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Questions tagged [electrolytic-capacitor]

An energy-dense polarized capacitor type, used in low-frequency filtering applications.

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Energy stored in a capacitor with dielectric

This is a problem from a book. The exact words of the problem are below: A condenser of 1 µF contains titanium oxide (\$TiO_2\$) as a dielecric with \$ε_r\$ = 100. For an applied D-C voltage of 1000 ...
Amit M's user avatar
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Why are there capacitors in series in this AC/DC converter?

In a circuit with an AC/DC converter that supplies 12V and then only 11.4V because of a diode (D16), I have found capacitors in series (C33 and C38, each 100µF 35V.) That makes no sense to me since ...
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Multiple smaller capacitors on power rail for NeoPixel / WS2812B strip

I read in the AdaFruit guide that a 500-1000uF capacitor is recommended on the power rail. However, electrolytic capacitors in this capacitance are quite large. Depending on the length of the strip, ...
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Cyclic Voltammetry for a Capacitor - Positive Current, Potential is decreasing?

In the boxed red region, why is the potential decreasing when the current is still positive? To my understanding, when the current is still positive (i.e. not changing direction), the capacitor will ...
photon's user avatar
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Decoupling capacitors for operational amplifiers

when in the refence design of an amplifier (for example OPA856) we see the + sign in a capacitor schematic, does this necessarily means we should use electrolytic capacitors? If there is no positive ...
Andromeda's user avatar
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Blowing up capacitors with a 9v battery [closed]

Hello, I have a 9V battery I would like to blow up some capacitors with; currently I have 6.3v 180uF capacitors that don't seem to blow up at least in a good time(I'm aiming for <5 seconds), they ...
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Lithium Ion Battery : Electrolytic Capacitor At Buck Converter Output

It is recommended not to parallel electrolytic capacitors with a battery due to the leakage current of the electrolytic capacitor (which is small but worthy of consideration over large time periods) ...
kando's user avatar
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Electrolytic 3-lead capacitor

I have a 3-lead capacitor that I'm having a hard time identifying. It is from an old Lafayette PF-30 receiver. I don't have schematics or a manual. It has a high squeal when turned on, and my first ...
radar's user avatar
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Possibillity of reverse polarity of Aluminum Electrolytic Capacitor

Introduction First of all, this question more like theorical rather than practical as I want to test my understanding about Aluminum Electrolytic Capacitor, which I will later called Al-Cap for short. ...
M lab's user avatar
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Power schematic questions

I received a guitar pedal in poor condition and looking to repair. Checking through the schematic, it appeared the electrolytic caps were installed backwards. All other picture I could find online ...
Glenn's user avatar
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How to identify surface mount electrolytic capacitors?

Various surface mount electrolytic capacitors seem to have no consistent marking method. Here are some examples: (Image sources: 1, 2, 3) How can I identify what value and voltage rating these are?
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Probability of explosion of a 100 µF, 25V capacitor when powered at 5V [closed]

I have a system which uses this board: Arceli Motor Control Speed. It's supposed to run for a maximum of 5 hours continuously. It has an electrolytic capacitor (black vertical tube) on which is ...
talhos137's user avatar
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1 answer
194 views

How does temperature affect ripple current parameter in electrolytic capacitors?

A maximum ripple current declared, for example, at 100 kHz and at a temperature of +105 ℃ for an electrolytic capacitor, if estimated at a temperature of +85 °C, how much does it increase? What order ...
Coriolanus's user avatar
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Can you replace ceramic or tantalum capacitors with aluminum electrolytic capacitors?

I have a question about the hookup for my 12VDC to 5VDC step down module - the K7805JT-500R3. It states in the datasheet that ceramic capacitors are what can be used but it also states that tantalum ...
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EMI filter attenuation requirement for a buck converter given EMI compliant AC-DC converter

In my application I have an off the shelf 600W 72V AC-DC converter that generates the main DC bus that powers a custom board that houses a 72V input, 9A output buck converter switching at 330kHz. A ...
Dhruv Goel's user avatar
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Calculate capacitor charging constant time connected to battery and boost converter

I know the formula to calculate the constant time for capacitor is t=RC and for full charge t=5RC. In the following example there is not resistor in the circuit but of course we are not in the ideal ...
Ahmed Mohamed Hassan's user avatar
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What is the capacitor needed for 30 kHz power rectifier?

I need to rectify 200 V at 30 kHz for a resistive load of 3-4 kW. I use a 1200 V/60 A Schottky diode bridge. I have some 6800 uF/450 V capacitors. Can I use them, or should I use other values? Is ...
Pilgrim's user avatar
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How can I measure the voltage of a capacitor using multimeter?

