Charging Definition and 402 Threads

Homework Statement Hi I have been told that the question below might be similar to potential university interview questions for physics/electronic engineering. In relation to this circuit diagram: http://forum.allaboutcircuits.com/attachments/diagram-ac-diode-capacitor-pd-question-png.90713/...

Hello Forum, There are three types of objects: conductors, insulators, and semiconductor. Let's leaves semiconductors aside for now. --Conductors are said to have a very large number of free charges. Neutral conductors can be electrically charged (either positive or negative) either via contact...

I understand the situation when we charge a capacitor using a battery and a resistor placed in between serially placed ! V = iR + Q/C where we write i = dQ/dt whereas, V is voltage of battery R is resistance of resistor Q is charge on capacitor C is capacitance of capacitor i is current But what...

Hi, I have just got into the battery industry and i would like to understand a few things especially when it comes to sizing a battery. For example: if i have a load of 1600W and the system voltage is -48V DC (for a telecom application). The main supply is AC which is converted into DC through...

Homework Statement A 3.00 MΩ resistor and a 1.00 μF capacitor are connected in series with an ideal battery of emf E = 4.00 V. At 1.00 sec after the connection is made, what is the rate at which (a) the charge of the capacitor is increasing; (b) energy is being stored in the capacitor; (c)...

Hi, I'm trying to build a capacitor charger that can charge a capacitor to a higher voltage than the battery voltage I have. When reading up on charging capacitors, the simplest method seems to be wiring something similar to the capacitor charger for a camera flash. Unfortunately, a camera flash...

So I learned that outlets actually provide a lot more voltage than small electronics like phones need but that transformers are used for voltage optimization. Is the sole reason that this is the case is so that the battery generates less heat and doesn't affect the battery as much? Or is there...

First off, I am a ME student, and I only know enough about electricity to get myself into trouble. I am looking to build a flashlight using a 100w LED chip, a step up constant-current transformer from 12V (or 24V) to 34V and either one or two 12V batteries (higher voltage to improve efficiency)...

When a body is postively charged q and another uncharged body is touched to it what happens to both the bodies...why and how is charge distribution...please explain

This question was taken from the public examination in my country/region. The answer from the marking scheme is, only statement 1 is correct and the others are wrong. Can anyone explain why the other statements are wrong? 1. Homework Statement The following components are connected in series...

I need some clarification on batteries and capacitors. Before a battery is connected to a capacitor, the capacitor is uncharged. When a battery is connected, an electron from one conductor moves toward the positive terminal of the battery, leaving this conductor positively charged. What causes...

Hi, I would like to know if it is possible to charge some batteries in this case: 4W output power, 5 V voltage DC in system that is shown in this video: Which is minimal power needed to charge batteries? Thanks

Hi all, I am wondering if there is a need for impedance matching to charge a battery from the source? Thank you

Hello all, I am trying to come up with a design to have a free moving wheel create electricity using inductive charging... I am doing this project for one of the courses i am taking. I am little stumped on how i would go about designing this to create the maximum power. Do you guys have any...

I would like to charge my śmart phone and a tablet from a single charger. The specs are as follows; Charger = 5.2 v and 2.0 amps Smart phone battery = 3.7 volts and 3300 mah Tablet battery = 3.7 volts and 4000 mah So using a Y cable, will this recharge both devices with any level of...

The cell can provide conatant emf ε and initial charge of capacitor is zero. Now current through resistor initially is zero and increases. But the potential difference across the capacitor is always a constant with magnitude ε. then ##\frac{q(t)}{C}=E## So ##q(t)=CE## which implies q is constant...

I have supercapcitor 2.7V, 350F. I want to charge it by 0.001mA 20V power source. Is it safe? Thanks you!.

Hi, I'm not sure if this is a correct place to ask this, but i have a question about the charging speed for the usb chargers for phones and tablets. from what I have gathered, the device being charged is the one that pulls the current from the charger, so if a 1 amp input device is charged with...

Homework Statement Basically, I'm just trying to verify that I can do basic algebraic manipulation correctly. The objective: solve the charging equation of a simple RC circuit for (C), capacitance. Homework Equations v\left(t\right)={v}_{s}\left(1-{e}^{{-t}/{RC}}\right) The Attempt at a...

How does a person charge a particle? Like a neutron, for instance?

I know how to calculate current flow across a resister from the voltage, but what about current flow into a battery? Do I need to put a resister in the system so that I know how much current is flowing, or does that drop the voltage to the battery too much? I'm guessing the battery has an...

Two capacitors with different capacitance are charged with two different voltages. When we connect both the capacitors with the similar terminals (that is positive terminal of one capacitor to the positive terminal of the other and vice-versa) the net charge is the sum of the former individual...

Homework Statement [/B] The main problem is if it is safe to charge a solar battery as quickly as possible assuming that I have a large current charger. Let's say I have: 70Ah Solar Battery 50 F, 15 V Ultra Capacitor C = Q/V Q = CV = (50)(15) = 750 I = Q/t It = Q = 750 Ampere-second E = 15...

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown >[/color] Hey guys , I want to know about the battery defects like stipulation , erosion , sedimentation , seperator defects .

I'm not really sure where to put this question, but definitely this is just an introductory physics coursework. Let me refresh you first with the basics of the photoelectric effect. We all know that in the photoelectric effect the stopping voltage is just the kinetic energy obtained by the...

I have a capacitor bank (20x 330v 180uF capacitors in parallel). But i don't have 330v DC power supply to charge the capacitors to 330 volts. I tried using a 13.7v supply from an AC adapter, but the capacitors got charged only to 13.7v. What should i do for this?Should i use another capacitor...

