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1
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2answers
36 views

Voltage of a battery in a circuit with an infinite resistance

I have a dilemma that I would like to share with you concerning batteries (without neglecting internal resistance), emf and resistance of a circuit. To better visualize my question you may need to ...
1
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1answer
22 views

Estimate battery's real capacity in real time [duplicate]

The maximum capacity of a battery during usage can vary from manufacturer's specifications due to factors like temperatures and battery health. Because of that i want to estimate the real maximum ...
1
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0answers
21 views

Electron , collision , current , dual nature [on hold]

My question is regarding fundemantal concept. I am good in kcl and kvl delta to y resistor rcl and rl circuits machines etc but as i read drift velocity i get so many questions. We are reading since ...
1
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1answer
40 views

Will an Electrical Engineering Minor give me a significant advantage in experimental physics? [closed]

I'm currently choosing courses to complete in my university degree (science) and thought completing some basic electrical engineering may be useful if I go into academic experimental physics research. ...
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0answers
20 views

Books on Spectral Jacobian

Can anyone point me a book to better understand "spectral Jacobian". I am studying X-parameters, I have the book X-Parameters: Characterization, Modeling, and Design of Nonlinear RF and Microwave ...
2
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0answers
20 views

Estimating the battery capacity using current power consumption and battery percentage

I want to estimate the current maximum capacity (in kWh) having the current power consumption (in kWh) and the state of charge of the battery (in %) available in a time series. I do not have a full ...
1
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1answer
59 views

Why do scientists measure fundamental constants so precisely?

According to the last CODATA report the charge of electron is measured very precisely (10 decimal places). And it's not only about the charge of electron. Why do scientists measure fundamental ...
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1answer
77 views

Why does the symbol have an arrow? [closed]

What does the arrow in the symbol mean? Does it mean that it is a variable voltmeter and ammeter?
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1answer
1k views

Why don't they use springs as an energy source for cell phones?

I know they used springs for clocks way back in the day and now it's all lithium ion batteries. For reference, consider the Iphone that has a battery with a capacity of 5 Watt hours (18,000 joules). ...
1
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1answer
16 views

Why current of a battery drops continuously in high currents?

I have asked this question on EE SE but could not get a satisfactory enough answer. I have shorted an AA battery through an ammeter. Inititially, the current reading on ammeter was around 0.9 amperes ...
0
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1answer
57 views

Laser-induced electrical discharge

Attracting lightning with an ion beam has been done in a lab but how strong of a laser is needed to reach the clouds to redirect the lightning bolt?
2
votes
1answer
37 views

Why does small change in Base current causes a larger change in collector current in case of transistors? [closed]

Why does small change in the base current causes larger change in the collector current. That is say if I increase the base current buy a small amount why the collector current increases by a very ...
0
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0answers
57 views

Exact (quantitative) definition of “knee” and/or “cut-in” voltage?

Sort of a 2-part question: 1) I know they are used interchangeably but are the "knee" and "cut-in" voltages of a diode actually the exact same thing? I had thought that the "cut-in" voltage was ...
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2answers
44 views

Electricity from something other than a solid

Is piezoelectricity only limited to solids or can liquids or non-Newtonian fluids create a current when compressed?
0
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0answers
22 views

how to reduce the order of the hamiltonian equation for electrical problem given below?

I am having my FYP in this Hamiltonian project to analysis the integrator for Hamiltonian system. Can anyone please guide me how to reduce the equations to first order using substitution method?
0
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0answers
21 views

How to reduce the order of Hamiltonian equation for electrical problem [duplicate]

I want to reduce the order of this Hamiltonian but I don't know how to proceed. The equations are given below: $$H(p,q) = \frac{1}{2} (kq^2) + \frac{p^2}{2m} $$ This is the Hamiltonian for a simple ...
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0answers
60 views

Designing Repelling Electromagnets [closed]

I need to design a pair of electromagnets to repel each other with maximum force while being less than a certain weight. Specifically, they must accelerate a a 1lb mass to 5 m/s vertically within 5cm ...
1
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2answers
63 views

How many photons does my remote control garage opener emit?

