A battery is a power source consisting of one or more electrochemical cells with external connections for powering electrical devices such as flashlights, mobile phones, and electric cars. When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells, however the usage has evolved to include devices composed of a single cell.Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used for flashlights and a multitude of portable electronic devices. Secondary (rechargeable) batteries can be discharged and recharged multiple times using an applied electric current; the original composition of the electrodes can be restored by reverse current. Examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and mobile phones.
Batteries come in many shapes and sizes, from miniature cells used to power hearing aids and wristwatches to small, thin cells used in smartphones, to large lead acid batteries or lithium-ion batteries in vehicles, and at the largest extreme, huge battery banks the size of rooms that provide standby or emergency power for telephone exchanges and computer data centers.
Batteries have much lower specific energy (energy per unit mass) than common fuels such as gasoline. In automobiles, this is somewhat offset by the higher efficiency of electric motors in converting electrical energy to mechanical work, compared to combustion engines.
Hello to all, this may seem a very simple question but i can't work it out and have no clue where to start.
My question is: A 6v battery charges up a 470 microfarad capacitor in 1 second, what is the final charge of the capacitor? and what is the current while the capacitor is charging?
i...
Dear Experts
There are solar charging devices in the market for electronic devices.
These contain some electronics which I suppose is to regulate the power or as controller.
Lets say I have a 6 volts device and I have a solar panel rated at 6v.
If without any electronic controller...
hi guys.. I'm new here and this is my first post.. my friends told me that the title of this post is impossible and i need a car battery to heat the 800W nichrome wire, and i believe them.. they also said that AC will solve the problem.. but i need to use DC so i came up with using diodes.. the...
If there is a parallel plate capacitor, connected to a battery, which is then disconnected, there is NO voltage now, but "Q" (charge) on the capacitor remains the same. YES OR NO? I think yes.
I would like to know about selecting the proper lipo batteries. For example, for the following motor spec a suitable battery has to be selected
Motor Kv 540KV RPM/Volt
(What does KV in 540KV represent?)
Max Continuous Current 115 Amps
Max Continuous Power 4800 Watts
Max Lipo Cell...
Hi, I was doing some tests with lemon batteries today and found that it produced little current (not enough to light a small LED at least and I serially connected 4 lemons getting above 3V) which is explained in some places in the following way:
2 electrons are produced by the zinc (if your...
Homework Statement
Find the magnitude of the current in the 14V cell.
Answer in units of Amperes.
Homework Equations
Kirchoff's junction & loop laws:
I1 = I2 + I3
ƩΔV = 0
V = IR
Rseries = R1 + R2 + ...
1/Rparallel = 1/R1 + 1/R2 + ...
The Attempt at a Solution
At...
Homework Statement
For the circuit shown in the figure below, calculate the current I4 through the 1.94Ω resistor.
As shown, R1 = 4.05Ω, R2 = 8.11Ω, R3 = 6.17Ω, R4 = 1.94Ω, I1 = 2.97A and E1 = 12V
Homework Equations
V=IR
ƩI in a junction = ƩI out of a junction
ƩV in a loop = 0
The...
I have a phone. Since it was last charged, I used it for 8 hours and it was on standby for 16. Now my battery's down to 50%. How much battery did I use when I used the phone?
I'm thinking it's as simple as x + 2x = 50%.
Homework Statement
A Vbatt = 1.5 V battery stores Ubatt = 2.25 kJ of energy. I want to replace this battery with a charged capacitor that stores the same amount of energy and puts out the same voltage. That is, I want a capacitor such that UC = 2.25 kJ and VC = 1.5 V. What must the capacitance...
During one of my labs we were using circuits. I connected a 9V battery in parallel with a 2.kΏ resistor and a multimeter. I meaured the current across the circuit and noticed it went really high at the beginning (about 30mA) and then it slowly went down and the battery became really hot and...
Homework Statement
The circuit in the figure has a capacitor connected to a battery, two switches, and three resistors. Initially, the capacitor is uncharged and both of the switches are open.
(a) Switch S1 is closed. What is the current flowing out of the battery immediately after switch S1...
Homework Statement
How much energy must a 6.0 V battery expend to fully charge a 0.13 µF and a 0.21 µF capacitor when they are placed in the following configurations?
Another question if anyone can help we get started on this one. I'm not sure where to begin
How strong is the electric field...
