Questions tagged [electrolytic-capacitor]

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

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1answer
70 views

Are aluminum electrolytic capacitors suitable for encapsulation/potting?

Because aluminum electrolytic capacitors generally incorporate a venting mechanism for over-temperature/over-pressure events, are they suitable for complete encapsulation in potting compound? ...
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2answers
128 views

Can my circuit be submersed in oil?

I've been asked if a design of mine can be immersed in transformer oil. (And still function properly!) The circuitry is mostly SMT Qs, ICs, Rs, ceramic Cs all of which I think are OK but I'm unsure ...
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Switched power supply capacitors

Lots of electronic hardware gets problems its psu and more specificly: with the electrolytic capacitors. How do old capacitors usually affect the capacitance of that electrolytic capacitor? What ...
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1answer
53 views

Decoupling capacitors - placement close to DC output

I have a general question regarding the placing of decoupling capacitors. Example at DC Vout of SMPS or LDO regulators. Does it really matter which capacitor out of 100nF, 1nF and 10uF is placed ...
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3answers
101 views

Replacing the capacitor on an old Philips amplifier

My Philips amplifier broke down (model FA153) and my friend told me it's likely the capicators have worn out (they were produced in West Germany ;)) I am quite the layman in electrical engineering, ...
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4answers
81 views

Orientation of an electrolytic capacitor in a circuit

I am attempting to debug the following circuit. Looking at the schematic, starting at Vin on the left of the diagram, I want to figure out if the 10uF capacitor is the issue with the circuit. This ...
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1answer
26 views

Use two 250V series cap in APFC instead of single 400V

I have a EVGA 500W PSU with an APFC which is causing spike noises, presumably from the APFC or main switching as they both run in sync controlled by the CM68000TX combo apfc switching PWM chip Noise (...
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1answer
41 views

Substituting a capacitor of different capacitance [duplicate]

If a circuit calls for a capacitor with a specific capacitance, what happens if a capacitor with a different capacitance is substituted? I have a circuit that calls for a 250uF capacitor to power a ...
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0answers
20 views

Ac current injecton to dc bus

I want to inject a 2V ac sine wave on a 480V dc bus. to protect my ac signal generator from entering high dc voltage I am going to use capacitor as coupling device. Ac generator also should deliver 15 ...
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1answer
34 views

Using SPST Switch as Button using Capacitor, which type?

Before I start, know that I'm still very much a beginner at electrical engineering. I'm building a switch box to be used for PC simulators using mainly (non-momentary) SPST switches and a USB encoder. ...
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0answers
37 views

How to Determine Input Capacitor Value for Peak Power Requirement

For flyback SMPS, how do we know that our input capacitor value is sufficient for some peak power requirement? I understand that bigger input capacitor will have more advantage on this peak power. ...
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1answer
48 views

Finding out capacitor polarity on pcb

I made the quintessential newbie mistake: I removed 2 capacitors (CF07/CF08) without noting down the original lead position. The interesting part is that the schematic (attached) seems to convey that ...
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1answer
104 views

24 AC to 32 DC. How?

I encountered the following problem: inside an equipment, an added PCB needs 32 V DC and in that enclosure, only 24 V AC is accessible. In order to get 32 V DC from that 24 V AC, someone put a bride ...
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1answer
63 views

Tiny 0.33 F Capacitor

I need to replace these (what I think are) capacitors, but the rating seems very high. They are smaller than the tip of my finger, yet the label pretty clearly says 0.33F, 5.5V. This seems wrong, as ...
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1answer
67 views

Can I change 1000 uF, 16 V for 1000 uF, 10 V?

Few days ago my main monitor did not turned on. I opened it and discovered three capacitors, of 1000 uF/16 V each, in bad shape. Since all stores here in my town are closed due the quarentine, I'm ...
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1answer
47 views

Remove electrolytic capacitors for a class-D amplifier

I'm referring to this schematic TPA3251 Evaluation Module, pg. 18 Question: Our current board design has an SMPS (flyback, 36V, ripple 50mV) & amplifier (TPA3251) in the same PCB (4 layer.) Due ...
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1answer
73 views

How to test if a capacitor is good if my DMM farad's range is less than the capacitor's

So I found out that my DMM maximum reading is 100uF (Though its price is twice the ones that reads upto 100mF, mostly because its 8 years old). It doesn't have manual range for capacitance measurement,...
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1answer
41 views

How to find out the values of a surface capacitor

Surface resistor has numbers on it to decide whether it's good or bad after measuring it with DMM. But when I looked at surface capacitors, they don't have numbers or strips to decide their validity ...
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2answers
60 views

How long do electrolytic capacitors last in seldom-used equipment?

