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0answers
15 views

Natural timer project

I want to make a light bulb that is already on, turn off after a time that is as close as possible to 30 seconds. However, I can't use an electronic clock timer. Essentially, I just need to make two ...
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1answer
18 views

Accelerating Hard in an EV More Wasteful?

Is accelerating hard in an electric (or any, for that matter) vehicle any more wasteful than accelerating slowly? My flimsy grasp of physics suggests that it shouldn't be. The energy required to ...
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0answers
36 views

Why earth attracts electricity [closed]

Why earth attracts electricity? I am asking for earthing purpose, not of thunderstorm or atmospheric electricity. Do there is excess of electrons generated in an earth pit that attracts electric ...
1
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1answer
33 views

Kirchhoff's laws in phasor domain

While analysing AC circuits, we write voltage, current etc all with complex numbers namely "phasors". While studying the same, I wondered if Kirchhoff's laws held good with current and voltage in ...
1
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0answers
59 views

Can we construct a NOT logic gate without a transistor? [migrated]

Is it possible to build a NOT logic gate using discrete components without using NMOS or PMOS transistors?
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2answers
18 views

Electrical Insulators

I was wondering what happens to the electron after it leaves it's valence shell and strikes a stable valence shell; in an insulating material? I realize that the energy from the strike, is absorbed by ...
0
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0answers
14 views

Band-pass filter

In a multipoles bandpass filter assuming we have $n$ input poles (low cuttoff frequencies), which pole do we consider the critical low cutoff pole? The smallest or the largest? In other words after ...
0
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0answers
12 views

What is the physical mechanism of power transfer in the primary of an ideal transformer?

In an ideal transformer, the mutual induction caused by the secondary load current in the primary coil generates an additional current that has a non-zero power factor with the main AC voltage source. ...
0
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0answers
8 views

Can metal particles moving in high velocity combustion gas stream be charged

If we have a stream of combusted gasses in which there are micron sized metal particles moving at high speeds,can they be imparted a charge so that they move towards an oppositely charged target which ...
0
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1answer
52 views

What is time badwidth product for pulses with GDD?

For a gaussian pulse the time bandwidth product is dwdt = 0.4. What is the time-bandwidth product for chirped pulse with group delay dispersion (GDD) added only ?
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0answers
14 views

Why do ideal Op-Amps have zero offset voltage? [migrated]

Why does ideal operational amplifiers have zero offset voltage? Is that because it has infinite gain?
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0answers
22 views

Physics of the capacitance of an electrolytic capacitor

In explanations about the electrolytic capacitor one often cites the formula $$ C = \epsilon_r \epsilon_0 \frac{A}{d} $$ for the capacitance $C$. Then one says that by enlarging the area $A$ via ...
1
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0answers
43 views

Voltage and reactive power

Why are reactive power and voltage related? When the control system of a generator increases/decreases the current of the rotor, voltage and reactive power are increased/decreased.What is the relation ...
0
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3answers
43 views

Why fuse needs to be slightly more able to bear current than the appliance?

if I have a bulb with rated current of 4amps then why I need to connect an 5amps fuse?( which has slightly more ability to bear current.)
2
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0answers
18 views

Can seebeck chips be used to extract Peltier chip waste heat?

I understand that a problem with employing the Peltier effect for the purpose of cooling is that it produces a significant amount of heat on the hot plate. But why don't we use seebeck optimised chips ...
3
votes
3answers
130 views

What happens after an electron and hole combine?

OK so I understand that an LED is a pn junction where when a forward bias is placed across the junction, the electric field causes the electrons to combine with the holes and release a photon through ...
0
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2answers
28 views

Can an Oven being set to a different temperature cause electric board to go off?

Basically: the electrical system kept going off (when light goes down in a division due to too many electrical appliances on at a time, or their combined power consumption). My roommate said it was ...
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0answers
19 views

Which law of physics is applicable for communication? [closed]

What is the physics behind communication like internet, mobile phones etc. What are the equations?
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2answers
48 views

When heat loss is more than energy generated [closed]

Suppose a electric power station produces 200W of electricity @ 200V. Now instead of stepping it up, it decides to transmit it as 200V to a city 20 km away. The transmission cable has resistance per ...
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0answers
22 views

Separating Interaction of Heat from Electricity?

I have a rod where electricity of frequencies 1-360 Hz is passed through. It is affected by heat. I am evaluating the energy involved in such a process, contributed by electricity and heat. The ...
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4answers
91 views

Voltage of a battery in a circuit with an infinite resistance [closed]

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
31 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 [closed]

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
vote
1answer
50 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. ...
0
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0answers
24 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
26 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
62 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 ...
-2
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1answer
104 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?
11
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1answer
2k 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
18 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
votes
1answer
73 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
52 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
165 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 ...
0
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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
23 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
105 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 ...
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2answers
82 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
57 views

Reference for Kirchhoff's Circuit Laws

Does anyone know the reference where Gustav Kirchhoff published his famous circuit laws?
0
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1answer
58 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
70 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
votes
1answer
106 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
24 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
29 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
vote
2answers
98 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
vote
0answers
54 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
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5answers
4k 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
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1answer
41 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
93 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
185 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 ...