Science topics: Current

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# Current - Science topic

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Questions related to Current

we're using dual-chamber MFC in this project and connect it with multimeter (UNI-T, UT61E+ multimeter) to record the current reading (per minute) for 2 weeks. we didn't connect resistor to the circuit, so it would be hard to calculate the current if we use the multimeter to record the voltage. Plus, the current that we've obtained now only reach microampere, so I'm not sure if resistor is necessary here. Hence, we use the multimeter to only record the current, and use it to calculate the current density later. Can I do that?

Please, how can I calculate the total current (or global i) from the capacitive cyclic voltammogram (CV curve as shown in the attached figure)?

Thank you in advance.

Hello All

I have measured the corrosion current and corrosion rate through the Tafel polarisation three-electrode system.

Working electrode - mild steel, the counter electrode - graphite., reference electrode - SCE, Electrolyte - seawater.

The corrosion rate and corrosion currents are increased with the linear increase of operational current (instrument current range) from 10 nA to 1 A.

Please can anyone share the reason for this? and how do I fix the current range (e.g., 1 mA, 100 mA) for corrosion measurement?

Thanks

Vinooth.

Hello everyone, I want to use DHI Mike software to draw the ocean residual current field, but I don't know what the specific operation steps are, please kindly help me out, thank you.

Good morning,

I would like to know if it is possible to add leakage current to the grid?

When I simulate a GaN HEMT, I have extremely low currents after the Vth (1e-14...). I would like to have more like 1e-5...

I use for that the command #SURF.REC E.TUNNEL BARRIER at the gate contact. Is it necessary to add particular models?

Nevertheless, I have big problems of convergences and also too much leakage current (1e-2...)

I specify that I use workfunctions at the drain/source and gate to simulate

Thank you for your answer and for your help.

In contrast to diodes (that maintain a relatively constant voltage when the current through them varies (https://www.researchgate.net/post/How_does_a_diode_maintain_a_constant_voltage), a fundamental property of all types of transistors (BJT, FET...) is to maintain a relatively constant current when the voltage across them varies. How do they do that?

As in the case of diodes, this question can be answered specifically by considering the processes in the semiconductor device. But again it would be interesting to explain this on a conceptual level by revealing the basic idea. As I have already said, this "philosophical" approach has several advantages: first, it does not require in-depth knowledge of semiconductor devices; second, it would be applicable to all 2-terminal devices that have this property. I will do this using the concept of "dynamic resistance".

Generally speaking, a transistor behaves like a resistor that interferes with current creating a voltage drop and heat loss. In the initial steep part of its output IV curve, this "resistor" has a relatively constant low resistance. And if it was really a resistor, the curve would continue in the same direction.

However, when the current threshold of the respective transistor is reached (set by the base-emitter voltage or current), the curve changes its slope and becomes almost horizontal. The voltage continues to change but the current stops changing. Why? Here is my simple explanation…

*When the voltage V increases, the transistor also increases its static resistance R with the same rate of change. So, the current through the transistor I = V/R does not change.*This is a simple arithmetic trick where we change the numerator and denominator of a fraction in the same direction and with the same rate of change; as a result, the quotient of the division does not change (see the attached picture).

Thus, by changing its resistance in the same direction with the current, this "dynamic resistor" maintains a constant current. This clever "transistor trick" can be graphically illustrated (https://en.wikibooks.org/wiki/Circuit_Idea/Group_67b#A_transistor_acting_as_a_current-stable_resistor) - see the second attached picture below.

Tomorrow I have an online exercise on Semiconductor Devices with my students of group 48b, ITI, FCST of Technical University of Sofia, that is about transistor applications. Maybe I will illustrate to them this viewpoint by means of ZOOM pen drawing moving IV curves. And again, to get the attention of my students, I would tell them another fun story - that I could mimic any transistor they wanted with just a variable resistor ("potentiometer")... and that if I hid in a big box, they would think that there is a transistor inside:-)

The next day... Done! Here is a part of the video record (https://photos.app.goo.gl/EqonSNBjzT6Cw2Dj7, in Bulgarian) and the attached screenshot.

It would be interesting for me to know your opinion on my explanation.

I am not been able to differentiate between two quantities in the context of BJT.

These two quantities are: Is and Icbo.

According to Sedra Smith, Icbo is the collector base reverse current. Whereas Is is the saturation or scale current.

I have been wondering are these two quantities same or share some relation between them because I find the name for both these quantities being used inter-changeably at many places which is quite confusing and I believe they are not the same.