I have a Fender solid-state amplifier nearing its 40th birthday. I've been going through it, replacing some failed logic chips and updating some of the op-amps (gaining about 10dB in S/N ratio!). ...
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3answers
27 views

When to not use electrolytic caps at the input of flyback converter?

This reference design does not use bulk capacitors at the rectifier output. It uses small ceramic capacitors. On the bright side, I like it because it eliminates the reliability issues of electrolytic ...
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2answers
100 views

Replacing these capacitors?

This is a controller board for a home ventilation system. It runs fine most of the time but sometimes the ventilation stops for one minute, then starts again and runs normally for anywhere between one ...
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0answers
30 views

Techniques for measuring the ripple current of SMD electrolytic capacitors

I am currently creating a test plan for an AC/DC converter (90VAC...264VAC -> 12VDC) I've been working on. Since the output electrolytic capacitors are of SMD type, I am trying to come up with ...
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2answers
87 views

22uF 0805 SMD capacitor for voltage regulator?

I'm trying to use some part of this circuit dual power supply circuit: http://embedded-lab.com/blog/multi-purpose-dual-power-supply-5-0v-and-3-3v-regulator-board/ Credits to embedded-lab.com. I ...
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1answer
24 views

Interpolation of electrolytic capacitor's dissipation factor / loss angle

It is a common practice for capacitor manufactures to define either the ESR or the dissipation factor (aka loss angle) at a given frequency (e.g. 120Hz, 1kHz or 1MHz). It is also clear that their ...
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2answers
180 views

Real world brushed DC motor bulk capacitance calculations

There's a lot of great information on driving DC brushed motors from h-bridges. Preventing back-emf with diodes and bulk capacitance from electrolytic capacitors When designing a high powered h ...
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2answers
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Why do some SMD electrolytic capacitors have platforms?

I’m working on a computer monitor’s power board (to replace a capacitor or two, which I assume is the problem), and found these: Replacements are easy to find, so no issues there, but I’m curious why ...
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Electrolytic capacitor polarity voltages

What happens if we feed an electrolytic capacitor only positive voltages while keeping the negative pin voltage lower than positive. for example positive pin 20V and negative pin 5V. Does it affect ...
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1answer
1k views

Desoldering a through hole capacitor with weird terminals

Apologies in advance if this is the wrong place to post this question. So I've just RGB modded an old CRT TV, and now I'm trying to replace a series of capacitors to hopefully fix some screen ...
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1answer
81 views

Can failure of an old electrolytic capacitor be precipitated by motion?

I have report of a circuit board failure. The board was 20+ years old, and included at least one electrolytic capacitor. That capacitor would then be beyond its expected useful life. The board was ...
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5answers
3k views

High short circuit failure rate of aluminum electrolytic capacitors during the production processes

I have produced 1000 units of our new developed energy meter. Almost 20 aluminum electrolytic capacitors (2%) have failed short when we test them during the production processes. The Capacitor is a ...
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3answers
205 views

Charging 2 super capacitors in series

I have recently received my order of 2 2.7V 500F super capacitors from eBay. After much searching, my yet unanswered question is: Can I connect both of these capacitors in series and charge with 5V ...
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1answer
86 views

Coilgun capacitor reverse voltage in my schematic?

I'm going to build a coilgun and have thought about all possible problems, which I solved except the reverse voltage problem. I designed a schematic based on some other schematics I found online. My ...
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1answer
93 views

Can a smd aluminum electrolytic capacitor be replaced with a normal electrolytic cap?

I have a JBL Charge 2+ amplifier that during dissasembly I missed a major step and accidentally broke off about 2 to 4 of the SMD electrolytic caps. Instead of buying replacement ones I already have ...
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1answer
325 views

What is the use of a capacitor in a DC motor circuit?

