Charging Definition and 407 Threads

Homework Statement An ideal 9V battery is connected to a resistive divider consisting of a 330 Ohm and a 600Ohm resistor. A 1.5V rechargeable battery in series with a 1.5k Ohm resistor is connected in parallel with the 330 Ohm resistor. The battery has a capacity of 1200mAh and is half...

Hi All. I'm trying to get a quantitative sense of how much charge we can put on an object by rubbing: the 'triboelectric effect'. To put it specifically, suppose I have a sphere of diameter 1 cm, made of thermocol (polystyrene). How much charge, approximately, can I reasonably expect to...

I have a very basic question confusing me about charging electrochemical capacitors - When you charge a symmetrical electrochemical capacitor to 1V, because one electrode becomes positively charged and the other negatively charged, the electrode potential across one will be +0.5V, and the...

I want to charge a led-acid battery it needs 12V DC 1.i have transformer to convert 220V AC to 12V AC after that can i give 12V AC to bridge rectifier and from bridge rectifier to battery terminals directly or should i use a filter to remove the fluctuations in DC ? 2. what should be the...

I have a simple question I hope): My cordless phone handset works with two 1.2V rechargeable batteries, but the DC converter that comes with it and that is supposed to recharge the batteries has a 9V DC output ! How come ? Is it applying 9 V to recharge two 1.2V rechargeable batteries ?! Or...

Hi quick question, I have an rc circuit which is to be charged with an input voltage of 3.6 V but what happens if a pulsing current source is connected to the capacitor as well? So I have a rc circuit but also a pulsing current source connected directly to the resistor. I have attached the...

I'm trying to see if charging large capacitor banks with a limited current LDO is feasible. If the capacitors draw current past the maximum current of the LDO, will the LDO become unstable or will it be current limited?

Hi all, If I have a battery bank 12V@1000A- what size solar cell (kW) will recharge this battery bank (from flat to full) over a 8 hour period?

I was reading this question out of a book. A small metal sphere hangs by an insulating thread within a larger hollow conducting sphere. A conducting wire extends from the small sphere through, but not touching, a small hole in the hollow sphere. A charged rod is used to transfer positive charge...

A sine wave source charge a capacitor through a diode. Is it more efficiency than a DC source charging a capacitor ? base on this https://www.physicsforums.com/attachment.php?attachmentid=17653&d=1235114409

I am trying to understand how a PFN (Pulse Forming Network) could charge a capacitor to a high voltage and I have some questions first. Is there any type of voltage multiplying PFN which does not use switches or spark gaps? (The only type I have seen is the Marx type which uses either...

Homework Statement How long will it take the primary energy source to fully charge the battery pack from an uncharged state? (State your answer in hours, minutes and seconds, as appropriate.) t = 378 min. I = 100 mA Homework Equations Cb (battery capacity) = I x t The Attempt at...

hi! sir , please just tell me that this below explanation of charging by friction is right or not? If anything wrong then just give the correct explanation.I will be highly thankful if you please give your own deep explanation of this topic! If two materials with a difference in their...

Hi, Does anyone know if (in theory) it would be possible to link two iPhones together by a small cable and share power between the two? i.e if the battery is flat on one and full on the other is it possible for one of the phones to "give" power to the other? The process of how much you share...

Hello, I have an intention of making a simple igniter. I have a capacitor with large capacitance. 3300 microFarads. 35 V breakdown voltage( i think that is what that voltage means) I have plans on charging this capacitor with 24V dc source. My question here is, how can I charge this...

A capacitor is used in the electronic flash unit of a camera. A battery with a constant voltage of 3V is used to charge the capacitor to 330V at 10µA. How long does it take to charge the capacitor when C=470µF ? What is the stored energy ? What is the current delivered by the battery?

I have a few questions on DC resonant charging circuits. The circuit only has a few practical applications, most noteably Radar and there is very little info online about it. If anyone could help, I would be very thankful... 1. What would be used to calculate max current in the circuit...