Hi all,
I have a doubt regarding electrolytic capacitor. Why the electrolytic capacitor should be connected to higher DC potential in the circuit. What happens if the opposite happens? Also how electrolytic capacitors must be used where varying voltage comes across it?
-Devanand
I have taken apart a speaker set which uses a transformer to transform the 230-240v mains it receives into 9v AC 1A. I want to connect this circuit to a 9v battery. Nothing complicated-the standard Duracell one. Does anyone have any advice/comments on whether this will work or not?
Regards...
Homework Statement
A circuit is constructed with five resistors and one real battery as shown above right. We model. The real battery as an ideal emf V = 12 V in series with an internal resistance r as shown above left. The values for the resistors are: R1 = R3 = 30 Ω, R4 = R5 = 78 Ω and R2...
Homework Statement
A circuit is constructed with five resistors and a battery as shown. The battery voltage is V = 12 V. The values for the resistors are: R1 = 75 Ω, R2 = 127 Ω, R3 = 129 Ω, and R4 = 130 Ω. The value for RX is unknown, but it is known that I4, the current that flows through...
Homework Statement
A circuit is constructed with five resistors and a battery as shown. The battery voltage is V = 12 V. The values for the resistors are: R1 = 54 Ω, R2 = 142 Ω, R3 = 148 Ω, and R4 = 109 Ω. The value for RX is unknown, but it is known that I4, the current that flows through...
This isn't actually a homework/schoolwork question, but all the stickies on the other boards say that anything that is a school-work *type* question should go here. Not sure if this qualifies, but I figured I'd err on the side of caution. I took physics II last year and now I'm trying to do a...
If I had a big car battery and wanted to charge a smaller battery with it (say a laptop), how would I do that without breaking the laptop?
First of all, a battery has a certain voltage and DC current which is the same thing a laptop battery uses, but you'd have to ditch the AC adapter because...
Hi,
I am doing a project of making an electric car while using two DC Hub motors of 36V (750W power) each, one on each rare wheel. I intend to use a single Lithium ion battery of 48V and 32 Amph to operate both the hub motors.
Please tell me 'can a 48V & 32Amp Battery operate Two Hub...
Question for fun.
A car's battery is not a capacitor, but it seems to "accumulates" charge the same way. So, if you take a typical fully charged car's battery, what would be the equivalent capacitance of a 12V capacitor that would have the same charge?
For an extra kick - try to...
hi all,
I'm designing a hybrid motorcycle and want to select a battery for that. Can anyone tell me what will be the input parameter for the selection of the battery the motorcycle?
Hello everyone,
I'm trying to do a simple percentage change formula to analyze the difference that a material change can have on a battery and would just like some advice as to whether or not I proceeded correctly.
Essentially, my reference text gives an example of a Battery whose cast...
Hello:
I have a basic query, regarding the charging and usage of battery.
When I charge a battery it needs some energy, say 100 watt. Does the charged battery now will provide me back 100 watt (or more or less)?
My confusion is specially due to, we use invertors in most of the places to...
I'm working on a project that has a 7.4v rechargeable battery pack and I am going to recharge the pack with a solar cell. If the solar cell is only capable of outputing no more than about 2v, is it at all possible to charge the battery pack?
Thanks!
There's three lamps in a series circuit, which are rated 0.05A, 6v. What size of current will be drawn from the battery pack. Explain why this is.
You need to please reply quickly. I've got lots of homework to do still and it's 9.00pm nearly.
Sorry for being a bit impatient, but I really...
Hi
I have a wish to "create" a battery that I can use as replacement for a regular power adapter. Main reason I want to do this is to get something that will be mobile with my PC (HP Touch Smart)
Input: 100-240, 2A, 50-60 HZ
Output: 19V, 7.9A, 150W
What technical solutions am I looking...
Homework Statement
Which of the following batteries has the most stored charge? Their ratings are shown below. Explain your answer.
a) 12V, 500mAh
b) 1.2V, 1200uAh
c) 6V, 3.14159x10e17 electrons
d) 6V, 0.01MAh
2. The attempt at a solution
I think the answer is d because 0.01MAh = 10,000Ah...
I'm trying to charge my cellphone and would like to know how many volts would cause the cellphone battery damage? Also, how many amps would an average phone need to be charged?
Hello every one:smile:
I would like some help regarding building a battery powered heater.