Every time I drive up to my house I imagine all the photons spitting out of the remote control garage opener when I press the button. And I imagine the door opener in the garage receiving them. There ...
1
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1answer
45 views

Reference for Kirchhoff's Circuit Laws

Does anyone know the reference where Gustav Kirchhoff published his famous circuit laws?
0
votes
1answer
44 views

Attenuation and Amplification - Transatlantic telecommunications cable system

It's a german book so I don't know if I'm translating this properly into english, so bear with me: The TAT-14 connects the cities Norden and Tuckerton with glass fibers (~7500 km). The cable has ...
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0answers
69 views

Higher dimensional, generalised theoretical digital electronics

I'm learning digital engineering and I'm also a fan of theoretical and abstract physics and mathematics. I find it amazing that you have an algebra that directly corresponds to logic circuits and if ...
0
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1answer
62 views

differentiate between v(rms) and V(avg/dc) of an Ac signal [duplicate]

Please differentiate between v(rms) and V(avg/dc) of an Ac signal . Why do we use rms and why is vrms called effective value; why is vp not so called or (v(avg))? And why we use v rms to calculate ...
1
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0answers
18 views

Weight handling capacity of motors [closed]

I am a student of final year electronics engineering at University of Pune. Our project is PLC based sweet manufacturing machine. In this device, we are using a mould which will be approximately 1 kg. ...
2
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0answers
26 views

How to mathematically model a realistic aperture illumination?

I want to know a mathematical expression that I can use to model a realistic aperture illumination to produce the primary beam of an antenna so that the radial distribution of this aperture ...
1
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2answers
51 views

diffusion velocity

i understand that diffusion is the movement of particles from high concentration areas to low concentration, but what is the cause of that movement atomically. And especially in the case of charge ...
1
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0answers
47 views

Acquiring an Active Q-Switched Laser

I'm working on a senior undergraduate project in engineering physics, and I am building an instrument that will use a Q-switched laser as a short-pulse, low-pulse-repetition-rate light source. We need ...
2
votes
3answers
1k views

Difference between live and neutral wires

In domestic electrical circuits, there are 3 wires - live, earth and neutral. What is the difference between the live and neutral wires? As there is AC supply, it means that there are no fixed ...
0
votes
1answer
35 views

Flow of charges in two different materials

Consider two cylindrical conductor rods as Copper rod and aluminium rod. Their edges are in contact,that is their circular faces are in contact. Their other edges are connected to some DC voltage. And ...
2
votes
1answer
57 views

How to make electrical connection to silicon wafer for testing?

I am trying to make an electrical connection to a silicon wafer using a wire (approx 32AWG). I find that conventional lead/tin (60/40, no flux) solder cannot adhere well to the silicon wafer, since ...
2
votes
6answers
129 views

Current when resistance is 0

A short circuit has $\rm 0$ resistance. We use Ohm's Law $\rm V=IR$. If $\rm R=0$, then $\rm V=0$. Doesn't this mean $\rm I$ can theoretically be anything? Thus $\rm I$ can be like $\rm35A$ for ...
0
votes
3answers
42 views

How to conserve energy with electrical noise?

If a resistor experiences thermal noise, it will dissipate energy to the environment. But where does the resistor's energy come from? It seems that it will just lose energy until ran out.
0
votes
1answer
69 views

Why do electrical storms cause metal objects to vibrate?

I am curious about the vibration of metal objects as a sign of an impending lightening strike. This is apparently a common occurrence; so much so that a quick google search will yield many pages ...
0
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0answers
74 views

What is the smallest possible electronic transistor?

Computers have increased in processing power mainly due to the miniaturization of transistors. I read recently that IBM, with great difficulty, shrank circuits from 14nm to 7nm but progress seems to ...
0
votes
0answers
77 views

Why the rotational speed of a simple single-coil DC motor will increase as the number of turns in the coil increases?

I am working on a report about a simple DC motor. I have known that the speed of a DC motor is directly proportional to the applied voltage. However, based on the data collected, why the speed of the ...
1
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2answers
43 views

How do you model the resistance across a symmetric sheet of plastic, streched (think ceran wrap) between a circular anode and cathode?

