means is that technically the mathematics and assumed process of iteration described in this video is not perfectly accurate (again, this was intentional!), but rather that process is impacted by this unseen filter and additional algorithmic programming. I apologize if this last point makes it even murkier to conceptualize, but again that is largely the reason we chose to exclude this element from the video to try and simplify the explanation.
You'll have to forgive me because I'm a chemist, and not an electrical engineer. I only consulted our electrical engineer when coming up with this video. But I omitted a few things from the actual potentiostat circuit for simplicity. There is a capacitor in feedback (connected between the output of the op-amp and the inverting input) with the inverting input on the operational amplifier. We call it the stability filter as it helps modulate the potentiostat response rate. In a way there is a negative feedback loop to the inverting input on the op-amp.
I understand that negative feedback is necessary for the potentiostat to work. What I don't understand (as a chemist) is why does it need to be through the inverting input on the op-amp. Unless the equation I'm using to describe the op-amp is incorrect. -gain(inverting input - non-inverting input) = output voltage. But there are other potentiostat circuit diagrams that have it the other way around. I'm honestly not sure.
When the potential changes at Working sense electrode as a result of potential change at working drive, does the potential get amplified when it goes into the non-invariant input of electrometer.
Perhaps there is a slight misunderstanding or interpretation to the output voltage from the counter electrode. I would say that there is a voltage difference between the counter and the working drive electrode, and this voltage is what drives current through the electrochemical cell. The only place for current to go is the working drive electrode because it has the lowest resistance. The reference and working sense leads are connected to the Op-amp inputs with high impedance. But the potential does not get amplified when it is measured at the electrometer.
Thank you very much for your video. I want to ask a question. In the potentiostatic, if we set a constant voltage (1 V), how dose the potential of working electrode and counter electrode change? For instance, the initial voltage of working electrode is 0.5V (vs ref.).
Great question! So if the difference between the working and ref is +0.5 V and you want to change it to +1 V. You set the potential at the potentiostatic setpoint to +1.0 V. At the high gain op-amp the equation is -Beta*(e_ - e+)= Vo. Vo is the output voltage at the counter electrode. In your case, you would have -Beta*(1-0.5) = -Beta*0.5. Because Beta is a very large number it amplifies the output of the counter electrode, but it's sign is negative (-Beta). So the output voltage of the counter electrode is a large negative number. The counter electrode will continue to apply this large negative potential until the difference between the working and reference electrode is = +1 V. At that point e_ and e+ at the high gain op-amp will be the same and the output at the counter electrode would be zero. I hope this was helpful and clarifies things. Please let me know if you have any further questions.
Thanks!
You're Welcome! Thanks for watching.
Thanks a lot
You are very welcome!
Is anyone knows where this equipment available in India (especially in South) ... If know please give me details🙏🏻.... I have to do thesis research regarding corrosion by using this potentiostat.... Please help me🙏🏻
Hello Anil. You can purchase Pine Research Potentiostat's from our India Distributor Bat-Sol. www.bat-sol.com/
There sales email address is
sales@bat-sol.com
You should ask them for a WaveDriver 40 to do corrosion experiments.
Hie.... Electrode (Electrochemical cell ) has three terminal............
WRKsense and WRKdrive are same , WRK connected to both electrometer E+ and Rwrk ...... is it correct ???
WRKsense and WRKdrive are connected to each other in a typical electrochemistry experiment, but they are connected to different things in the potentiostat circuit. The WRKsense is connected to the electrometer for measuring the potential, and WRKdrive is connected to the sense resistor Rwrk. Does that make sense?
Could you tell me on what parameter CE voltage is changed?
Whenever your computer communicates with your potentiostat to change the working electrode potential, it does so through the counter electrode voltage. So counter electrode voltage is controlled indirectly through how you set the working electrode potential, via the potentiostatic set point. I hope this helps.
@@Pineresearch Thanks for reply.. Can you also tell me how to convert the current (converted to voltage using TIA) through WE to moles in solution?
@@PoeticBugBear We've got a video for that too ruclips.net/video/OuKvJVRPatk/видео.html. You can convert charge into moles using Faradays constant
Now, I wonder how to build a potentiostat as in DIY project... 😅
Actually there are a few decently Arduino build your own potentiostat papers out there. I don't know if they use the same circuit as this one, but they do exist.
I am thinking of pursuing degree in electro, anybody who can recommend channels?
There are a lot of different areas of electrochemistry you could go into. First, is this a PhD, MS, or Bachelors program? 2nd are you more into chemistry, engineering, or physics? Based on these the range of different degrees and focuses you can go into are quite large, but we can make some recommendations once we know what you like.
@@Pineresearch it is my 3rd year in bachelors of general chemistry. We will be asked to select our major in 4th year for research that was why I was asking. My physics is not good though.
@@Pineresearch thank you for replying. I just can't tell you how much it meant to me.
@@farhanaahmad408 Of course! We talk to a lot of undergrad and graduate students about careers in academia and industry. First and foremost you should do research that you are interested in. That will be regardless of it's applications and career opportunities, if you aren't interested in the research or work then you'll just be miserable. Electrochemistry does require some physics but honestly I believe that anybody can learn it, it takes time and practice. I would recommend you do whatever research you think is exciting and interesting.
Your video is just inspiring. Can I ask for your permission to repost your videos to a Chinese video platform called Bilibili? Most Chinese people can't access RUclips because of the censorship policies in mainland China. I believe that your videos deserve wide dissemination. I will add CN subtitles, and make sure to ALWAYS include your channel's name, video link, and credit you as the original author in the video description. Have a good day!
I think you reached out to us earlier about another RUclips video you want to post on Bilibili. I need to know more details about how the translation will work. Please email pinewire@pineresearch.com for us to continue the conversation.
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