Let me describe the problem first
I shoot air rifles as a hobby and am restricted to 12foot pound of muzzle energy here in the UK
One of my rifles that I prefer to shoot is CO2 powered...
Can anyone tell me how to wire a momentary normally open switch to a battery operated device (4 AA batteries) like this one? http://www.scientificsonline.com/mini-plasma-ball.html
Is it even possible? Any advice appreciated!
So I have an idea and was wondering if anyone here could help me understand some of the physics behind trying to make it work before I buy up some materials and experiment. All the google searches I did with various keywords kept hitting here so...
I have a battery, let's say it is 7.4V and...
Hello forum,
a battery is a voltage source: it provides constant voltage, regardless of the load connected to it.
there is also a current source: it provides constant current, regardless of the connected load.
Is there something like a power source, something that outputs constant...
While I was looking at an example of the Biot-Savart Law for a finite, straight wire of current, I started considering whether one can easily create one in practice.
If I hooked up the positive terminal of a 9 V battery by a resistance to the negative terminal of another 9 V battery, would...
What is the speed of electron flow in an eletric curcuit? A battery (cell) with a copper wire shorted across the positive and negative posts. What will the electron flow be through the copper wire?
Homework Statement
Obviously I do not believe this to be the case, but when running a car the battery is I assume having current drawn in, reversing its normal means of depletion so that the potential chemical reaction can take place later on. My question is when you turn on the radio while...
Well i couldnot help out with the concept that conventional tubes for x ray production require high acceleration voltages in the order of kVs but how a portable XRF produces x rays with a rechargeable battery ?? Does it produce high enough accelerationn pressure, i have some doubts or there is...
This would be fun to know. So, if I need to leave my house quickly, is it worth it to throw my dead phone on the charger for 10 minutes because that initial charge time is the most efficient, or is charge a linear relation with time?
Homework Statement
A battery with voltage V=12V is connected to the primary of a transformer. A resistor with resistance R =20 Ohms is connected to the transformer secondary. The transformer has an iron core with Np=200 turns on the primary and Ns=600 turns on the secondary. Assume the...
Homework Statement
so the problem, along with the figure, can be found http://www.cramster.com/answers-nov-09/physics/problem-3268-12-car-battery-dies-somuch-volt_697332.aspx?rec=0
Homework Equations
I=V/R,
The Attempt at a Solution
I am able to calculate parts a and b...
Hi
I have what seems to be a untractable problem
On a racing motorcycle I am using a total loss ingition/datalogging and water pump system. To power this I am using a 5000Ma 30C LiPo battery (used because of it light weight and small size). The measured battery output is 15.2 Volts. Both the...
Hi all,
I am trying to determine what is the maximum number of amps I can charge 4 batteries that are in parallel and series ( 4x12V batteries) to produce 24 volts.
I have the specs on the batteries and everything but can not seem to determine how many amps they can handle when being...
i would like to design a solar assisted driving mechanism for my bicycle?
What is the compatible battery specifications to power 24v 1hp dc motor and the necessary solar panel specification to charge the battery? I'm kinda clueless in this so any help would be deeply appreciated. Thanks
Hello all.
I am in the process of designing a circuit that involves a resistor divider that connects to a buffer to be connected to a DAQ system. This circuit is being made because the input voltage coming in will be in the range of tens of volts, and what I want is a smaller Vpp wave...
Homework Statement
A 10.0 uF capacitor is charged by a 10-V battery through a resistance R. The capacitor reaches a potential difference of 4.00-V in a time interval of 3.00 s after charging begins. Find R.
Homework Equations
C = Q/ΔV
q = εC(1-e(-t/RC)
The Attempt at a Solution...
Please help! Also, please correct any misunderstandings which I have. I have read about electricity basics and what happens on the atomic level until I have read ideas which compete with each other.
1 - I've read that the word electricity applies to particles with a negative charge (more...
Hi. I'm investigating the idea of using a laptop battery for energy storage in a portable solar setup. The idea is charging the battery from solar panels, then power/charge other devices from the battery in low light conditions.
I would like to be able to power/charge laptops and...
I am working on a senior design project that is to design a battery management system to monitor NiMH batteries powering an electric truck. The professors who proposed the project set the main requirements to be that it measures the voltage of every cell, the temperature of every 5-10 cells and...