A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.

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Film capacitors, replacing with ceramics

I've been watching through hole film caps disappear. I've used a bunch of these in thermal control loops, http://www.digikey.com/product-detail/en/ECQ-E1106KF/EF1106-ND/56416 Still making 'em, but ...
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3answers
64 views

Parasitic Capacitance and AC Coupling

I was reading on Capacitive Coupling a bit and become confused when reading the Parasistic section, specifically regarding two claims. If a high-gain amplifier's output capacitively couples to ...
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1answer
79 views

Difference between capacitors of same value but different sizes

I would like to know why some capacitors have the same value (capacitance) but their sizes are different? What is different between those capacitors?
9
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1answer
2k views

I stuck a 450 V 10 µF capacitor in a 110 AC wall outlet and it exploded… why?

When I put it in the outlet it "popped" with some oily gray smoke. Honestly I thought that the voltage rating on the capacitor meant you could feed at least that much voltage through it, but clearly ...
2
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0answers
103 views

What purpose does the capacitor serve in this schematic?

I'm looking at this schematic someone did for daisy chaining a set of 74HC595's and I wanted to know why there is a capacitor put on the pin4/latch and the GND. What purpose does it serve and why is ...
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1answer
127 views

Resistor in series and capacitor in parallel to ground

Could somebody tell me why someone would need circuit like that in supply rails? I assume it is for making DC voltage smoother by parallel capacitor. However, my 24V power supply has 500mA output ...
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3answers
123 views

Solid state circuit to charge caps in parallel then discharge in series?

Do there exist a solid state design circuit to do the following: Charge multiple capacitors in parallel for a certain amount of time from a low voltage DC source, then disconnect them completely from ...
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1answer
27 views

Rated capacitor current

What does "rated current" refers to in the capacitor data sheet? Is the current that the capacitor can supply? I always assumed that it is the current that the capacitor can source. Is that correct? ...
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1answer
79 views

How to calculate the values of capacitors for 5V DC power supply

I am trying to make a power supply of 5 V; as we all know it uses a bridge circuit, then capacitors and LM7805. But I want to know how the value of capacitance is calculated. What is the formula for ...
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2answers
35 views

Why would an 8-order LPF switched capacitor has a least steep roll-off curve (max7405)?

As far for my understanding, a higher order LPF will have a steeper roll-off curve. Something like below would happen if we increase the number of order for the LPF: Normal LPF frequency response ...
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1answer
28 views

How to calculate the oscillator capacitor value for a switched capacitor (MAX7405)?

I would like to use an 8-order LPF switched capacitor: MAX7405 datasheet The cut-off frequency can be set by simply connecting an external oscillator capacitor, Cosc. I would like to design a 50Hz ...
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48 views

Capacitor with parallel & series Resistors charged with Constant Current source [closed]

Given the circuit shown in the attached picture, of a constant current source (i) with a series switch to a load consisting of a resistor (P) in parallel to a capacitor (C) and resistor (S) in series. ...
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223 views

What is the role of the capacitor within the assembly

I have some questions regarding my assembly and especially on the role of the capacitor within the circuit. Before I added the capacitor I encountered 2 issues: when the piezo was squeezed (a ...
0
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1answer
86 views

Minimum number of capacitors

I require a capacitance of 2×10^-6 F in a circuit across a potential difference of 1kV . I have a large number of 1×10^-6 F is available which can each withstand a potential of 400V. Suggest a ...
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1answer
142 views

Capacitor discharge: Is gate voltage on IGBT proportional to collector?

I'm designing a capacitive discharge circuit. I'd like to get some feedback before I buy parts for testing. The output should be around 100v and thought an IGBT would work great in discharging the ...
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2answers
137 views

A cubical LC circuit

I would like to solve for currents through inductors and the voltage across capacitances of the attached circuit. I am trying to figure out a correct method to solve such circuits which could have the ...
0
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1answer
42 views

CX-20 Quadcopter Part

One of the ESC's on my quadcopter is missing a component. I am unsure what this component does or where to find a new part. Is it a sort of resistor?? What size? it features no markings that I can ...
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3answers
51 views

Capacitor on line with high frequency digital signal?

