The process of removing energy from a store, such as a capacitor or battery. Stores may be parasitic, resulting in rapid spontaneous accidental discharge, as in a static shock.

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How to calculate time for NiMH batteries to discharge?

I want to use 4 battery cells AA NiMH (or NiCd) 1.2 V, 2600 mAh in order to power up circuit that requires 5 V, 300 mA. I know that fully charged NiMH can provide 1.35 V each, which means 5.4 V in ...
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3answers
150 views

Why charging time is same and discharge time is different for two inputs in dual slope integrating ADC?

For different input voltages in dual slope ADC, charging time remains same but discharge is proportional to the magnitude of the input voltage. How it works in that way ? Charging time is independent ...
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0answers
36 views

Discharge limit on a 12V 9800mAh Lithium-ion Battery

I am running a 12V solar system that powers a 5050 LED light bar of 7.4W. Powered by a 25W mono PV and has a total 12V storage of: 1x 6800mAh 1x 9800mAh (Lithium-ion batteries in series) The ...
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2answers
52 views

Grounding a conducting object

Is it possible to trap some electricity in the object even though the object is grounded? For example if we ground a conducting sphere over a resistor, will all electricity leave the sphere once it's ...
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1answer
113 views

Capacitor discharge math discrepancy

I'm trying to cross check mathematically the mA being discharged from a .33uF capacitor which is charged to about 1200V by a circuit which is provided 37W of power to it. I do it three ways. 1) ...
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1answer
101 views

Safely discharging large value capacitor without blowing it up

This is related to my previous question. I have this circuit in which I discharge the capacitor by turning ON M2. The ON resistance of the MOSFET I have in mind (the picture shows the wrong MOSFET in ...
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1answer
179 views

Discharge curve of a LiPo battery

What is the mathematical formula to calculate the voltage of a (typical) LiPo battery as a function of it's charge, current flowing and external temperature?
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1answer
151 views

How to measure battery charge and depletion over time

When using my various electronic devices, they always seem to know how much charge is left in the battery. They also know when the battery is completely charged. Not exactly sure how this is ...
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1answer
96 views

Preventing Arc Discharge

I am repairing some ozone generators and one of them has a tower with a discharge path I can't seem to get rid of. Back in the heyday of television, my dad ran a side (hobby) business repairing bw ...
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1answer
118 views

Static electricity discharge, what gets transfered?

Ive been studying Maxwell equations at school and I solved several excercises regarding electrostatic fields, however I still have some very basic unanswered questions: When a non conductive object ...
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1answer
362 views

How to Calculate the charge/discharge power of a battery?

I need to measure the discharge power of a battery in general. At the end i want the maximum charge/discharge power as a function of the state of charge(SOC). So i need a curve that looks like the ...
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1answer
138 views

Can leaving rechargeable batteries in the unplugged charger for a few weeks cause batteries to lose their charge?

Is it okay to leave rechargeable batteries in charger even if it's not plugged in?
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1answer
283 views

How to detect low battery of a lead-acid battery?

I've heard that discharging a lead-acid battery to 0% is bad and wears it out. I have a 10Ah 12v lead-acid battery, is there a circuit to tell me when the battery is low?
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2answers
863 views

How do I determine the maximum amp output of a battery pack?

How can I determine the maximum amp output of a battery pack? Some background: I've got a 5-AA battery pack hooked up to a microcontroller and some continuous rotation servos, but there's current ...
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4answers
389 views

Sawtooth generator not working - transistor wont discharge my capacitor

I have been trying to build a sawtooth generator using current source which linearly charges my capacitor and a comparator which was supposed to discharge my capacitor, instead it doesn't. Here is the ...
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4answers
3k views

Circuit to safely power-down Raspberry Pi

I want to use a Raspberry Pi as an XBMC server in the car. The XBMC docs say that you should always use the shutdown command before disconnecting the power. I don't want to have to (tell my wife to) ...
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1answer
179 views

LiPo discharge circuit doesn't work

A friend of mine gave me this circuit to discharge a 3V7, 5000mAh single-cell LiPoly accu: simulate this circuit – Schematic created using CircuitLab The zener is to make sure that the ...
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1answer
607 views

Constant current battery discharge

I'm simulating NiMH cell discharge from 1.5V to 1.0V. The circuit I drew is supposed to draw a constant current from the battery. I simulate a DC Sweep in circuit lab but somehow the current draw ...
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1answer
262 views

Why is this capacitor not discharging?

I am trying to implement a delay mechanism out of passive components. The digital input in this case is a PIC input pin. The operation is as follows. The capacitor is pre-charged to 5v, and then the ...
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2answers
148 views

Need help designing a custom box

I am doing a hobby project and I don't know much about engineering; therefore I decided to ask pros. I have a 12v electric device that runs on Car battery only and I need to make it work if there is ...
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1answer
143 views

LSD NiMH cells that provide reasonable capacity even in subfreezing temperatures

Sanyo claims that 2000 mAh Eneloop LSD AA NiMH batteries provide about 1400 mAh at -10 °C (-15 °F). I wonder if only Eneloops provide reasonable capacity in the cold, or if the competition does too. ...
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1answer
1k views

Calculating resistance given capacitance and charge over time

Given the seconds \$t\$ it takes a capacitor (with farads \$C\$) to discharge from 5 volts (\$V_0\$) to 0 volts (\$V_t\$), how do you calculate the effective ohms of resistance R in a circuit? Based ...
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3answers
639 views

Automatically discharging capacitor [closed]

Say I have a capacitor of 100uF connected to 2Volts battery supply (In real circuit, this will be a solar panel exposed in the sun)... After some time, the capacitor will be charged fully with a ...
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1answer
268 views

Capacitor discharge after charge

I have this circuit for charging a capacitor: What I need is a circuit for discharging the capacitor after 'V' (the voltage across the 100 µF capacitor) has reached the maximum value of 2V. I ...
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1answer
563 views

What's a good estimate on how low an alkaline battery voltage can be to still make the battery useful?

