Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [charge]

A fundamental physical property held by various particles, most notably electrons

0
votes
3answers
159 views

What happens to the energy stored in a short-circuited capacitor?

Suppose we have an ideal capacitor with a certain voltage between its plates. We connect the two plates using an ideal (lossless) wire, so the capacitor discharges. Where has the energy having been ...
3
votes
2answers
396 views

A question about electrons, charges and current

Let's talk about DC, a very simple circuit: a light bulb and a battery. Some authors say that electrons move from negative to positive and current from positive from negative. I always thought ...
0
votes
0answers
63 views

Samsung Powerbot Vaccum - bypass charging dock?

I have a Samsung powerbot VR9000 robot vaccum. It has 2 contacts on the bottom of the robot and docks with a 'charging station' when it is low battery. The charging dock does not charge it at all. It ...
1
vote
1answer
29 views

What determines the direction and cause of electric field exerted on test charges?

-I understand when there is an on-going electric field, if it is produced by a positive charge, the direction of electric field is away from it etc. And, if we get a +ve test charge, it repels it, and ...
0
votes
3answers
81 views

Electric field strength from AC conducting wire in form of a loop along z-axis?

Let's say I want to calculate the electric field strength from an AC conducting wire, with a certain frequency and current. The wire is in the form av a loop. I want to calculate the E-field along the ...
0
votes
3answers
113 views

Confusion over the power wires of USB (GND and +5v)

I'm converting a battery powered device to be powered off a USB connection. I think I have everything figured out except one thing. I understand there is a GND wire inside the USB cable for power, ...
1
vote
3answers
57 views

Single Cell Battery Protection ICs

I'm designing a product that will be powered by a single 18650 cell. Specifically, I am basing my numbers off this cell in particular: Samsung INR18650-25R It has a typical full voltage of 4.2V ...
5
votes
1answer
290 views

Measuring MOSFET input capacitance?

Am I calculating total input capacitance or gate capacitance or none of the above? And are my calculations even correct to begin with. The point of this is that I want to know what gate capacitance im ...
0
votes
1answer
92 views

Why does capacitor never fully discharge in this circuit?

I've found in the following circuit, when the value of RPD is very high (say 10MΩ), sometimes the capacitor actually never fully discharges and the mosfet stays partially on. The LED dims but never ...
3
votes
0answers
85 views

Parallel connection of old and new gel batteries

I have a battery system shown in the picture, 6 parallel branches of 4 batteries connected in series. The first 3 consist of old batteries which are 2 years old, the fourth branch consists of 1.5 ...
0
votes
0answers
50 views

Ultracapacitor doesn't charge

I am concerned about an ultracapacitor (2.7v, 3000F) that I received today. I set my power supply to 2.5v with a current limit of 1A, then connected a diode to the positive lead such that current ...
1
vote
2answers
40 views

Calculating charge entered into a circuit element for a given time

Looking at p 1.2-4 in Introduction to Electric Circuits by Dorf (See top of p16) I don't understand why the charge for 4 < t < 8 is 8- t. The current for that time is given as -1. So ...
0
votes
1answer
27 views

GaAs and GaN as low temperature carriers in transistor

I've been looking at HEMT to use at low temperatures. GaAs and GaN seem to be discussed often in the context of low temperature amplification. My questions are twofold. To be suitable for low ...
1
vote
2answers
38 views

Measuring floating gate potential with minimal leakage current

I am working on a sensing device where the voltage of a floating node is dependent on the quantity to be sensed, as well as the net charge stored in the node. I would like the device to be only ...
0
votes
1answer
38 views

Trying to solve a RL circuit by hand but simulator calculates a value I do not understand

I have this circuit. V3 is just a trigger to close the switch, just ignore it. The switch is open for a long time. So, the left part of the circuit is working for a long time and the inductor is ...
0
votes
3answers
170 views

Why does current have to return to its source in a circuit?