I'm trying to understand all the components I need in order to drive a DC motor through an Arduino. I saw this circuit below, which has a capacitor (other sources show same circuit but without the ...
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3answers
1k views

Why should care be taken while closing a capacitive circuit?

The other day in class, our professor told us that care should be taken while closing a capacitive circuit and while opening an inductive circuit. Why is this so? I partly understand the inductive ...
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2answers
145 views

Why use both big polarized cap and small non-polarized cap in the TB6612FNG DC motor controller terminal?

In the datasheet of TB6612FNG DC motor controller, Typical Application Diagram section. Both DC sources are smoothed by caps. But I don't understand why there are two caps in each position. The ...
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1answer
101 views

My RT8272 buck dc converter fried in my test charging circuit for arduino

I'm building a circuit to power an arduino and later a stepper motor from a 3A 24V DC source. The DC power source is a switching power supply, much like those used in notebooks. I'll need after ...
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1answer
82 views

Can a castellated PCB/module have electrolytic capacitors in it?

We're designing a small module (3in x 3in) that will have castellations on the edges for connection. I just watched a video on castellation PCB design. The video talked about the module going thru ...
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0answers
47 views

How to calculate a capacitor's discharge time? [duplicate]

How do i calculate a capacitor with a specific capacitance loaded with a specific resistance discharge time and reach a specific voltage? So let's say i have a 22uF capacitor charged with 12 volts ...
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2answers
67 views

Discharging radial electrolytic capacitors

I'm a beginner/intermediate in electric engineering and had to discharge a few electrolytic capacitors last week in a hobby starter kit (not too high voltage) and now I have to discharge some more ...
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1answer
631 views

Why do some devices use electrolytic capacitors instead of ceramics for small value components?

I've recently run into a number of consumer-grade devices that use 50v, 0.22uF electrolytic capacitors, as well as other similarly rated parts, all below about 10uF. In use, the voltages on them are ...
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1answer
80 views

Safe way to reform high-voltage capacitor

This week I received an old photographic studio flash unit made in the early 1960'ies. Inside is a huge 40µF/2500V capacitor. I don't know the usage history of the unit; it may not have been used for ...
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0answers
32 views

Aluminum Electrolytic Capacitor submersed in synthetic (PAO) oil

We are testing solar water pumps which have the 3phase inverter for the BLDC in the down hole pump. The boards (one power board, one controller board) are submersed in the lubricant oil that is used ...
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1answer
85 views

Assembling and Dis-assembling a Charged Capacitor

If I have an electrolytic capacitor, which is a cylindrical body in which the two plates are rolled-up with a dielectric paper in between them, of very high value (say 1F) and I charge it using a DC ...
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1answer
67 views

Brand / Supplier of this capacitor

Having trouble to identify this capacitor, not for its values but its specifics. They're all being used in the AKAI reference series. This particular photo was taken from the power supply board of the ...
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3answers
5k views

Is the capacitor drawn or wired wrongly?

In my recent study of electronics, I chance upon a guide on building a line-following robot. In one of the diagram shown, I realized that the capacitors, namely, C1, C2, C4 and C5, all marked with red ...
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1answer
88 views

Two modes of electrostatic force with charged capacitors?

During a charged state of a capacitor (Regardless of the type of capacitor), Simple parallel plate: .png Parallel plate with dielectric material in the gap: ]3 Supercapacitor: How is the ...
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2answers
895 views

Bulk Capacitor for Motor Driver

I'm creating a motor driver for a BLDC motor. I was wondering how we can calculate or choose what capacitance we need for our purposes. We're using the motor driver for a chain drive /transmission ...
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1answer
567 views

Can you identify these SMD Electrolytic capacitors? [closed]

I'm fairly sure I need to replace the capacitors in this LCD panel from 1993, but I'm not 100% sure I'm reading them correctly. I'm guessing that the large ones are 47uF 16V, the medium ones are 10uF ...
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2answers
188 views

Decoupling capacitor placements and ratings - how to choose?

I am building a circuit with 2 hybrid stepper motors each powered by a stepper motor driver A4988 and both drivers are connected to an Arduino UNO R3. Before soldering the components together on a ...

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