Devices to store chemical energy and convert it to electrical energy.

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15 views

Change in the EMF of the battery while charging

While charging a battery current is passed from A to B. We form the equation as follows- $$V_A - E - i_r= V_B$$ If the battery is discharged, how can we consider the EMF of the battery in this ...
2
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0answers
65 views

Circuit theory paradox - Unexpected results [closed]

I recently studied capacitors and found out that there is something called 'ideal circuit paradox'. Searching Google I found that one can cannot find the potential difference between two points in a ...
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2answers
39 views

Charging of a battery (reversing of polarity)

I wanted to know that how can we charge a battery using another higher voltage DC supply? I got a question that there is a 12 volt battery with an internal resistance 3ohm Connected with a 100 V DC ...
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0answers
32 views

Cells in parallel

Two cells of EMF 1.5V and 2.0V having internal resistances 0.2ohm and 0.3 ohm respectively are connected in parallel. Calculate the internal resistance of the equivalent cell.
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2answers
79 views

DC can be stored in batteries, while we cannot store AC [closed]

i have heard that direct current can be stored in batteries, but we can not store alternating current. is it true? if yes, then why?
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1answer
34 views

Is a real voltaic cell always schematically equivalent to an ideal battery and a resistor?

In the diagram I have attached, the top circuit is the schematic equivalent I am trying to use to model the middle circuit which uses real voltaic cells (that have internal resistance). I am not sure ...
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1answer
29 views

Is the $C$ rating of a battery a measure of Capicitance or Charge?

I have become confused as to the meaning of what a C rating of a battery means. My understanding is that because a C rating is measured in milli-ampere hours the units should cancel to be a unit of ...
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3answers
48 views

EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
4
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2answers
190 views

Will the two capacitors be charged in this circuit?

Is such a circuit possible to exist with the two capacitors charging? Because if we considered the outer loop using Kirchhoff's law we get: ℰ = q1/C1 + q2/C2 But since the two capacitors are ...
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2answers
63 views
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1answer
29 views

If a battery is open on one end but connected on the other, does it raise the potential on the connected end?

If a battery has one end open and other end connected to a circuit will the battery increase the potential at the point of connection?
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1answer
38 views

What is the work done by battery and what does work done on battery mean?

Suppose we have a charged capacitor connected to a battery. Now we push the plates of the capacitor away from each other decreasing capacitance and hence energy stored in the capacitor decreases. Now ...
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5answers
101 views

Brightness of 2 Lightbulbs hooked up to Capacitor [closed]

The figure shows a circuit consisting of a battery, a switch, two identical lightbulbs, and a capacitor that is initially uncharged. a. Immediately after the switch is closed, are either or both ...
2
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1answer
80 views

What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
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1answer
21 views

On a AC to DC adapter there are +12v wire with 24A and -12v have 0.5A. How many amp this adapter will provide in total? [closed]

I have a PSU of a pc which is 500w. I want to charge a 12v 100ah battery which need 20 amp of current. Is this psu can provide current that I have wanted? Main question is On a AC to DC adapter (PSU)...
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1answer
35 views

Charging of a battery

A battery has an Emf 6 Volts. It is completely discharged. It is charged by maintaining a potential difference of 9 Volts across it. If the internal resistance of the discharged battery is 10 ohms, ...
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4answers
107 views

Electrons moving in a simple circuit with a battery and a light bulb

I believe my understanding of electric currents is flawed and want some help to clear up a few things. I'm not looking for a precise scientific understanding, but to understand the basics. I'll try to ...
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1answer
57 views

What happens in the RC circuit when being charged?

Say I have this RC circuit and at the start, the switch is off (current going from left to right and the starting point is just above the battery). I understand that then the capacitor acts just like ...
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1answer
41 views

Adding two same DC voltage source in parallel

In a parallel circuit(imagine two branches),with one DC voltage in a branch and another DC voltage in a branch, what is the method of computing the total DC voltage? The voltage through each component ...
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3answers
200 views

Why electrons flow through a wire connected to a battery?

I would like to know why does electrons flow through a wire connected to a battery as said in AC/DC: What's the Difference?.It tells that "the electrons that are stripped from the carbon electrode is ...
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1answer
42 views

Do I need to “keep the electrons moving occasionally” in my laptop battery? [closed]

I read this: http://www.apple.com/shop/question/answers/product/MC556LL/B/will-it-hurt-my-macbook-pro-if-i-leave-the-power-supply-plugged-in-to-the-wall-socket-and-in-to-my-2011-macbook-pro-at-all-...
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1answer
40 views

How does a capacitor get charged while the charger circuit isn't closed? [closed]

a capacitor is a very known device in circuits that can be used as a short-time battery by charging it using another source, but how does it really get charged? if the plates of the capacitor don't ...
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1answer
63 views

Short circuit in superposition

I'm really confused about the concept of short circuits. I don't understand, why when you short those two voltage sources, 20 and 10 ohm resistors become parallel? What happens with 4, 12, 15 ohm ...
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2answers
143 views

Why does a battery die more quickly when more resistors are added to the circuit?

I will be explaining what I think: A battery acts like a pump which provides energy to do work on negative charges to move them towards the negative terminal, and hence creating an electric field. ...
3
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1answer
37 views

Does the internal resistance of a battery dissipate heat as expected?

A common real battery is often modelled (to a good approximation) as a perfect voltage source having emf $\varepsilon$ with a series internal resistance $r$. So, when a current $I$ is drained from it, ...
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0answers
16 views

How to calculate ion lithium battery voltage?