Homework Statement 1. In the circuit shown below calculate how long itwill take to charge the capacitor C2 to 4 V and how long it will take then to discharge it to 1V. Homework Equations The Attempt at a Solution I tried to solve it by taking t=0 when v=0 to get the k which is then...

Hi, I have setup the circuit here: http://www.next.gr/circuits/nicd-battery-charger-l36249.html in LTspice, and am trying to understand it. If I actually build it, its purpose will be to charge 19.2 V NiCd batteries. My question is if the regulated voltage coming from the LM317 output needs...

Homework Statement I never quite understood the principles of earthing, but I think that the general idea is that if you have an object with excess charge (whether positive or negative), then connecting it to the Earth with a conductor will mean that either the excess electrons flow to the...

While rubbing the plastic rod with the wool causes the building up of charges on both of them. 1. What chemical reaction takes place between them. 2. Does it create anions and cations? 3. Is it the transfer of free electrons (I don't think so, because generally they are bad conductor of...

Please if we charge battery with high voltage like the battery charge voltage 4.2v and we supply 5v, is that will reduce the battery life. Thank you

Good afternoon. I was going to make a 4.2v Lithium ion charger circuit, but so far what i have learned is, i will be needing constant current charger, so my question is what will happen if i charge with constant voltage? Like from a regulator maybe a linear one and i give like 4/4.1 volt...

Homework Statement When it comes to charging a capacitor I'm under the impression that when a parallel plate capacitor is hooked up to a battery, that electrons simply flow from the negative terminal to the plate that is connected to the negative terminal, causing that plate to become the...

Homework Statement Why is the formula for internal resistance for a charging battery v = e + Ir? When the battery is supplying I to the circuit I understand why the terminal voltage, V, equals emf - IR (voltage lost by internal resistance), but if a battery is charging, why is the...

Mobile battery has generally 3 pins, 3rd for safety and 2 pins for supply. How can mobile devices get electricity during charging from same pins from where it is transferring power to mobile circuit? Please help

I'm using 250V 2200uF capacitor to discharge high instantaneous current into an inductor as shown in the attached image. I'm using a 12 Volt battery fed into an inverter that output 220 VAC which then is fed into a rectifier which outputs 220VDC. My question; Can I connect the 220 VDC...

Homework Statement The problem is #1 given here: http://ocw.mit.edu/courses/physics/8-311-electromagnetic-theory-spring-2004/assignments/ps1.pdf And there is a solution publicly available here...

What happens when the switch closes? Does the inductor continue to charge? If yes, how can this be so when the inductor is already fully charged (the question says the switch was open for a long time, so I assumed it has been fully charged)?

Im trying to work on a project and was curious if anyone knew if an air ionizer could be used to place a charge on objects moving through the air. If so what could be the magnitude of the charge of such an objects? The setting of the area would be probably out side but if necessary indoors.

There is this voltage source that generates different types(piezoelectric device, the pressures exerted are not the same everytime), it is not a sine wave properly(A), then passing it to a full bridge rectifier, the outcome is like B, then you use a smoothing capacitor and the outcome is like C...

I get that by getting a charged object near an uncharged one, charges of the opposite sign are induced on the surface, but, since the total charge of the whole object is still zero (because electrons move inside the conductor and can't escape because surroundings insulate it) , the object as a...

Hi there! I have a problem that I would like explaining if possible (I like to go a bit beyond the GCSE course to get a deeper understanding of the topics!). Basically if I had a charged capacitor Cx with a voltage Vo across it which is connected in series with another capacitor Cy and a...

Without moving macroscopic parts... No van de Graaff generators or piezo-something - just normal circuit that would used a battery at one point and on the other there would be macroscopicly charged electrode. :-)

I am quite puzzled about charging a capacitor. Given a resistor, in series with a capacitor and a battery, when the switch is closed 1. Why there is a current immediately The capacitor is separated by insulator, hence this is not a closed circuit. The appearance of current seems to be a...

Hi, I am currently seeking advice and looking into the idea of compound charging with two turbos. One blowing into another. Here is a basic article on the subject. Link I am currently running a single turbo setup with methanol injection on a 2.7 liter inline 6. I know the benefits of having...

MIT has a Physics Demo called "Rubber and Glass Rods with Tinsel and Balloon" (Not sure if I can post links but easily found on youtube). I have watched the video several times but am a bit puzzled. First the lab technician charges the rod by friction but then when he moves it close to the...

Hi, I want to know what is the proper methods to prolong lithium battery life: When Should I recharge the battery(at any level 90%, 70 or 40 etc)? Should I charging it fully at 100%? is true that discharging battery below 20% once each month is useful to boost battery life?

Hello guys, I have a problem charging a lead-acid battery. I have a 0-30V 0-3A power supply. If I hook up the power supply directly to the battery (with a resistor and/or diode) and set the voltage to an appropriate level, the LA battery will only draw about 150 mA. After a few minutes...

So recently, I discovered this: http://www.magicwhiteboard.co.uk/ It's a statically charged polypropylene sheet that sticks to walls, paper, etc. Apparently they retain their static for a long time. How do they charge these? A giant Van de Graaff generator? Rubbing it against a large...

Homework Statement A parallel-plate capacitor of capacitance C with circular plates is charged by a constant current I. The radius a of the plates is much larger than the distance d between them, so fringing effects are negligible. Calculate B(r), the magnitude of the magnetic field inside the...