Questions tagged [electrolytic-capacitor]

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

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5answers
212 views

Why is there electrolyte soaked paper in an electrolytic capacitor?

I know that the soaked paper spacer is there to protect oxide layer but how does it protect it and from whom does it protect it? Why does the paper spacer need to be soaked in electrolyte and what ...
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1answer
48 views

Shorted capacitor

The aim of the circuit below is to continuously switch power from one LED to another (D1 & D2). The issue comes arises when I close the push switch (SW2) and an error message pops up saying that ...
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1answer
76 views

How robust and stable is this circuit?

I have a small delay circuit to automatically open my building door by pressing the intercom button for a few seconds. Whenever the intercom button is pressed the switch closes and the cap starts ...
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3answers
79 views

Are my capacitors working properly or not?

I've bought some capacitors because I needed to generate a current pulse into a coil. The idea was to charge a capacitor separately and then connect it to the coil to have a strong and brief magnetic ...
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1answer
108 views

I have a height problem (with my switching regulator on a height constrained PCB)

I was planning to use this part (datasheet) (basically MC34063 with thermal shutdown,) but I don´t have enough room above the PCB. I need to keep the components under 2.2mm. According to my ...
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1answer
71 views

How to combine elecrolytic capacitors into one big bipolar one

I want to make capacitor with large capacity which can hold both positive and negative charges. Is it possible to combine elecrolytic capacitors somehow to achieve this?
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1answer
76 views

Where to place a cooling fan supply capacitor

I want to run a ~2W, 12 VDC fan in an EMI-sensitive environment. The schematic is shown below. Due to the spiky current draw, I intend to place C1 and C2 right by the fan connector, so high frequency ...
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1answer
135 views

Circuit won't blink, and probably can't. Or can it?

I have tried to understand the simple circuits in the questions Intuitive and iterative approach to understanding of blinking LED circuit and Changing the frequency of a flashing LED. I've built them ...
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1answer
37 views

What is the Dissipation Factor of a capacitor useful for in its direct form?

Why do electrolytic capacitor makers provide the low frequency ESR in the form of a dissipation factor (DF) instead of an Ohms value as they do for higher frequency. The DF is rather unwieldy and I ...
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2answers
163 views

What are the consequences of using a capacitor that is of higher capacitance?

I'm troubleshooting a circuit board that has a dead short somewhere. I removed some capacitors which were shorted in circuit but the problem was elsewhere on the board. When testing these 1500uf 2.5V ...
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2answers
101 views

Electric capacitors instead of earthing electrode

I'm going to make a partial EM-shield (using aluminum) for my 3G USB (2.0) modem, and I need to "ground" electricity from the surface of that shield. Daily worktime for that 3G modem is ...
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1answer
59 views

Excluding visual inspection, are there general strategies for guessing at potentially damaged electrolytic capacitors in a given device?

In many cases of checking for bad electrolytic capacitors on a non-working electronic device, the number of capacitors makes it infeasible (for me anyway) to simply change out all of them one by one ...
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1answer
98 views

From where can I get the impedance graph/ frequency response information of a capacitor?

I want to know the self resonant frequency (SRF) of a tantalum or aluminum capacitor. Is this usually supposed to be there in the datasheet? I am wondering why it is not mentioned in datasheet since ...
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1answer
85 views

Can we use electrolytic capacitors on IC power rails?

Can we use bulk electrolytic capacitors on the power rails of an IC? I know that we will use bulk capacitors in switching regulators at input. Can anyone explain why or why not and how to find ripple ...
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1answer
56 views

Putting AC across polarised capacitors in headphone amp?

This circuit is from Fig. 20.3 in Douglas Self, Small Signal Audio Design, Third Edition, Routlege, 2020. This is a headphone amplifier, and as such, both input and output signals are alternating ...
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2answers
168 views

Replacing Darlington with MOSFET for capacitive discharge circuit into a solenoid?

I have the following circuit and criteria and am wondering if it makes sense to replace the Darlington transistor with a MOSFET, and if so how would that change the circuit? This circuit turns on T1 ...
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1answer
99 views

Problem simulating electrolytic capacitor at high frequency (GHz+ range)

simulate this circuit – Schematic created using CircuitLab I am simulating a circuit in LTspice in which I use an aluminum electrolytic: C=100µF, Rser=0.25, Lser=5n Due to some other components, ...
9
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1answer
172 views

What's the use case for a 0.1µF electrolytic cap? [closed]

I've noticed 100nF electrolytic capacitors are made and sold, which means people are probably buying them, but... ESR is huge, ripple current is tiny, accuracy is low, and they're larger and more ...
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7answers
269 views

How do I fix a circuit that keeps blowing a capacitor?

I have an aftermarket AC>DC wall wart that was made in China and there is an electrolytic capacitor in the circuit that blows about every 2 years and it just happened again. I'm tired of replacing ...
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4answers
93 views

Stabilize voltage on 12VDC model train loco - both directions

I am looking for a simple solution to stabilize the voltage on a 12VDC model train inside the loco, to overcome areas of bad contact on the track. For energy density I wanted to use electrolytic ...
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2answers
109 views

What capacitor value should I use for 3.3v from a buck converter IC?