Here is the problem. You need to model the resistance across a circular sheet of polypropylene (plastic). The resistivity of polypropylene is 1E15 Ohms per meter. The expression for resistance on a ...
1
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0answers
207 views

Negative resistance temperature coefficient of metals

How is it explainable that some metals have their electrical resistance increased while other metals act the other way? When the temperature of a metal rises the molecules move faster and from my ...
0
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1answer
64 views

What happens if the load on the electrical generator exceeds its generation power ? and why?

What happens if the load on the electrical generator exceeds its power generation?and why?
0
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0answers
95 views

How to calculate electrical and thermal conductivity, enthalpy and density of plasma column in air for a series electric arc?

I am modeling an electric arc according to "Lowke's Simple theory of free burning arc". Its a very interesting theoretical arc model and I want to implement it in Matlab/Simulink. But here, the arc ...
3
votes
2answers
130 views

Why is the electric field highest in regions of highest resistance?

I know Kirchhoff's law and that current must be constant. But what exactly is the phenomenon, from first principles, that causes the electric field to be stronger in a region with lower carrier ...
2
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3answers
77 views

Does the equation CV = q break down when V is small or a wire is very long?

I'm trying to understand how the equation $CV=q$ relating the voltage difference and charge stored on a charged capacitor breaks down under extreme circumstances. In most problem statements that I'm ...
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0answers
37 views

Help with finding an equation to work out the length of cable required to produce loss of colour on an analogue video signal

When I briefly taught Broadcast Engineering I set up an experiment in order to demonstrate the effect of signal reflections along coaxial cable on an analogue PAL waveform. It involved getting the ...
0
votes
1answer
89 views

How long can a cellphone battery(pictured) power a LED light that produces light equivalent to traditional 60W bulb(800 lumens)?

Assuming Energy Star rated LEDs which produces 100 lumens/watts. Battery rated as 9.88Wh. Power consumption by LED = 800 lumens/100lumens/watt = 8 Watts Does it mean that it will power circuit for ...
0
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0answers
29 views

Would touching a bimetal probe short a nichrome wire heater?

Long story short: found electrical equipment box to play with. So would trying to get the temp of a heated nichrome wire with the use of a k probe short the nichrome? (k probe touching the wire) And ...
2
votes
1answer
33 views

In a noiseless environment, how accurate do today's transmitters send EM waves?

Suppose that there is no external noise in the environment. How accurate are today's TEM wave transmitters in such a case? So if we want to send $200\cos(1000\pi t)$, can transmitters send exactly ...
0
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0answers
50 views

Why does a field-effect transistor (FET) with wrap-around gate work at all?

In the recent years several publications have presented field-effect transistors (FETs) that are based on semiconductor nanowires with a gate electrode that is wrapped around the whole nanowire ...
0
votes
1answer
48 views

What is the difference in the behaviour of the commutator in a motor between DC and AC?

Is it correct to say that in DC, the split ring commutator produces direct current flow and therefore stronger voltage, as opposed to AC which produces alternating current and therefore weaker ...
-1
votes
1answer
218 views

What device is best to prevent electric motors from burning out? [closed]

Is there any equipment to prevent electric motors from burning out? I have researched about Transient voltage surge suppressor TVSS and also Surge protection device. Can this help?
1
vote
1answer
37 views

Stability of an unstable system using nonlinear element, is it possible or not?

Say there is a system with open-loop transfer function $$ G(s)=\frac{1}{(s-1)}$$. The system is definitely unstable. If I put any nonlinear system in cascade with $G(s)$ and from the output, a ...
0
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1answer
34 views

There is some attempt to build a magnetic flywheel (reservoir of motion)

We know how flywheel works! There is some attempt to substitute the flywheel-friction mechanism for some magnetic torque ? Exist some mechanism that uses thermal cycle of gases for generate magnetic ...
0
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0answers
29 views

Holding a photolithography mask (EUV litography) with magnets, to minimize deformation on the photomask?

Some background: what is this question about? On 20/11/2014, I visited the ASML Holding in the Netherlands, which is according to them, and according to Wikipedia: the largest supplier in the ...