As far as I know there should be a current when a high potential point is connected to a low potential point, but apparently that is not true. I understand that a circuit must be closed in order for ...
0
votes
3answers
78 views

Average Current vs Arithmetic Average

I am just starting to learn the theory of electronics. Coming from a probability and statistics background I have a very deeply ingrained idea of the term average. The average to me is the ...
-1
votes
3answers
129 views

Voltage drop solution?

i just wanna start by saying i appreciate any help at all and am grateful for this forum! Also, the only electrical knowledge i have are that of self experimentation, no education except reading ...
0
votes
1answer
32 views

What kind of setup can take portable solar USB power & charge a AA battery charger that is usually designed to plug into a wall? [closed]

I have a portable solar panel that generates 21w of power, seen here: enter link description here . It has a USB connection wired into it that will accept a USB cord to charge small devices via USB. ...
0
votes
0answers
59 views

Batteries and PSU in parallel?

I have two 12V AGM batteries connected in series to provide 24V current. Electric load is shared by three brushed DC motors, each rated at 8A (150W). The motors are changing direction constantly and ...
0
votes
1answer
75 views

Slow-start lead-acid charge - good or bad?

I have a 300Ah battery which is near-dead (Abused in the past, around 5 years old) and want to replace it with 4-6 new 100Ah. The current method of charging is with a 30A MPPT solar controller. As ...
0
votes
2answers
109 views

Importance of the constant voltage charging of li-ion

Hello everyone is it necessary to have the constant voltage (CV) process when charging 18650 li-ion batteries? What happen if I usually skip the CV? Does the li-ion battery got memory? I know the ...
-1
votes
1answer
57 views

Input power vs charge curve (battery charging) [closed]

I want to know when charging a battery whether the charger reduces its current input as the battery reaches 80 percent charge, because it takes longer to charge the battery due to the charge curve. ...
-2
votes
1answer
53 views

How can I find charge from output signal of the Photo Mulitipier Tube?

Here I have a scintillator detector with PMT, It give a signal when a particle passing through it. I need to find the total charge from the signal. How can I find charge from the signal?
0
votes
1answer
96 views

Can throwing charged capacitors cause magnetic fields?

Since current is just buckets of charge passing through a point in space per unit time, and a capacitor is a literal bucket of charge, I had some questions in mind. Is throwing a charged capacitor ...
0
votes
1answer
64 views

Power loss in an RC circuit with very low resistance [closed]

I read at some point that an RC circuit with extremely low resistance might end up not being more efficient than one with higher resistance because the voltage change will be so fast that the ...
0
votes
2answers
126 views

Can a capacitor charge and discharge at the same time?

Is it possible to use the stored energy while the capacitor is being charged? In other words, use a capacitor almost as a conductor? My gut says the answer is probably no (and my own experiments so ...
19
votes
4answers
7k views

Do you need high voltage or current to produce a spark?

An electric spark can be formed when there is high potential energy between two conductors, right? My question is can a spark be formed with high current and low voltage or only vice-versa?
0
votes
1answer
63 views

Charging Capacitor

Is it possible to use the leakage current from many capacitors to recharge another capacitor or decrease the leakage current in another capacitor?
1
vote
1answer
640 views

MOSFET DRIVER- HIGH side vs LOW side

I am trying to understand mosfet drivers in general, no specific part. And I am encountering low side and high side drivers. My question is that if for example: I have a N channel mosfet as a high ...
1
vote
2answers
90 views

Are the anodes and cathodes in a vacuum tube truly charged?

Are the anodes and cathodes in a vacuum tube truly charged? Can I treat them like any other charged object? also how can I calculate the charge? How would I calculate the alternating charge if it's ac?...
1
vote
1answer
101 views

Why doesn't this capacitor voltage rise when the current does flow into it

I use a capacitor and a resistor to be a battery,the simulation show me the current does flow into it(charge it).The reason that i believe the current does flow into the capacitor is because that the ...
1
vote
0answers
79 views

Charging 3.7V battery from 300W+ generator

I am doing a project involving a bike generator of 500W. All of my previous projects were small LiPo battery powered devices so I want to double check certain aspects of this relatively high power ...
0
votes
3answers
2k views

Jump start car with AGM battery

I jump started a car with an AGM battery and later discovered that the 30A fuse connected to its positive terminal had blown. I suspect that this occurred while performing the jump start. How many ...
0
votes
0answers
118 views