I'm new to electronic and trying to measure a capacitor (Aluminum Electrolytic one) using a multimeter. The cap is already charged. What I did is to touch the positive leg of the cap with the red ...
preachers's user avatar
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Mystery Voltage Across Reverse Biased Diode

I'm observing a mysterious behavior that I cannot explain. NOTE: Where I use the word "instantly" below I mean this occurs in less than the 1 ms scale I'm using on my digital scope. Also, I'...
Trashman's user avatar
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Powering RTC DS3231 through BAT pin while keeping the coin cell battery in place

I'm working on a battery-powered DSLR camera controller with a MCU (ATMEGA328P) that spends most of the time in deep sleep and a RTC (DS3231) that wakes up the MCU a few times a day to take a picture. ...
Camilo Rada's user avatar
2 votes
3 answers
573 views

Formula for calculating capacitor balance resistor values

The following formula is generally used for calculating balance resistor values used for overvoltage protection of capacitors in series when the individual capacitor voltage ratings are below the ...
Duke William's user avatar
5 votes
2 answers
805 views

Voltage drop due to leakage current in capacitors in series

When capacitors are connected in series in a DC circuit, the voltage drop across individual capacitors at and immediately after the initial charging period is inversely proportional to the individual ...
Duke William's user avatar
4 votes
2 answers
297 views

How to remove a capacitor or resistor from an electronic circuit

I would like to modify my amplifier (Peavey 6505+ 112: https://www.thetubestore.com/lib/thetubestore/schematics/Peavey/Peavey-6505PLUS-112-Schematic.pdf), by removing some components and testing some ...
Vince Skyler's user avatar
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Found some SMD capacitor leakage, can I sand them to clean the PCB?

After removing the 3 electrolytic smd capacitors from a car ECU, I found some leakage, although not sure if this is the main culprit of the problem in my ECU, but I'd like to clean them. I tried 99% ...
John Sall's user avatar
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Capacitor mounting in switched power supply

I'm repairing switched power supply. It is custom inside device and cannot be changed with another power supply. It is not first time I've had to repair it. The problem is always the same: grilled ...
Peter Novotny's user avatar
4 votes
2 answers
1k views

Footprint for Electrolytic Capacitor

I plan on using this capacitor on my project: https://datasheet.lcsc.com/lcsc/2209011730_KNSCHA-RVT330UF50V167RV085_C5155333.pdf This is an electrolytic capacitor (this means it has polarity.). The ...
user1584421's user avatar
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Calculate needed capacitance

I have this application which requires 18VDC as well as 12VDC. To get 12V I have designed a buck converter circuit which can supply up to 2A. The problem: The 18VDC (3.33A) supply may suffer from ...
bask185's user avatar
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3 votes
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Green vs black capacitor (aluminum)

I seem to have defective capacitors on a board and I am looking at buying new one to change them. The actual capacitors are green. I noticed that the green ones are more expensive than the black ones ...
Dominique's user avatar
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What is the effect of the dc link capacitor "rated ripple current" on the drain current of switching elements?

While using a capacitor with 2.3A rated ripple current as a dc link capacitor in the circuit (as shown in the picture below "Cd") I used, I replaced it with one with 2.8A rated ripple ...
Multicharger's user avatar
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3 answers
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Should I measure ripple current on a replacement capacitor of lowered ESR?

I've changed an 820 μF capacitor on the output of a 1.05 V linear regulator which feeds the PCH (Intel's Platform Controller Hub), or "southbridge", on a PC motherboard.    It's working fine ...
Deep Thought's user avatar
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Is a choke required on power supply input, 50 Hz single-phase 230 VAC

I have a 2 kW 20 kHz ultrasonic power supply which trips input power when I turn it on. I disconnected the choke between the diode bridge + and capacitor +, and connected from the bridge to the ...
Benjamin's user avatar
1 vote
1 answer
99 views

Why does this Zenith Phonograph schematic separate electrolytic and fixed capacitors

I'm currently in the process of restoring a 1960's phonograph made by Zenith. My plan is to replace all the capacitors among other things. I have the original schematic, purchased from Sam's Technical ...
Owen's user avatar
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3 votes
2 answers
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What is the current when the capacitor terminals are connected?

I need to know the current in a polarized electrolytic capacitor. What is the practical limit for this current and how do I calculate? I want to know what is the maximum current I can get when I put ...
Jádson Muniz's user avatar
8 votes
1 answer
417 views

How to estimate electrolytic capacitance from foil area

I opened a failed 1000 μF electrolytic capacitor. It contains 2 foils coiled with paper and some wet dielectric. With reasonable assumptions (to me), I can not derive marked capitance from this ...
philcolbourn's user avatar
11 votes
1 answer
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Do electrolytic capacitors lose lifetime during soldering in reflow oven?

