Charging Definition and 407 Threads

Homework Statement A scuba diver's 2ft3 air tank is to be filled with air from a compressed air line at 120 psia and 100F. Initially, the air in this tank is at 20 psia and 70F. Presuming that the tank is well insulated, determine the temperature and mass in the tank when it is filled to 120...

Is it technologically possible to improve the speed of these machine's charging? I mean, I want to go now for a walk, but it seems I need to charge my phone for at least 30 minutes, can we lower the expected charging time? What obstacles do we find to overcome this? Thanks in advance, MP.

Homework Statement A 10-cm-diameter parallel-plate capacitor has a 1.0 mm spacing. The electric field between the plates is increasing at the rate 1.4×106V/m*s. What is the magnetic field strength 2.7cm from the axis? Homework Equations \ointB*ds=\mu\epsilondE(t)/dt*A...

A solar panel have a certain voltage at which it produces the most power. Below this voltage it's a current source - giving about the same current all the way down to short circuit. Right? On the other hand, a capacitor sucks up as much current as is available (ignoring ESR), slowly...

I am confused about how to find the electric field between a discharging capacitor. For example, let's say I have a fully charged capacitor, such that there is no current flow anywhere. Then there is an electric field between the capacitor which equals 2*sigma/epsilon_0. But now the...

I am redeveloping a product that literally billions of people use, from every day to at least once a month. I need some help designing the power portion, as I am not an engineer. I am planning on using the GTL ICR18650 3.7V 3000 mAh Lithium Battery because it provides the power needed, as...

I have a very small project which requires a typical 9v battery for mobile use. But to keep from having to replace the battery I would like to put in a rechargable 9v battery and use a 9v output from a dc power plug to charge it. I have charged batteries with solar panels before and all that is...

Hello all, I am new here. So you see where my lack of understanding comes from; my background is as a Mechanical Engineer and I'm currently in my masters year. I haven't touched electronics since A levels but I was hoping somebody could point me in the right direction. These forums tend to...

Can anyone help me by discussing the charging and discharging methods of ordinary acid batteries which are used in inverters, cars etc and that of the dry cells in detail? Please give me any link where these methods are elaborately discussed.

I am trying to charge a system of two metal rods, of definite length, placed a certain distance apart. But before setting up the rods and hooking them to any battery, i wish to know the magnitude of charge that will be accumulated on the rods and what is the maximum possible charge on the rods...

Homework Statement Hi all, My question is: In what kind of device the enclosed schematic can find an application? The bipolar switch has two positions U and u- which are for upper position and D and d- which are for down position. The main question is on what kind of equation the voltage...

Hello I have a conceptual question about using Kirchhoff's voltage rule to derive expression of the charge in the RC series circuit when it is being charged by certain EMF. Usually most books start by writing the equation \mathscr{E}-iR-\frac{q}{C}=0 But when the charging is going on...

Homework Statement A capacitor is charged up to it's maximum charge capacity. Once it's reached it's maximum charge capacity, a switched is open which isolates the charged capacitor in a circuit of it's own, containing itself and a resistor (The emf used to charge the capacitor is no longer...

Hi, Consider a charged capacitor connected to a an empty capacitor. The charged capacitor starts to discharge while the empty capacitor starts charging. The whole process finishes when the two capacitors maintain the same potential difference. The problem is that when calculating the energies...

Homework Statement Switch is initially opened with the capacitor uncharged. At t=0 the switch is clsoed. At time=t1 later, the potential difference between A and B is 2.00volts Find the charge on the capacitor at time t1. R=10,000ohms C=2.4nF Vb=12volts VA->B-=2.00volts Homework...

Should I drain my battery on my Nexus before charging it again?

How we calculate the duration of depositing a specific amount of charge via a battery on a pure Capacitor when resistance is not present..and we can't use the formulas of RC combinatio?

Maybe somebody can help me with the following question on batteries: I have several batteries which I have to charge from different sources. I have solar panels on the roof of my RV, 2 by 3 meters. On a sunny day, they can charge maybe the equivalent of a 100 ah battery. But if I run...

Hello friends, I am performing an experiment and need a charged fluid here are some questions I have, hopefully someone can help. Can I create a charged fluid by taking distilled water, then adding NaCl (positive and negative charges), and then immersing the positive end of a voltage...

I am working with a hybrid car which charges a bank of ultracaps from regen braking. I read an article which I believe was written by someone who is misinformed, but it had me thinking... Just to clarify some theory about charging voltage, Scenario Max ultracap voltage= 14V Current...

Hello Forum, Battery chargers are devices to put energy into a secondary (rechargable) bttery by forcing an electric current through it. The charge current depends on the technology and capacity of the battery being charged. The capacity of a battery represent the amount of electric charge...

Hello, I have a question that I hope someone here can help me with. In all of the descriptions about induction charging and grounding, the incoming negative charge is depicted as being applied to one side of a neutral, uncharged object. If I understand correctly, according to the law of...

Can I ask how long a dynamo of 12 V, 6watts to charge a 12 V, 100 Ah battery? And by connecting the battery to a air compressor working on 1.2 hp and 12 V, max amp draw = 18Amps, how fast the battery will become flat?

Homework Statement Homework Equations C=Q/V. T = RC The Attempt at a Solution Capacitance is found to be 334.6217 picoFarads (from previous part of question) When input voltage is high, capacitor is charging (falling pink line), then...

Homework Statement A 2600-nF capacitor is disconnected from the 15-V battery and used to charge three uncharged capacitors, a 100-nF capacitor, a 200-nF capacitor, and a 300-nF capacitor, connected in series. After charging, what is the potential difference across each of the four...

