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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27 views

Battery testing depth of discharge vs cycles

I am currently investigating the relationship between the depth of discharge of a lithium battery, the number of cycles and capacity lost. I know from literature that the lower to DOD (%) the more ...
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2answers
173 views

Difference between battery and capacitor?

Can capacitor acts like power supply, in which situations? How related are charge/discharge time of battery and capacitor? Why battery has longer discharge time compared to capacitor? Why we cannot ...
6
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3answers
157 views

How do I safely discharge this capacitor with broken wire?

My electric lawn mower won't start, upon inspection some wires got loose and damaged by the motor. It's a 20µF 500V capacitor. Normally I would try to short the pins with a screwdriver, but as you ...
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1answer
44 views

Is it possible to calculate capacity of a battery using a resistor

Is it possible to measure the capacity of a battery if the discharge curve of the battery utilizes a resistor as the load? For example, if a 100 ohm resistor is connected to a battery and then the ...
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0answers
23 views

How to determine load to use in a battery discharge curve

I am making a discharge curve of a battery I am testing. So for the discharge curve, what load should I use? (This was kind of answered here, but it was kind of a guess in that the load is based on ...
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0answers
37 views

How to find the cut off and maximum voltage rating of a battery

How can I find the cut off voltage of my battery (for discharge) and a maximum voltage (for charging)? Is there an equation to do this, or are these two calculate by making a discharge curve? Thank ...
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1answer
46 views

How to make a voltage vs amp-hour discharge curve

This is in regard with another question of mine, how do you make a discharge curve with the y-axis of voltage and x-axis of amp - hour?
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1answer
48 views

How to make a discharge curve

I am trying to make a discharge curve for one of my batteries that I have. All I know about it is that it is a 1.5V battery. Now if I have to make a discharge curve for it, how would I make one and ...
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2answers
89 views

Mixing same brand batteries with similar voltage

Just about everyone has heard of the problem with mixing new and old batteries, but is it safe to mix various old batteries with each other, regarded that they are the same model and brands, and read ...
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2answers
82 views

Calculating the discharge of Ultra Capacitors

Say I have two 500F ultra capacitors, connected in parallel, charged at 15V. These are the capacitors BMOD0500 P016 B01. Then say I connect the capacitors (via an inverter) to a 230V light bulb that ...
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0answers
31 views

one-sided saturation with op-amp and RC high pass filter

I am working with a photodetecting circuit built as follow: When I drive an LED ON and OFF, I get the following waveforms: Blue indicates that the LED is turned on when a voltage is high and ...
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1answer
83 views

Why capacitors lose charge over time? How to minimize it?

Capacitors lose charge over time, even when they are disconnected. Why does it happen? Is there a way to keep the charge longer, like for years. If you cover the plates with better insulator, will ...
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3answers
76 views

Electricity needed to maintain power for camera [closed]

I am not an electrical engineer by any means and do not even know the terms I should use to ask this question but basically I am trying to determine which solar panel I can use to power my camera. ...
4
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2answers
80 views

Quasi-peak detector

This is the circuit of a quasi-peak detector: simulate this circuit – Schematic created using CircuitLab where \$ V_{\text{sig}}\$ is the input signal. When the diode is open-circuited, ...
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2answers
71 views

How does fluorescent lamp produce audible sound when blinking?

A fluorescent lamp will often blink near end of its life. Each time it blinks it likely produces a clearly audible sound which is hard to describe but it's something in between a water dip falling ...
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1answer
118 views

Are sealed lead-acid batteries safe to use indoors?