Here's a YT video by Duracell about how many batteries declared dead and sent to recycling still have some usable energy. In the beginning of the video there's a sequence where they have a row of ...
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2answers
1k views

Making a lithium polymer circuit

I want to create a circuit that will power my Raspberry Pi using Lithium Polymer. My knowledge of LiPo is rather low and I believe they can get dangerous if used incorrectly so I turn here. THe ...
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1answer
492 views

Constant power discharge of a non-ideal capacitor

My employer sells boost converters to hold up motor drives during power loss. These boost converters are fed from capacitor banks. In order to size these banks correctly, we need to take their ...
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1answer
3k views

What's the max discharge (in “C”) of a Pb-acid and LiFePO4 (lithium iron phosphate)?

I know that lead acid batteries can handle massive loads, and they are even used to power houses with solar panels, but what is the maximum safe discharge for one of these? I've done some Googling ...
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3answers
6k views

At what voltage is a NiMH battery empty?

I have a battery pack of NiMH batteries. It is ten cells with 1.2V, 4000mAh each, put together in series. So rated voltage is 12V. After charging, i.e. when the charging device says that it is ...
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6answers
612 views

Understanding voltage and current

While reading "Electronics for dummies" went through the following block and I realised that I have some uncleared concepts about electricity: Electrostatic discharge involves very high voltages ...
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3answers
14k views

How can I quickly and safely discharge a charged capacitor (small and low voltage; <= 42V)?

I am learning how to use capacitors (ceramic and electrolytic from 1pf - 1000uf) and am trying out various experiments using a breadboard. I am constantly adding/removing things to my layout to see ...
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2answers
2k views

Adding voltage cutoff to a circuit? 3s li-po [duplicate]

Possible Duplicate: Adding voltage cutoff to a circuit? Adding voltage cutoff to a circuit? I'm powering a project with a 3-cell 11.1V LiPo battery. What circuit do I add to make the unit ...
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3answers
14k views

How to Calculate the time of Charging and Discharging of battery?

How do I calculate the approximated time for the Charging and Discharging of the battery? Is there any equation available for the purpose? If yes, then please provide me.
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2answers
319 views

Properly charging and discharging Lithium cells during battery testing?

I'm working on some software that automates charging and discharging battery cells to generate discharge curves. I have a few concerns about properly charging and discharging of lithium-ion / ...
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2answers
3k views

Capacitor Discharge through Constant Current Source

I was just thnking of how to model the voltage decay from a fully charged capacitor through a constant current source (CCS). A good approximation to this would be to model the constant current source ...
2
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1answer
323 views

charging and discharging capacitors

I'm wondering if it's possible to charge say a capacitor with a stepper motor (~12V DC after rectifying), which when it reaches its maximum capacity discharges. I'd like the discharged power to ...
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2answers
744 views

Way to discharge solenoid without (heated) resistors?

Here is a simple simulation of a schematic for my solenoid: Once the switch is closed, the solenoid will be activated with ~80mA charge. When it is open (where the screenshot is at) it will ...
3
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2answers
3k views

Can I Test Bug Zapper's Voltage With Multimeter?

I have The Executioner bug zapper: Although it uses 2 AA 1.5v batteries, it also has voltage multiplier like Cockcroft–Walton generator i guess and would like to know if it is safe and would make ...
7
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5answers
5k views

How does corona ring help against corona discharge?

Corona discharge is flow of current from the electrode to the outer air. Corona discharge happens (among other) in high-voltage power lines. One way to reduce corona discharge in this case is using ...
5
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4answers
7k views

How do I find the maximum “discharge C rating” of a battery?

I've been experimenting running my 3A LED strips off battery power and the results are disappointing. I'm only getting a few minutes (< 10) out of a YSD-168 1800mAh lithium ion. How can I find the ...
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6answers
6k views

Is it possible to fire a spark plug from batteries

I wanted to create a remote fired trigger for a spud gun so I can trigger it remotely. Ideally I'd like to use a spark plug to fire because it should work well for gas mixtures but the trigger is ...
11
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4answers
13k views

How do I calculate how fast a capacitor will discharge?

Say I have a 1F capacitor that is charged up to 5V. Then say I connect the cap to a circuit that draws 10 mA of current when operating between 3 and 5 V. What equation would I use to calculate the ...
7
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5answers
1k views

RC circuit understandings

I am trying to understand the principles of a RC charging / discharging circuit however I'm at loss regarding certain aspects of its operation. I have a square wave generator giving 0v to 5V levels ...
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3answers
176 views

How to I determine/ interpret values of autoranging multimter

I have an autoranging multimeter and many AA batteries.... how do I interpret the readings when deciding to keep or discard AA (1.5 volt) batteries?