Also, I am confused which current is being referred to when on Internet I find the term "reverse saturation current". Searching on Internet the term "reverse saturation current" gives two kinds of sources: one referring it as Is and the other referring it as Icbo. Another similar quantity is Iceo.

Please see attached images for equations.

Dear scientific colleagues,

I consulted an article on IEEE Chakrabarti, A. Krier and A. F. Morgan, "Analysis and simulation of a mid-infrared P/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30//n/sup 0/-InAs/sub 0.89/Sb/sub 0.11//N/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30/ double heterojunction photodetector grown by LPE," in IEEE Transactions on Electron Devices, vol. 50, no. 10, pp. 2049-2058, Oct. 2003, doi: 10.1109/TED.2003.815604.

I would like to know, how or under what basis the equations 26a, 26b, 26c and 267 were established, to calculate the current. Kindly help

When we look for a marker or an antibody to incubate or to use in electrophoresis or western, we need to look at some requirements before its use. Apart from the MW requirements, what else do you need to look at? (Is it the same in the case of an antibody for incubation?). What do you do with them? How to use the information contained in them? Is there anything you need to discard where to look?

do I include any leakage current model in order to obtain leakage current

And why does it matter? The intrinsic combination of ambi-polar device give can enhance on-to-off current ratio.

When you apply an electricidad current to the electrophoresis you need to bare in mind the voltage is spread evenly between the two sides. There must be enough for both. Is it more than just half or double? When you do not apply half?

Please suggest the some methods to collect data from Internet or other sources through which I can collect data for Regional Research Study.

Thank you in advance 😊

Is it possible to find current conductivity of a molecule using gaussian software? The molecule was experimentally proved to be conducting. If it is possible to find, how can we done that?

For example, if the duty cycle is 50%, does average current reduced to 50%?

We know that by drawing a magnet close to a closed circular circuit, a current in the circuit is induced. Why? (I don't mean the mathematical description or the law of Faraday's induction, what is the cause of physics? What causes electrons to move?)

Anyone knows the practical applications where nanofluids are currently being used. Many researchers have reported enhancement in heat transfer with nanofluid. But, nanofluids are currently being used for any practical applications?

we have a double-chambered MFC that produced an OCV that reached 220 mV in 1 h, and was getting higher. after 24 hours the OCV dropped down, and I don't know why.

I want to measure the generated current first to plot the I-V curve, then the power density curve.

- Is the OCV drop because we didn't use an external resistance? when should we start applying it to the MFC? can someone explain it in details please.
- How to decide whether to use a fixed resistance over time, or to use a range of different resistances to carry out these measurements (
*I-V*Curve, Power density Curve)?

I'm using a digital Multimeter for recording Voltage across either fixed or varied resistors.

Does any experienced such strange I overloads with Gamry 1010E (potentiostat is grounded), with cyclic polarization using Corrosion softver. Please see attached figure. Is there any solution to this problem?

Hello,

I am using a BLDC motor and I am controlling it with Field Oriented Control method.

I would like to tune my PI current and PID speed control loops but I don't know how.

Could you explain me how to do it or give me some links which could help me?

I have already searched but I am a bit lost.

Thank you in advance for your help.

In an expression of apparent power (S= VI*), why is conjugate of current considered?

The wire/cable in my chamber (for protein electrophoresis) was cut in half. I tried to re-join it by knotting the two ends. But the current still run unevenly among running wells.

I want to ask "

**what is the material makes up the wire/cable?**" so that I can try to weld it. The brand of the chamber is**Biorad**.I would appreciate any other suggestions to repair the wire/cable.

Thank you so much!

Can we measure currents of nano or pico amperes range reliably because I assume that normal lab multimeters won't work in this case because of their high internal resistances and noise. We get these low current values in simulation though but I couldn't figure out any method to measure such low current values using any instrument or any other method.

I have design the system in Matlab simulink, but when i start the current injection in the grid, my Source current become doubled also load current become less. I dont know this is active filtering or not.

Second, I am confuse about the PCC, when we inject current why the amplitude of the Source current changes,

Third, Can i keep the Vdc voltage of the capacitor initial voltage constant before start the simulation.

I would like to understand why if the secondary of a transformer is short circuited the primary winding will also reflect the short circuit despite the fact that they are isolated. Would the electromagnetic flux through the core be increased with a short circuit on the secondary? If the secondary is shorted I guess it would be as if no turns were present, there's no voltage difference. How would that draw more current from the supply at which the primary is connected?