I have a small, 12V sealed lead-acid battery. I know regular lead-acid batteries can be dangerous to use or charge indoors, due to the fumes they release and the potential for acid to leak out or ...
2
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1answer
100 views

Questions on this high frequency sawtooth generator

So I found this very basic sawtooth generator: http://www.radiolocman.com/shem/schematics.html?di=143990 I have a few questions about it: I understand that when the capacitor C_T charges fully to ...
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1answer
24 views

What are possible alternatives for a depletion PMOS

I need a fast reacting way of discharging a capacitor and I figure a simple depletion PMOS is what I need. The time at which the gate has to have a voltage to keep the depletion PMOS closed is not ...
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2answers
134 views

Estimate minimum discharge voltage in a laptop battery

The objective is to determine the best 18650 cells to replace the ones in my laptop battery. To do that, I need to know the minimum voltage the battery controller accepts before ordering the OS to ...
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1answer
37 views

Capacitive ECG electrodes and capacitor discharge

I am trying to make ecg electrodes with capacitive coupling. Since my capacitor is only about 10 pF at max and I have to have as low cut-off frequncy as possible, I came up with a circuit like this. ...
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0answers
40 views

Battery Discharge Circuit

I'm looking to build a low-current (1~5mA) discharge circuit for some small LiIon batteries. I need the discharge current rate and the discharge voltage limit to be adjustable. I would also like to ...
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1answer
68 views

What is the effect of pulsed discharge on watt hour (Wh) efficiency of lead-acid batteries?

When discharging a (lead-acid) battery you see a voltage increase (volts rise) as soon as the discharge is paused. source: http://uu.diva-portal.org/smash/get/diva2:461718/FULLTEXT01 In the quest ...
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1answer
79 views

Makeshift way to drain a battery?

I have a 3.8V mobile-phone battery that I need to discharge. However I don't have any electrical components (say led) with me. What is a crude way to do this using household items?
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2answers
69 views

capacitor discharge direction

This is probably a dumb question, but I am sort of confused. What direction does a cap discharge when a system is turned off? For example, decoupling caps that go to ground. When I shut a system down, ...
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0answers
36 views

CRT grounding question

I am going to convert a CRT monitor into a high voltage power supply. I have been watching some people do it. The problem is, you must unplug the CRT before working on it. So how will connecting the ...
2
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2answers
429 views

A few questions about basic capacitor concepts

So say you a typical setup like in this diagram. How does current flow while the capacitors charge? To elaborate, what is the mechanic that makes capacitors mimic the functionality of a wire ...
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1answer
55 views

Maintaining DC voltage with more batteries

I have a circuit which i am powering with two 1.5V AA batteries that dies at 2.6V volt as the battery discharges. Reading around, i realized that even though there is energy in the batteries, my ...
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0answers
25 views

I wanna set a voltage from which a capacitor charges and discharges back to. How?

Ok, so I am using the capacitor characteristic exponential charge and discharge to drive a simple circuit that lights the LED gradually which in turn drives the LDR. Since this circuit is controlling ...
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1answer
65 views

Reviving an overdischarged NiCd 12v battery

Some time ago I recovered a 12v 1700mAH Ni-CD battery from an ancient Commodore Amiga black and white display laptop. The laptop works perfectly when powered by a 1.5a 12v adapter, but unfortunately ...
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1answer
94 views

Ratio Between Voltage and Charge

Is there a ratio between the voltage and charge of a battery? I mean, the voltage falls slowly while the charge is consumed? Or occurs a sudden drop of voltage when the charge is at the end?
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1answer
64 views

Use a steel welding table to ground yourself from electrostatic discharge (ESD)?

I have a large steel welding table that I have been using as a work station to solder together my own custom PCBs. I have been using my anti-electrostatic discharge grounding bracelet and connecting ...
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1answer
42 views

discharge of capacitor through a current source

Assume we have a cap connected to a current source that draws a current \$I_0\$. What time would it take to discharge the cap by a voltage \$V_t\$? $$t=\frac{C \times V_t}{I_0}$$ Is this correct ...
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1answer
50 views

How to maintain equal discharging on batteries

I am currently building a robot that has one 12V battery for each drive motor. The system was originally setup so that the two motor/motorcontroller/battery systems were completely separate. After ...
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1answer
386 views

Why does a IRFZ44N turn fully on on my battery discharger while a IRFZ46N doesn't?