Homework Statement What is the current through R2 immediately after the switch S is closed? C = 7.95x10^(-6) F , R1 = 27.5 Ohm , R2 = 10.5 Ohm , and Vo = 20.0 V Homework Equations I don't know what to use? The Attempt at a Solution I thought maybe I use two loops, the left and...

Homework Statement Make a modification so that the battery is charged by the DC supply at a current of 10mA **See attached diagram** Homework Equations The Attempt at a Solution Well I know that I would put in a resistor in parallel with the diode. However, I don't know how...

Homework Statement The figure shows three circuits, each consisting of a switch and two capacitors, initially charged as indicated (top plate positive). After the switches have been closed, in which circuit (if any) will the charge on the left-hand capacitor (a) increase, (b) decrease, and (c)...

So I was wondering if I could get some help and advice on a project I am working on. I have next to no experience or knowledge of electrical circuits so I appreciate your patience. I am trying to power a structural health monitoring system "accelerometer" unit on a bridge using...

Homework Statement I'm trying to show that not all (half) of the energy supplied by the power supply ends up in the capacitor when the capacitor is charged through a resistor. I've looked at some of the other threads on these sorts of topics and I'd thought I'd have a go at working through it...

Homework Statement Charging a capacitor - charge flows through a resistor and is accelerated between the capacitor plates Discharging a capacitor - charge loses energy by collision in the resistor. Homework Equations N/A The Attempt at a Solution Please help understand the two...

1. The problem statement and My attempt >>> Pic <<< I got wrong answer! the answer is that they just wrote the eqn's of charging a completely discharged capacitor and discharging a capacitor. i.e. CE (1 - e-t/RC) + Q e-t/RC Now does that make any sense...

I'm building a parallel-plate capacitor for a capacitance sensing circuit. If I let the capacitor fully charge, and then pulled the plates apart by 5 cm, how would that change the capacitance? Is there a formula to figure that out?

Hey everyone, so I just bought a used GE Dielektrol capacitor rated at 40,000 volts and 1.85 microfarads, and while I'm charging it up there is a popping sound that appears to be coming from inside the capacitor. It only occurs at voltages over about 2000 volts and only while the capacitor is...

Which method is more advantageous - economically as well as scientifically? Charging a battery (rechargeable) just after its use or charging it fully after its complete discharge? I read in my book that in the case of lead storage batteries, the PbSO4 produced during discharge can be easily...

http://arstechnica.com/science/news/2007/09/supercapacitor-battery-could-lead-to-instant-charging-long-charge-life.ars Ive been reading a little on this EEStor thing. With so many negative comments about it and secrecy behind it, I began pondering it and would like more feed back...

what will be the difference if the solar panel will be directly connected to the 12 volt battery or the solar panel is connected to a switching regulator before connected to the battery..which is faster to charge?..and what will be the difference in terms of power transfer?

Homework Statement An RC circuit is made of a 2.2 kOhm resistor and a 0.001 microF capacitor. The circuit is connected to a 10V source of emf for 5 x 10^-5 s. What is the resulting charge on the capacitor after that? Homework Equations Q(t) = -ECe^(-t/RC) + EC , where E is the emf...

Homework Statement A vertical piston-cylinder device initially contains 0.2m^3 of air at 20C. The mass of the piston is such that it maintains a constant pressure of 300kPa inside. Now a valve connected to the cylinder is opened, and air is allowed to escape until the volume inside the...

hello friends, Suppose my car battery current voltage is 10V and the alternator is charging my battery during the car run so if the voltage arriving at battery terminal is 13V then what value of voltage i should consider in my equivalent circuit of battery? my equivalent circuit consists of a...

Homework Statement Capacitor voltage as a function of time is recorded for a simple direct current RC series charging capacitor. How could we determine the resistance of the resistor?Homework Equations q=Qe^\frac{-t}{RC}The Attempt at a Solution I understand the question I'm just having...

I'm going to enter a "Solar-powered crane" competition where we need to design a small device that runs off a 1.5V-400 mAh solar cell. Given that 400mah isn't much in the way of current, I would like to use a capacitor to build up a little more power for the motor to run off of. My...