Hey. Was jump starting and charging a car battery a couple of days ago for the first time. I connected the positive of the bad battery to the positive of the good battery, then connected the negative of the good battery to a solid metallic, non-painted part of the engine on the bad car, or the...

I know that AAA batteries (and batteries in general) provide a very low continuous current due to the chemical reaction. Is it feasible to charge a capacitor of say 25F (yes F not μF) from AAA lithium batteries...

Hello everyone! First post, so I apologize if I am in the wrong area. I am designing a charging circuit for a project, but I don't have much experience with power electronics. The circuit must output 3.3V and be rechargeable through the use of a USB power supply (5V DC). Here is what I am...

I am from a country where power outage is very common. I have a light source which is run by a lead acid battery. At night, I want to keep this light ON during power outage and when the electricity is back on, the charging circuit engages and the lights should turn off itself. I am guessing an...

Homework Statement Solving the equation: V = V0*[1 - e^(-t/RC)]Homework Equations Need to solve this equation for time to calculate the time at which a charging capacitor achieves a certain voltage across it's plates.The Attempt at a Solution I solve it as: t = -RC*ln(V/V0) but this doesn't...

http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/files/29/1823/figure_01.gif So let me just start by saying that, I want to understand how to analyze circuits and I would like to find a good source for that. If some one could point to online...

I am new with the topic Capacitors .I have read that a capacitor can be charged in two ways .One using the battery which I understand .The other is by charging one plate and grounding the other plate .I am not able to understand how this is done . Suppose +q charge is given to a plate ,say...

Here's the scenario: I need two plates that start off in proximity (a few mm apart), and I would like to vary the charge in these plates to achieve a repulsion force. Ideally it would be varied by a voltage source, so that I have fine control over the repulsion. But as it happens, it is not...

Hello, I've just got a quick question about charging an object by conduction. I've been studying for my final and I came across a problem that I can't really see how to solve. Say you have two conducting spheres, A and B. They are both exactly the same in every way except for their electric...

Hello All, Could you please explain what would happen if I charge a capacitor with say 30 khz DC 500 volts with a 10000 uf cap. Would a gas discharge tube, varistor, triac of 300 volts connected across the capacitor help to preventing it from exploding? Ged

Homework Statement Circuit as shown below. At what voltage of E does the battery begin to charge? What percentage of the power is delivered to the 1R resistor by the voltage supply E when the charging current is zero? What is the current through the battery when E = 20V...

Homework Statement Consider the circuit below, where C1=80mF, C2=30mF, R=50ohms and E=5V. At t=0, both capacitors are uncharged - so it's charging. The circuit is in series, with E ---> C1 ---> C2 ---> R ---> (back to) E a) Find the time constant. b) The initial potential...

Please see the attached photo. I am not sure how to proceed. I do not know Mi or M2, nor do I have enough information to determine the temperature at point two (when the valve is closed). Any help getting me going along will be much appreciated. :)

Homework Statement If a body is charged by rubbing it, its weight a) may slightly increase of slightly decrease b) increases slightly c) decreases slightly d) remains constant Homework Equations The Attempt at a Solution I know weight is nothing but gravitational force...

Hello Everyone, I need to solve this problem: How many seconds does it take to charge a 7.7 x 10-7 farad capacitor to 70V if it is initially uncharged, then connected to a 190V battery through a 11000 ohm resistor. What I have so far: q = CV q = (7.7 x 10-7f)(70V) q = 5.39 x 10-5C q...

Good Afternoon, I'd like to build a wireless charging circuit from scratch, but I am unsure of where to start. Every time I attempted the experiment the coils would not transfer power and I am unsure of what I am doing incorrectly. If anyone could point me to a resource for DIY wireless...

Hi I am fairly new to electronics and I have a project I want to create a circuit for. I have a solar panel rated 6v 50mA. I want to make a rechargeable battery run a series of 2 or 3 bright LEDs. My question is: What voltage limit will the source need to have in order to take a charge...

I had a few questions about circuits. I am a mechanical engineer so I don't have very much knowledge in electrical theory, just basic stuff, but I have been working on some basic circuit design and could use some help. I have three questions really. So I have a 3.7V battery on a device...

The circuit shown in the attachment is a clamper circuit. I want to know that during the first half of the positive input cycle the capacitor charges through the diode, but as soon as the capacitor starts charging its left plate will become negatively charged so it should make the diode reverse...

Not your typical Electrical Engineering post I'm sure but there is so much misinformation out there and I'm sure there would be some interesting applications for others here. I'd like to be able to charge not only my current laptop (standard Gigabyte 15 inch) and phone (HTC Desire) but future...

Homework Statement I would like to derive the equation Vc=Vss+(Vi-Vss)*e^(-t/RC) Vss is the steady state voltage Vi is the initial capacitor voltage Vc is the capacitor voltage The Attempt at a Solution I tried to find solution using laplace transform. E=iR+1/c∫idt. Taking laplace...

I understand that Amazon don't give you a charger with the new Touch. I have read on (very non-tech) forums that there are 'issues' when trying to charge a Touch, with the Orange light coming on unexpectedly and uncertainty whether the thing is charged in fact. Does the Touch charge via a USB...

Homework Statement An insulated spherical conductor of radius R1 carries a charge Q. A second conducting sphere of radius R2 and initially uncharged is then connected to the first by a long conducting wire. (a) After the connection, what can you say about the electric potential of each...

I am wondering how can an alternator charge the battery if the rpm change constantly? Can someone please explain me how it manages to produce a constant voltage?

Hi guys (and gals) Say, i have a solar panel rated at 100w 12v with the following specs: Short circult current(Isc): 6.01A Open circuit voltage(Voc): 21.5V Optimum operating current: (Imp) 5.52A Optimum operating voltage: (Vmp) 17.78v Maximum power: (Pmax) 100W And I decide to...