Capacitors act as a short for high frequency signals. If I place a capacitor on a digital 5V PWM line or perhaps a motor encoder line does the cap still act as a short to ground for the square wave ...
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3answers
150 views

Grounding a capacitor?

Noobish question. I'm trying to make a dc variable voltage power supply. I will include the schematic which I am trying to build. In the schematic there are two 1000 uf capacitors which I believe are ...
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3answers
263 views

Troubleshooting/debugging PCB

This may be an off topic question, but I'm sure many of you have the knowledge and experience to help out here. A quite complicated motherboard was flexed. The resulting symptoms include cross-talk ...
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3answers
145 views

Capacitor discharging total charge calculation

I need to estimate the total charge that flowed from the capacitor for a short duration of 2ms. I am using an ATmega128 for this. Can someone advise me if analog sample/hold in front of an ADC is ...
0
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1answer
45 views

Minimum voltage rating for output capacitor for use with LTC3525-5 boost voltage regulator

I'm (still) selecting parts to build a 3 to 5V boost DC-DC converter using the LTC3525-5. The board I'm planing to build is based on the typical application shown in page 11 of the aforementioned ...
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1answer
82 views

Why do we take rectangular plates in the capacitor? [closed]

We can take square, rectangular or circular plates in a capacitor. Why do we take rectangular plates in the capacitor?
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2answers
278 views

How does this mosquito zapper circuit work?

For the purpose of learning, I have tear down a small mosquito zapper racket. I am now trying to understand how the circuit is working (which goal is to produce high voltage). (yellow = ...
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0answers
64 views

Poor output efficiency of SEPIC supercap driver

I'm attempting to drive a high power led (3.6V, 700mA, nominal power 3W) from a 5.4V 3F supercapacitor via a SEPIC (see this question). While I don't have any strict design requirements, a running ...
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2answers
95 views

Dielectric can be insulators?

People say that dielectric should be an insulator so that it can decrease net electric field increasing capacitance.. My question is if the object is a insulator how does the object get polarized ...
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1answer
90 views

Why so many capacitors in design?

I was looking the schematic for programming a standalone AVR chip. I am curious why we need so many capacitors. As far as i know, i know we need one capacitor on the power supply. I don't remember ...
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1answer
271 views

Weakest link in lifetime of electronic circuits

I'm working on a product, a single-board computer with an expected lifetime of 10-15 years, and I'm trying to identify the correct components to focus on for this. So far electrolytic capacitors ...
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2answers
70 views

Why does my laptop adapter output nominal voltage with a broken capacitor?

My adapter broke, so I started my repairs by measuring the output voltage; it was 18V as it's supposed to! So, I figured my laptop charging cicruit was broken, but when I opened the adapter I saw the ...
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0answers
40 views

How can I use a 9v chaser board to run LED strips

a few years ago I bought an LED sequencer circuit board kit. Once assembled you can adjust the pace and the brightness with 2 POTs of up to (I think) 8 LEDs. this board runs off of a 9v battery and ...
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1answer
87 views

What can cause the capacitor to blast? [closed]

I had a problem with my air conditioner. The technician came in and fixed it. But he told me that the capacitor inside it was blast. I want to know what causes this and how to avoid it. Thanks!
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2answers
79 views

Is the value of XTAL load capacitors for ATmega328p @ 16MHz critical?

I'm going to try to assemble an MCU-based circuit using an ATmega328P-PU (Arduino UNO stripped down to essential parts as in this tutorial). I've skimmed over a lot of posts on EE.SE about load ...
2
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2answers
103 views

EL Wire vs EL Panel, difference in voltage and frequency needed?