Hi guys, I am a newbie here and need help to start my project ! I am studying mechatronics engineering and I plan to make a wireless charging system for electric cars. I know that it uses electromagnetic field for transfering energy, but I can't get enough resources to start my project. Maybe...

Please explain to me how a parallel plate capacitor is charged and potential difference develops between it's plates when it is connected to a battery, i.e. how the negative plate is at a higher potential than the positive one. Please do not post links to some website with advanced concepts and...

Hi Gents, new guy here. I'm an ME by degree ( 25 years ago.) but it's been a while since I've done any real number crunching. ( Got moved to management.) Especially in EE areas. So here is my question. I have a couple of small 12V lead acid batteries in the 2.5-7Ahr range that I use to power...

Consider the two scenarios below: 1) charging a capacitor from 0v to 1v 2) charging a capacitor from 1v to 2v energy stored on a capacitor is 0.5*C*(voltage)^2. So the energy increase for capacitor is 0.5*C in 1) and 1.5*C = 0.5*C*(2^2-1) in 2) Assume the ohmic loss are both 0.5*C since...

I understand what a capacitor charging circuit looks like, and know how it works. My question is, with an HV boost converter charger, for charging high voltage caps, there is often an LED that lights when charging is complete. How does this work - how does the charger know when the capacitor is...

Can you tell me if I'm right with this. If you charge ten 1F capacitors in series at 10 volts. Each capacitor has a voltage of 1 volt and a charged capacitance of 0.1F. So if you discharged the ten capacitors in parallel the output would be equal to 1F of capacitance charge and 1 volt. or would...

Hello, would anybody please tell me how a charging circuit works, such as one for a capacitor in a disposable camera...how can the 1.5V battery fully charge a 330V capacitor? I believe transformers are involved to kick up the voltage, but how is DC converted to AC for that? I'd also like to know...

Hi, I have some questions please... Can I use a 9 watt solar panel to charge a 12v battery directly? Do I need a rectifier or is the loss back into the solar panel too small to worry about? Also, can I use a 24v electric motor (permanent magnet generator) to charge a 12v battery - or is...

As far as I know, they use two coils and rely on a changing electromagnetic field to transfer electric current. So would wireless charging not work for DC current since a constant voltage would create an unchanging electromagnetic field and therefore unable to induce a current in the other coil?

Hello. I am trying to find a simple method of charging a bank of 330V, 120uF photoflash capacitors that are in parallel. I would rather not make an extremely complex circuit, as all I want to do is just charge the bank in a reliable and predictable manner. I was considering using a...

Imagine you have a rod half of which is made of copper and the other half is made of polythene (insulator). If the rod is held from the insulating part (and so it's not earthed) and the copper part is rubbed vigorously with a very dry cloth, will it be charged or not? In short I want to know...

1. Why is the voltmeter is better to be connected across the ammeter and the capacitor. The whole circuit contains ammeter, capacitor and a resistor connected in series while the experinement is to plot a graph of Q against V by record the constant I, then Q=It. Homework Equations...

I'm trying to understand how I could use simple circuit analysis techniques to model a charging battery in the circuit attached. The battery connected only to a power supply will want to sink up to about 1A starting out then will transition downward quickly to about 200ma. Then it will fall off...

Homework Statement In a camera flash unit, a capacitor is charged up over a period of several seconds (from a battery). The capacitor is discharged very rapidly -- in about 1 millisecond -- into a gas tube producing a very brief, bright flash of light. How long will it take to charge a 195...

Hi, I was studying the effect of high voltage on the properties of Mylar film. The voltage input can be both DC (around several hundred volts to 1000V) and AC (same level as DC). The Mylar film is very thin, 6um, I know the film is going to be charged, but I don't know 1. how fast the film...

Homework Statement I'm confused by the interpretation of the charging and discharging formulas: Charging: Q= Qo (1-e^-t/RC) Discharging: Q=Qoe^(-t/RC) Like for Qo, like apparently its the max charge, so does that mean at the very end of charging? Initially, i thought that Qo meant that the...