I've made a simple MCU controlled NiMH AA battery tester a while ago and it works just fine. The schematic below is its discharge circuit for one NiMH AA cell. Q3 is a IRFZ44N MOSFET. Signals ...
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2answers
123 views

Are BLE modules capable of working with a CR2032 battery? [duplicate]

I keep reading that the Bluetooth Low Energy modules are capable of working with a CR2032 battery for years, but their consumption is around 20mA and the max discharge of a CR2032 is around 3mA (200uA ...
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1answer
138 views

Battery Discharge

I am making a circuit to discharge an 18V Li-ion battery, with multiple cells, in order to condition it. Each 18V cell has a capacity of 100Wh when fully charged. I would like to control the condition ...
4
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2answers
307 views

How deep should we discharge lithium batteries to maximise their lifetime?

Recently I posted an answer mentioning the very classic "lithium batteries like partial discharges, so design your system for limited depth of discharge". But then I wondered: with partial discharges, ...
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1answer
387 views

Arduino and N mosfet lithium battery charging/discharging measuring capacity

I need an Arduino based lithium battery tester that uses N channel Mosfets to switch On charging from and external power source and discharging through a 2 Ohm resistor. I have no issues with either ...
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1answer
128 views

Max discharge rate of Alkaline AA batteries?

I'm in a bit of a tight situation, as I need a new battery pack for an upcoming competition, so I've tried to make my own. I put 7 of these: ...
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1answer
79 views

Natural discharging duration of an unpluged capacitor

Can natural discharging period of a charged capacitor be detected by a certain formula? If it is related to initial voltage and the internal parasite resistance, what are the factors affecting this ...
0
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1answer
107 views

Capacitor and discharger selection for pulse discharging

I want a 100 Joule pulse in 350 micro seconds. I have 1000V nbu 1012 capacitor discharge circuit . In datasheet, Max. average power is 3000 W(page 8), however I need 100/350us= 285kW instantaneous ...
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2answers
318 views

How to properly discharge a high voltage capacitor?

I have recently blown a capacitor on my home made emp. I have got the perfect replacement which is an electrolytic capacitor, 330v, 140 micro farads. I have charged it but I want to learn how to ...
0
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2answers
100 views

About battery capacity and regulation

For a portable application, I would be using a single 3.7V 2600mAh li-ion cell. The circuit requires 2.5V to 5V to function with the current requirement being 100mA. So obviously a voltage regulator ...
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1answer
194 views

Modeling Capacitive Discharge Ignition (CDI) Circuit

I am trying to model a capacitive discharge circuit (see Fig. 1 below), but I'm having difficulty properly coupling the two inductors on the transformer and also estimating the energy dissipated ...
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2answers
135 views

Capacitors not keeping charge as expected

I have a voltage doubler charge pump that is used to provide voltage over an IR LED for a short pulse, I also have a driver circuit for the LED to sink the right amount of current that I am requiring. ...
3
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1answer
93 views

What external factor could cause increased current draw?

I have a metal cased device powered by 2x 1.5v AA batteries with a standby current draw of 19.7 microAmps. If I then cause a build up of static by shuffling across a synthetic floor and touch the ...
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1answer
74 views

Effects of C Rating on Battery Life

A polymer lithium ion battery is rated at 3.7v, 6600mAh and a maximum discharge current is specified at 3.3A. I take it this means the battery can be discharged at 3.3A and last for two hours since ...
3
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2answers
87 views

How can I use the presence or non-presence of an 120VAC input to actively discharge a bias power rail?

I'm designing a power supply that has an input of 100VAC to 300VAC. On the primary side on the main transformer, I have a 15V rail to power the control chip (a FAN6920) and a gate drive chip (a ...
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1answer
169 views

How will unmatched lithium-ion cells in parallel react?

We are stocking a portable power pack for USB charging. We tested them when they first arrived and found no issues but after 3 months we tested some of the remaining stock and found about 50% of them ...
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0answers
97 views

Li-SoCl2 battery state of charge

I'm developing a data logger powered by Li-SoCl2 (http://www.100y.com.tw/pdf_file/02-SAFT-LS33600.pdf) battery and I have no idea on how to overcome the problem of estimating the residual charge of ...