I am currently researching Electroluminescent Inverters/Drivers for a project. There is many accounts that EL Wire needs a higher voltage and frequency than an EL panel or tape needs. (300vpp vs ...
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1answer
86 views

circuit diagram for uninterrupted usage of a 12volt 1amp device using 12 volt 7ah battery with auto charging and full charge cut off

I have a modem which runs at 12Volt 1Ampere , also I have an UPS battery of 12volt 7Ah. I need to design a circuit so that during power outages my modem works from the battery. also a circuit ...
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73 views

Equivalent circuit of resistor capacitor

I came across a capacitor that has a marking like this: 0.1uF+2x2000pF XY + 2MOhm 220V~ HPF fo 1.6MHz 7.75 560.7 it looks like this one below the only ...
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1answer
60 views

what is this capacitor 220 HFP 1J9

I have a small buck dc-dc voltage converter that has two aluminium body capacitors mounted on the pcb surface. The top reads something like this: 220 HFP 1J9 Here's a photo of it... I want to know ...
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0answers
47 views

Capacitor value in suspected low pass RC sub-circuit

I've got the sub-circuit in the image below which originates from a larger circuit setup we are currently investigating. I suspect it might be a low pass RC based filter and I'm trying to figure out ...
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2answers
64 views

What influences capacitor maximum current handling?

In this answer it is said that the maximum capacitor current handling is "largely a mater of losses", what I can understand that is a factor for maximum dissipation. So, what is the thermal ...
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3answers
385 views

Deciding capacitor value to use in my circuit

I have a power source which supplies 1A at 5V. I am using a switching regulator which supplies 1.3A at 3.3V. The load requires a burst of 2A without reducing the voltage across it than 3.2 V for 477 ...
0
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1answer
101 views

What capacitors do when it is connected in Series and parallel to a AC input

I have seen in many circuits the capacitors are connected in series and parallel with the AC line. What the capacitor actually does when it is in series and parallel. I know capacitors passes AC ...
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1answer
72 views

Three capacitors in a loop and dependence?

I was watching a lecture on State Variables on YouTube here The professor mentioned that "if three capacitors form a loop, the three cannot be independently specified. Only two can be done as the ...
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0answers
87 views

Current through Capacitor, how is it possible? How does it relate to displacement current? [duplicate]

What my professor is telling us that there is no conduction current through a parallel plate capacitor but the current that is passing through capacitor is the displacement current and this phenomena ...
0
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1answer
49 views

Timed Relay Circuit Wiring and Calculating

I am trying to learn electronics and I have a simple circuit in which a button is pressed, a capacitor is charged, then triggers a relay. (With my limited knowledge) I am using a 4.7μf cap and a 470K ...
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2answers
104 views

Low profile capacitor

I am trying to make a 24VAC to 5VDC converter. My constraint is to keep the height of the entire power module to as small as possible (ideally < 5mm) I have the buck converter design with the ...
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2answers
89 views

Replace motherboard capacitor with lower capacitance?

Is it possible and safe to replace a motherboard capacitor of 1800uF, 6.3V with a capacitor of slightly lower capacitance 1500uF and the same voltage 6.3V? My motherboard does work, but it tends to ...
7
votes
1answer
329 views

LTC3525 datasheet states that capacitors must be X5R or X7R, not Y5V. Why?

I'm selecting parts to build a 3 to 5V boost DC-DC converter using the LTC3525-5. The board I'm planing to build is based on the typical application shown in page 11 of the aforementioned datasheet, ...
3
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0answers
56 views

Is it practically possible to use mutually coupled capacitors as we use mutually coupled inductors? [duplicate]

Inductor and capacitor are dual to each other in Physics. One comes from Electric Field Theory while the other one comes from Magnetic Theory; the both theories expose strong duality with each other. ...
2
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2answers
112 views

What actually happens in a RC circuit?

I'm currently working my way through a beginner's electronics book(electronics for dummies) where i am introduced to RC circuits as shown in the schematic below. simulate this circuit – ...
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1answer
72 views

Is white residue on a mobile phone water damage indication

I have bought a Samsung Galaxy S4 mini that burnt from the charging point. When sent to get repaired, they told me it was water damage. Illustrating in a picture some white residue circling a black ...
2
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1answer
124 views

How exactly does a capacitor discharge its charge?

When an empty (discharged) capacitor is connected to a battery, it slowly charges up as one plate fills up with electrons, while the other plate has electrons drawn away from it towards the positive ...