For example a bipolar PNP diode without base electrode, if we sweep the bias from negative bias to positive bias, will this kind of device have current rectifying ability, why ? thanks!

The step is essential for further PIXEL calculations.

I am doing some corrosion study. For one of my sample I got corrosion potential 115 mv and corrosion current density 0.33 u A/cm^2, respectively, for same amout of exposure to 5% NaCl solution. According to ASTM C876 the threshold value for corrosion potential is 270 mv. And for corrosion current density it is 0.30 u A/cm^2. Which value should i consider as the sample is corroded as per corrosion current density threshold value but it is not corroded as per corrosion potential threshold value. I am a new researcher in this area. So, any help in this regard will be appreciated.

I'm planning to do research in area of vibrations. I want to know the gaps currently and do my bit too bridge those gaps.

I am using LiFePO4 battery, I measured DCIR using the discharge pulse. I found that the measured value of DCIR changes with respect to both pulse current and SOC. I provided adequate rest period before the pulse and after.

I dont understand the following behaviour. Could anyone give some hints to understand?

1. Why DCIR values are high at both low SOC (<30%) and high SOC (>90%)? I assume that the high resistance in low SOC is due to lower lithium concentration. What about high SOC?

2. Why DCIR value changes with pulse current? is it an error? Duration of the pulse, temperature remains the same.

Thanks in advance.

I am using potentiostat (CHI 660) to perform tafel analysis in three electrode mode, which can provide tafel slope for both electrodes and intercepts and corrosion current. There are different equations for determining (i.) exchange current density , however the simplified equation (attached) contain activation over potential or number of electrons (n). how to calculate these two parameters and exchange current density. The condition are double chamber fuel cell.

**Hello**

**I would like to measure electrical conductivity (resistivity) of electrospun fibermat of a polymer.**

**I know that:**

**Knowing the thickness of the fibermat, one should be able to apply it in the conventional test. Through this measurement, one can calculate conductivity through a correction factor by measuring the voltage and knowing the current applied.**

**The problem is:**

**Even when the lowest current value (2 nA) is applied, the instrument does not show enough stability of the current flow, and no voltage reading will be obtained.**

**What should I do?**

**I think the 4-point probe method is supposed to apply to semiconductor and non-conductor materials as well.**

**Does changing compliance help?**

**I am using one Keithley instrument as my current source and another one to read the voltage.**

**I would be grateful to have helpful comments.**

Hello! When I take the profiles of diffraction patterns from TEM images the minimum value at axis Y is at -Y, which really affects my results. (I have attached a picture which shows the above.)

Is there a technique I could use with Gatan so I can shift my results so the minimum point is at 0 on the Y axis? Or when I add two or more profiles together to compare them, they all start from the same point?

Thank you very much for your help and your time.

I’m currently working with those two vectors and need to check them via PCR, but I’ve been unable to find their sequences online so far. If anybody has them I would be really grateful if you can send them to me or direct me to an online source.

Thanks in advance!

What is the maximum distance of the conductor to transfer voltage and current from other conductor?

Hi colleagues,

What is the effect of increasing temperature in induction motor coil on the output current? Is a math formula can describe this relation?

thanks.

Anyone wants to cite their 'social entrepreneurship' paper in a detailed review paper currently in progress? Please share your paper/link. Social entrepreneurship papers specifically on emerging economies are requested.

how & why a reverse current occur in a circuit? what are the advantages & disadvantages of the current?

I am trying to control the speed and armature current of a shunt dc motor block in simulink, I am using one pi controller in the outer speed loop and the other pi controller in the inner armature current loop.

But I don't want to change the parameters of the pi controllers manually again and again. I want to use particle swarm optimization(p.S.O.) to do it, so that I can get optimal response.

Please suggest some papers or simulation files that probably include similar work.

I have a set of discharge current pulse values (Voltage vs Time) as well as Impedance Spectroscopy data of Li-ion battery. How could I transfer these pulses to frequency domain and fit with other impedance data. Any reference, papers, procedure will be very useful. At the end, I wanted to compare these results. Thanks

Dear all, i'm currently trying to make a survey to study the perception that have customers about labelled terroir products and i need help, could any one of you suggest me some relevant articles that will help me make a good survey. Thank you in advance

I have synthesized Co9S8/graphene nancomposite. I have measured CV of nanocomposites using three-electrode method in 6 M KOH. But I am getting very very low current and hence the Cs value. Also, I am not getting any pseudo peak of Co9S8 also. Do I need to change the electrolyte?? Please suggest.