MPPT charge control Project - LT3652

I am doing a Solar powered power bank as my dissertation project. It's based on LT3652 charge control, a Lithium-Ion battery (4500mAh) and 2 boost converters (3.3-5V and 3.3-12V). I am using a 21W, ...
0
votes
2answers
54 views

How can I increase the number of USB outputs of a powerbank which only has one output? [closed]

I'm talking about outputs which we use to charge our devices with. Would using USB male to two USB female cord be a bad idea?
0
votes
1answer
116 views

Misunderstanding from the author saying,about the current flowing path

The author show the working process of this schematic 1.The proposed system waits until the PZT device stores the energy vibrations produce during the positive half of vibration period \$T_{VIB}\$ ...
2
votes
2answers
134 views

What power supply current rating can replace 6 1.5 V C batteries?

I have a more specific question than this one. As I understand it, different 1.5 V batteries are distinguished by "capacity" (AAA < AA < C < D), measured in mAh (milliamp-hours(?), which is ...
0
votes
1answer
89 views

Not sure if this capacitor will blow up [closed]

so i have just bought a fan controller(silverstone cpf04) and it is rated with 2200μF and i am planning to connect 7 fans to it. (NF-F12)4 fans are each rated with 12v operating voltage 3.6w input ...
0
votes
0answers
37 views

battery charge terminals

This is either a nomenclature question or a sourcing question. I am working on a project that will have direct contact battery charge plates very similar to the ones on the bottom of a Roomba robot ...
1
vote
4answers
632 views

How does a capacitor resist changes in voltage?

I was reading about how capacitors work and two sentences confused me: "A capacitor’s ability to store energy as a function of voltage (potential difference between the two leads) results in a ...
-1
votes
2answers
45 views

How to know / test a supercapacitors really store the energy [duplicate]

If i charge a supercapacitor, how do i know or test this supercapacitors that it really store the energy (like a battery) and doesn't discharge ? Can anyone give some reference or method? Can i use ...
0
votes
0answers
32 views

Will this battery bank circuit work with these batteries?

I took these batteries out of an old laptop battery pack: It's a parallel array of four 3.7v lithium-ion cells (it was originally used in series in the laptop). Each one is at 4.2v. I tried to ...
-1
votes
1answer
45 views

Question of chargining the battery [closed]

When a battery has electricity,we can see it as a VDC source,but i just wonder that when we charge the battery,is it necessary to make another circuit to charge the battery or just connect it with a ...
0
votes
1answer
91 views

Capacitor charging not working according to t = rc

I have researched about capacitor charging time, with its charge being at 63% after 1 time constant, being t = RC. I am trying to repeat this by myself, using a 16V 1000µF capacitor, a 1KΩ resistor, ...
0
votes
0answers
108 views

9v Battery Recharge Circuit

I want to have a battery bank of 9v rechargeables to power my system. I want to have the recharge circuit on the PCB. My idea for the circuit is to linearly source current in reference to the ...
0
votes
2answers
252 views

How to fast charge capacitor 2200uF/400v in fewer seconds?

I have a problem to charge a capacitor 2200uF/400v. It takes 30 second to reach 300v. I hope can reach 300v in 10 seconds. thanks :) This my schematic: ![the capacitor its on output (cn2) i use ...
0
votes
1answer
34 views

The reason why the output of ZCS-controlled boost converter is 1.2V,not 1V in this paper

Here is the three stage stepping up architecture,and in the paper,the author said that when \$ V_{out} \$ increase up to 1V,shunt connecting the capacitors \$ C_{DDi} \$and \$ C_{out} ...Finally,the ...
-1
votes
1answer
106 views

How about these capacitors values?

I have a 25V 100uF capacitor and a 50V 100uF one. If I charge both up to 25 volts, then is the first one going to have 100uF of actual charge, and the second one only 50uF?
0
votes
2answers
74 views

How to isolate charge circuit from drain circuit

I am installing a 5k winch on a car hauler trailer. I will power the winch from a deep cycle battery permanently installed on the trailer. I want to keep the battery charged by connecting it to the ...