Electrolytic capacitors service time is based on maximum operating temperature, among other things. When they are inside an SMD soldering oven, the temperature increases to over 375°C. Most of the ...
Sadat Rafi's user avatar
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Two polarized electrolytic capacitors in series VS two bipolars in parallel

I need one bipolar 4.7uF 50v electrolytic capacitor. I have polarized 10uf 50v capacitors and bipolar 2.2uF 50v capacitors. I can place two of the 10uF in series (negative leads joined) or two of ...
tomasm's user avatar
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6 votes
1 answer
258 views

Why is this circuit drawing excessive current (Suspected culprit: Large capacitor on switching DC-to-DC Converter Output)?

On a PCB of mine I'm employing two ADP2504 Switching DC-to-DC Converters (one fixed version outputting 3.5V and one adjustable version set to output 4V) which have their inputs connected to the output ...
entrée's user avatar
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Do I need to insulate the case of an electrolytic capacitor from ground? [duplicate]

I'm designing a motor controller, and I'm trying to understand if I need to add insulation between the case of the bulk input capacitors and the grounded aluminum heatsink. I know that relying on the ...
Brian Silverman's user avatar
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2 answers
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Need some help with electrolytic capacitors

I am restoring an old 1960s Sanyo reel to reel tape recorder, replacing most bad electrolytic capacitors. On the preamplifier there are ten Rubycon 6.3V 4.7uF electrolytic capacitors. I assume it is ...
Harryk's user avatar
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1 vote
1 answer
401 views

Identifying a vintage capacitor

This is inside an Allen Wales (Model 9E) adding machine. It was manufactured in the late 30s or maybe sometime in the 40s from what I've read. There are notes from a technician scratched on the inside ...
Mark M's user avatar
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1 vote
1 answer
108 views

How to visually distinguish metal film and ceramic capacitors (leaded)?

This question only involves the leaded components. Electrolytic capacitors are each to recognize since they are usually in cylindrical cans. However, I am not sure about distinguishing the other two ...
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What is the purpose of an electrolytic capacitor in this small electronics project?

As someone trying to learn electronics, I found the following diagram where there are these two electrolytic capacitors (470uF). Could someone explain the use of these components? How does the number/...
greener's user avatar
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1 answer
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Verifying my capacitor calculation

I just received in the mail a 0-60 V power supply that has the capability of outputting 24 A. I needed a high-voltage, high-current power supply to help design and test high-powered LED arrays for ...
jmoore3274's user avatar
22 votes
7 answers
6k views

Why are electrolytic capacitors still in production?

What are the advantages of using electrolytic capacitors? I know in the past electrolytic capacitors would have more capacitance, but with Multi-layer ceramic capacitors (MLCC) they seem completely ...
cats are the best's user avatar
0 votes
1 answer
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Where does the Step-Down Convertor used as compare to RECOM DC/DC converter?

I am reading Step-Down converter and given the circuit below, which is a step down converter. It consists of a MOSFET, inductor, diode, capacitor And if I compare it with RECOM component DC/DC ...
Alan's user avatar
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5 votes
1 answer
232 views

What do 'L2' or 'L3' marking codes on electrolytic capacitors mean?

I see a lot of these mysterious marking codes on very old (e.g. 1980) capacitors by different manufacturers.
Coriolanus's user avatar
2 votes
2 answers
279 views

How important is capacitor life span? [closed]

As above. I am deciding between 3 capacitors. I need 6 capacitors arranged in 2 banks with 3 capacitors in parallel each for a V+/V- unregulated power supply for an audio amplifier. Capacitor 1: ...
mrjayviper's user avatar
2 votes
3 answers
209 views

Simple rectifier circuit fails under load

I have a problem with a simple rectifier circuit that is designed to drive a DC motor. The motor is part of a ripple tank for a high school physics lab. The input to the circuit is 12 VAC from a bench ...
JamieP's user avatar
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3 votes
1 answer
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Connecting electrolytic capacitors in series to increase maximum voltage

I need to use a capacitor in a DC circuit where it would store somewhat higher voltage (hundreds of volts). The cheapest way to do that (in my case) is to connect multiple electrolytic capacitors in ...
jiwopene's user avatar
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-1 votes
1 answer
156 views

Speaker protection circuit with polarized capacitor seeing reverse voltage. Why? How?

I am looking at this speaker protection circuit found in a vintage Technics receiver. The signal from the speakers comes from the wire highlighted in green, coming from the output of a class AB power ...
MattiaM's user avatar
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