To improve upon the existing SL Z source topologies (which are an improvement over classical zsource inverters but still possess inrush currents !!)and the existing soft start methodologies so that the inrush currents in the inductors at starting can be minimized in a contemporay z source inverter based ev drive .is it a potential problm for research ?? kindly give your valuable inputs .

As far as I know all countries are currently experiencing gerontogrowth, but not all countries are experiencing population aging. This is the case of Mozambique. Is there anybody investing this difference, besides obviously Gérard- François Dumond, as I acknowledge in a recente paper? see: https://authors.elsevier.com/a/1V4z3,oK5hcTAi

I'm looking for information about current tendencies in matter or Good Practices for the research stage of projects.

I am studying the Oxygen reduction reaction so i want to know that why reduction start from single point and then current goes on increasing as rotation increases.

What can best be used (Voltage, Current, etc.) to forecast harmonics?

I am doing research involving an online undergraduate-level introductory statistics course. The majority of our students are returning adults. It's been a few years since I've done any work in the field of adult education. What are currently the major theories that are being applied? When I was in graduate school Knowles' andragogical theory seemed to be big, but I'm not sure if that it still the case.

Studying the yearly load growth in radial distribution system system require realizing the maximum allowable currents in distribution networks to determine the maximum load growth rates?

I am currently working with GSOD Temperature time series analysis using R. I would like to ask suggestion on how to analysis temperature anomalies

I am researching on the rise of psychological assessments. Looking for any relevant statistics based on credible research regarding the same. Would like to understand what the current usage of assessments are, what are they mostly used for, what kind of assessments are most popular, etc.

I initially used the landsat gapfil extension in a different system and filled gaps, but the extension is not working on my current system. And I could not get a different data to mosaic and fill the gaps. Please help

Thanks in anticipation

Dear Sir,

Can you please tell me how to calculate power in watt from voltampere (VA)in Alternate current supply. Are we really need to power factor or can we just use Watt= volt* ampere.

Thank you in advance

In most of the voltage control loop applications, the input variables to a PI controller are reference voltage and actual voltage and the output is usually a current signal. How the controller converts the difference of two voltage signals to current signal?

how i can solve the error:the selected primary variable is not avvailable in the current frame in the abaqus

Hello everyone,

I have a little question regarding the current distribution over a slot antenna.

if I want to reverse the current direction over a certain location on a slot antenna, how can we do that?

Edge diffusion, anodic and cathodic currents, limiting current conditions

i am currently working on job performance of on-campus college working students. so far most of the researches available are into academic performance. any related literature that deals with such a concern would definitely be appreciated. thank you.

I am trying to measure the velocity of flow around the oyster farm.

depth of wáter is around 70cm or less.

I used every current meter from my lab.

one was i shouldn't stand near it and other one wasn't for ocean...

Transportation geography has undergone various developments since the mid-20th century, but does its traditional definition correspond to the current era? So what is the problem? and What definitions can be proposed?

What are the current hot topics in robotics? looking forward to your suggestions

Best Regards

I am asking in the context of capacity fade measurements.

Deciduous trees has increase and waterfowl has decreased in an already considered dry area

i want to know the latest or current issues in financial economics pertaining to sub-sahara African

Hello, i need to replace the currente medium growth for haematoccus for one with N-organic and P-organic (no animal origin)...Some one to know a nutrient that i can try.?

thanks

Currently, we are working on a moderated mediation model, and we want to test this model using smart-pls is it appropriate?

I am trying to measure galvanostatic charge discharge of supercapacitors by electrochemical workstation. It has three options to measure GCD; based on potential/ charging time or both. Which one should I follow to get the capacitance from the graph? What should I put for discharging current?

Hi,

Is it possible to use a photocathode which is currently used in photoelectrochemical cells, in vacuum?

Thank you in advance.

We are studying I-V characteristics of MIM structure. In this experiment, we observed that the current was decreased as the scan rate increased. Please tell me a possible reason for such behavior.

Thanks in advance !!!

Greetings,

Can anyone guide me as far as the most current standard in regards to the compressive strength of porous ceramics products?

In a three-phase asynchronous motorو No measuring sensorsو Knowing the characteristics of asynchronous motor,Voltage and current, How calculate speed?

Hello everyone,

I want to know the current factor affecting the RMS value of electrical loading of electrical machine. In most of the applications, sinusoidal current is applied to the machine. Therefore, RMS value is calculated as Arms=A(max)/sqrt(2). Does RMS value of electrical loading of electrical machine depends upon waveform of input current e.g. sqrt(2) is not used for square wave current.?