I have raw data from cyclic voltammetry test of ion-lithium battery. But I need nominal voltage or Open Circuit Voltge (OCV), like is reported in the literature. But I only have Voltage (V) vs ...
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3answers
310 views

How is Capacitance affected by a seperation distance and with or without a battery?

The questions specifically says this : A parallel-plate capacitor initially has capacitance $C$. The distance between the plates is then doubled, with a $9.0V$ battery connected. The battery is then ...
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4answers
119 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 ...
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1answer
36 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 ...
3
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0answers
38 views

What determines the speed of charging of a battery? [closed]

Recently we have seen the surge of superfast mobile phone charging. Just an example: http://www.bbc.com/news/technology-30708945 What underlying physical principle determines the speed of charging of ...
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0answers
43 views

What is the status of energy storing battery technology? [closed]

Most of electronic devices work off electric mains for short time (e.g., on smart phones - for a day or less). It is disappointing the solid state battery technology is moving slowly while othe ...
2
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0answers
29 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 ...
5
votes
1answer
121 views

Analogy in combination of batteries in series and pn junction diode circuit to find potential difference

Can I use the analogy of combination of two batteries to get the potential difference between two points(by applying Kirchhoff's law) in case ,if a pn junction diode is used in the place of other ...
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1answer
84 views

RC circuit discharging capacitor, trouble understanding

If we apply loop rule while charging the circuit we get: $$\varepsilon -iR-\frac{q}{C}=0$$ The way I understand, we follow trough the circuit just before the battery, as we move trough the circuit ...
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0answers
11 views

What is the distribution of a battery transmission?

I have an energy-harvesting battery attached to a node, transmitting data over Rayleigh flat fading channels. Energy in the battery is used, and simultaneously energy is harvested and stored. I want ...
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2answers
266 views

How electrical energy is transfered trhough a wire, and what's flow of charge?

I've read these texts about misconceptions about electricity. This is my understanding: Electrons do move, mut slowly and randomly. What happens is that, in fact, they're just 'conducting' the ...
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0answers
65 views

Internal resistance of a battery

It is my understanding that internal resistance of the battery is mainly due to resistance of its electrodes and electrolytes. During the charge or discharge of the battery, there's a potential drop $\...
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2answers
111 views

Battery and charge separation

In this question : What is the difference between a battery and a charged capacitor? http://physics.stackexchange.com/q/32394 It is said that the battery does not have a charge separation on its ...
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0answers
24 views

Setting up current directions in multiloop circuits with more than one battery

I'm currently working on this problem: I must find the current in each battery. I have certain doubts when estipulating the currents: How many $i$ exists in this problem? The current going in a ...
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1answer
54 views

Deriving Loop Equations in a Circuit with 2 batteries?

First time posting here, so please help with formatting. I need help deriving loop equations for this becaue the 2 batteries/power supplies are throwing me off. https://i.imgur.com/MJH6mIM.jpg The ...
2
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1answer
87 views

Given a large, multiloop circuit with resistors and batteries and I'm not sure how to simplify it. (When NOT to combine resistors?) [closed]

So here's the circuit, and the question is looking for current i: All resistors are 2 ohms and the batteries are 5 volts. I'm trying to apply the resistance combination Kurchov rules to make this ...
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1answer
69 views

Why magnesium is less reactive than lithium

Why divalent magnesium is less reactive than monovalent lithium? Intuitively second group elements should have lower ionization energy than first group but we observe opposite. For example magnesium ...
2
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2answers
106 views

Galvanic Cells and Electric Potential

In a battery or a galvanic cell, the electric potential of the battery is due to a difference of charges between the two cells like in a capacitor? So it is the electric field due to this separation ...
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votes
1answer
93 views

is it possible to use capacitors to quickly charge batteries? [closed]

the charging cycle of batteries is very slow compared to capacitors. Is it possible to use capacitors to quickly charge and discharge them to slow charge the batteries? For instance the range anxiety ...
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2answers
124 views

Battery charging a Capacitor

Ok I know there is a similar question already on here, but mine takes it just a step further. What I would really love to know is exactly how much energy is being transferred from a battery into a ...
3
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5answers
308 views

Why does not a battery kept in empty space discharge on its own? If space between the terminals is empty, what prevents the electrons to flow?

Given here is the picture of a twisted battery kept in free space (vacuum). Will the battery discharge quickly? I mean, it should discharge faster than it would if we were to connect the terminals ...
0
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0answers
40 views

What is causing a Li-Ion Battery to catch fire when it's not charging or powering anything?

I was just reading about UPS Airlines Flight 6, which crashed because of a fire in the cargo from Lithium Ion batteries. This is a case where the batteries were not powering anything and not charging. ...
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0answers
49 views

How to measure resistance of gel electrolyte using multimeter

How can I measure the resistance of a gel electrolyte using a multimeter? I know the formula to measure the conductivity of a gel electrolyte is k = (1/R) * (d/a) where k is the conductivity (S/cm), ...
2
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4answers
74 views

Many cells in parallel

If two or more cells of unequal voltages are connected in parallel (with the same terminal on the same side), is there a formula that gives the net potential difference? Also, by Kirchoff's loop law, ...
5
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0answers
319 views

Why chewing a battery increases its power? [closed]

I know almost nothing about physics. Last night my TV remote was not working. I chewed the batteries and woh! It still had power left. How does chewing a battery increases its power? I think it's a ...