I am relatively new to electronics and trying to design a buck converter circuit using the XL1509-ADJE1. The datasheet specifies that for the adjustable versions (which this is) you should use ...
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0answers
94 views

Discolored negative lead on electrolytic capacitors

Would the discoloration around the negative lead of these capacitors be a sign of failure? If so, why would the negative lead darken instead of the positive - or both leads. They are Maron EFM 35 ...
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1answer
56 views

Precise capacitor in parallel to power supply

I found this schematic in ADNS-2610 datasheet. There are two capacitors in parallel between pins 6 and 7 (GND and VDD.) One is 4.7 uF and the another is 0.1 uF, so the parallel result is 4.8 uF. Why ...
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1answer
24 views

Proper material for testing capacitor at 105°C

I've built a circuit to estimate capacitors life. I need to test it at 105°C. I have no idea which material to use for the chamber that I want to put my capacitor in and control the temperature.
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2answers
46 views

What is the effect of operating an electrolytic capacitor beyond the rated temperature?

I know that the life expectancy of an electrolytic capacitor doubles by 10 degrees decrease in ambient temperature. Is this rule applicable when working beyond the rated temperature or maximum ...
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0answers
53 views

Capacitor Lifetime

Can anyone some sample calculation on how to calculate the lifetime on an Aluminum Electrolytic capacitor who's Endurance value (Assumed as Lifetime value is 2000 hours at 105degC). The manufacturer ...
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0answers
32 views

Electrolytic caps exposed to reverse voltage... permanently damaged? [duplicate]

Accidentally a bridge rectifier was installed backwards and the capacitor bank was exposed to reverse voltage, not for too long, maybe 20-40 seconds. There were a few different brands and values of ...
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1answer
58 views

capacitor uF values question

Can I put a bunch of 220 uF caps together to get a higher uF value? or is it best to replace with the same value of cap.
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2answers
245 views

Non polarized capacitor uses

I am fascinated with capacitors. The ones I am most familiar with are the polarized capacitors. I know how they work and what to use them for. There is one capacitor though that I am not familiar with....
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3answers
3k views

Why are some capacitors bent on old boards?

I've noticed that on older boards some of the electrolytic capacitors don't sit up straight, they're not totally vertical. I wonder why this happens, is it because they were soldered by hand and the ...
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3answers
273 views

Can we use a capacitor with battery to fast charge it?

Consider this. Many capacitors connected in parallel to an input line, those capacitors are in series connected to battery. Whenever we need to charge, we plug in adapter that charges the capacitors. ...
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1answer
124 views

Reusing electrolytic capacitors?

Is reusing an electrolytic in a different circuit OK? Is the heat from desoldering liable to change the caps performance? Likewise going from lower operating voltage to higher, and vice versa?
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1answer
646 views

Why do these capacitors have an additional plastic block around them? What kind of capacitor is this?

Just saw these type of capacitors for the first time and I'm curious : Why do they have this additional block of plastic around them? Some kind of shielding? Is there some specific reason they didn't ...
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4answers
140 views

0.1 uF in parallel with larger >1 uF to reduce noise from IC

Back in the day when we would use an electrolytic capacitor across the supply of a IC we would always put a 100nf Ceramic in parallel because (if I remember correctly) electrolytics had inherent ...
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1answer
274 views

Are capacitor vents safe to touch?

I couldn't find this information anywhere. Every tutorial on how to safely handle a capacitor tells you to absolutely avoid touching the capacitors leads, and to grab a capacitor by its insulated ...
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0answers
95 views

What would be the cause of measuring AC voltage across a LM7805?

This is my first time here so I apologize if I don't provide enough information. I am trying to repair a centrifuge that is giving an error on its LCD display. Though the service manual doesn't say ...
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1answer
68 views

How to size a capacitor?

I want to design a PCB with some ICs and I've read that it's recommended to use decoupling capacitors to filter out voltage spikes. There are three ICs on the PCB: Arduino NANO, nRF24l01 module and ...
2
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0answers
39 views

Question about series-connected (pseudo-nonpolar) electrolytics

Another Q&A on this site ("Ceramic caps vs electrolytic. What are the tangible differences in use?") contains good information on capacitors in general, including parameters I wasn't ...
2
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1answer
91 views

Unexpected (unintended) capacitor charging explanation

Please first consider the below schematic. It is the balanced output part of an existing hifi preamp. Not my design, it's confidential so I can only reproduce the relevant part. Things that might be ...
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1answer
436 views

How to calculate the needed capacitance of a start capacitor for a 12V 10A DC motor?

I want to use a 12V 15A switching power supply for a 12V 10A DC motor which has about 9A start current and 6A no load current, I also want to add a push button switch for on and off function to use it ...
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3answers
190 views

Fake ELNA electrolytic smd capacitor

Few years ago I bought "pack of SMD capacitors", they came only with information about capacitance and voltage. Now I need to use one of them, but I have trouble with find information what ...
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3answers
2k views

Can an electrolytic capacitor withstand 0.1 V reverse polarity?

Let’s start the question with a brief description of my application. I am trying to attach a headphone jack with a detect pin to a RDA5807 IC based FM radio project. I am using a separate ...
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1answer
81 views

Why could my electrolytic capacitor have current but not my parallel plate capacitor?

This is for a science project. I have built my own electrolytic capacitor with aluminum foil and paper dielectric soaked in salt water solution. My parallel plate capacitor is simply aluminum foil ...
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0answers
74 views

Can I repair this motherboard damage? [closed]

I accidentally knocked a SMD electrolytic capacitor off the motherboard of an ASUS laptop I was stripping down to clean. It looks like the copper pad came off with one of the legs. So My questions are:...
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1answer
276 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
211 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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3answers
170 views

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
58 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
232 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
1k 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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