Questions tagged [capacitor]

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

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108 views

Source voltage and capacitance

Does changing the source voltage (i.e. voltage of the battery) affect how long it takes for a capacitor to charge in a circuit? Am I right in saying that since the capacitor charges until it reaches ...
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73 views

Voltage on Source Node

I am trying to analyze this circuit, the cap is initially charged to 3 V, the supply is 3 V. The NMOS threshold voltage is 0.7. Next the voltage at gate steps from 0V to 3V, what would be the voltage ...
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Tantulum cap issues: Xray die construction misalignment & dirty marking

I'm having some tantalum polymer capacitor die misalignment and physical dirty marking problem. I hope that I can get any advice from someone; whether this can impact the functionality of the ...
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87 views

What's the formula that relates capacitance, permittivity and geometric coefficient in the ring capacitor?

I find it hard to calculate the geometric coefficient of a capacitor with two cylindric electrodes and a tiny distance between them, exactly like this one : Does anybody know the exact formula? ...
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2k views

Audio input: stereo to mono and filtering DC

I have to get an audio input from a PCB 3.5mm jack and summing right and left channel into one (mono). Then, I have to filter any DC noise from the input. Resistors are 1kOhm each. This, for now, ...
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340 views

What is the difference between a super capacitor, an ultra capacitor, and an industrial capacitor

What is the difference between super capacitors, ultra capacitors, industrial capacitors and hybrid capacitors? I see these names thrown around but they seem to have blurred definitions. Are there ...
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678 views

Is it okay to connect Supercapacitors as input to Step-up voltage regulator?

I want to use the maximum energy of the supercapacitor for 3.3 powered circuits. Thus, I thought of using step-up voltage regulator like this Can I do this? What are the other suggestions?
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421 views

Ceramic capacitor in High voltage DC link

In motor drive application the high voltage dc link between the rectifier and the inverter usually have: a bank of aluminium electrolytic capacitor a film capacitor near the inverter Is there a ...
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887 views

Replacing ceramic capacitors with film in PSU

Some Behringer Truth B2031 came back from a friend and they're acting up. first thing I noticed was the four .1uf ceramics that are in parrellel with the bridge rectifier diodes have experienced ...
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307 views

Voltage across capacitor in a electrical circuit (LCC circuit)

My networkanalyses book told me that the voltage across the capacitor C2 is given by: $$\text{U}_{\text{C}_2}\left(t\right)=\text{U}_{\text{in}}\left(t\right)+\text{C}_1\cdot\text{L}\cdot\text{U}_{\...
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432 views

Power from a small engine magneto

I have a backpack mister (basically a leaf blower with a water tank) that is powered by a small 2 stroke gas engine. Another vendor sells an electrostatic charger which draws its electricity from the ...
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1k views

Design of a half bridge converter

I am trying to design a half bridge isolated DC DC converter but I am encountering some issues. Is there an effective way to come up with a minimum value of capacitors C1 and C2. In all the papers ...
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572 views

Choosing resistor/capacitor for wiring microphones

I've been researching how to wire up a electret mic and found this to be very common. I can't seem to find any info on what values should be used. Most people use 1k or 2.2k resistors and 4.7uF caps. ...
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3k views

Capacitor in 12VDC motor circuit

I having an interesting issue with some cooling fans that came with a used pop up camper. I'm proficient in electronics and this one just doesn't make any sense to me. These fans are designed to be ...
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45 views

Mathmatically analizing different voltages in a phase changing circuit

I am trying to understand a phase shift oscillator from a mathematical perspective, and to begin I simply took the phase-shifting part of the circuit and am now trying to analyze the voltages as a ...
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149 views

chip resistor/capacitor size vs performance for analog circuits

I am designing one four layer ADS1298 (TI) based analog PCB. Signal frequency is about 1.5Hz to 3.79kHz. It is a four layer board with most of the components and traces on top layer and the ground ...
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6k views

Identifying shorted capacitor on laptop motherboard

Background: My Asus U47A laptop stopped charging or running off the AC adapter. With the help of diagnostic tips on the internet, I found the culprit to be a faulty ceramic cap near the input jack ...
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146 views

Dicharge a Photoflash Capacitor in a coil

I am trying to do the coin tosser according to this pdf (result here) So the circuit is supposed to be this one: simulate this circuit – Schematic created using CircuitLab However when I did ...
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253 views

Latching and Momentary Combo Switch

I am looking to recreate a switch circuit I have seen on an intercom system. The switch allowed for two functions, while using one momentary switch. When the switch was pressed and emetily released, ...
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98 views

Capacitor failure

Hi Attached line drawing of my circuit, Inverter produce single phase high voltage, then this high voltage AC step down to lower voltage than it rectified by diode then output goes to a resistive load....
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84 views

Is 'RFI' a term in active usage, or is it all 'EMI' now?

I'm studying capacitors in some detail just now, and one of their typical uses, of course, is to bypass high frequency interference at sensitive circuit inputs. I want to get my terms straight, and ...
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837 views

Amplifier overheating - how to find out if A671 PNP transistor broken?

I have a beautiful old Wega V 3840-2 amplifier. However, it has suddenly given out. I have some basic tools (soldering tools + multimeter: I'm a mechanical engineer, so I'm afraid I don't have my own ...
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442 views

capacitor derating

I am trying to study the effect of temperature on a set of capacitor (the parameter being voltage). In other words , I am looking at how the voltage rating of a capacitor is aeffected with variations ...
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585 views

Can I use a capacitive divider to run an AC/DC converter from a higher voltage than its rating?

Suppose I have an AC/DC converter rated to run from 120-240VAC, and I want to run it off 480 VAC. I think I should be able to put two capacitors in series as a voltage divider, and run the converter ...
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317 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 turned ...
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232 views

State Equations

Please can you help me in finding the state equations for the circuit below? My problem is the two capacitors. How will we cater for the second capacitor? I only know problems with 1 capacitor and 1 ...
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1k views

Finding equivalent capacitance between P and Q

Figure below is the schematic diagram ,there we need to find the equivalent capacitance I know that this is a straight-forward question for most of them, because many of you are expert in the field, ...
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141 views

Designing a high intensity flash attachment for airsoft rifle

Dear readers of this community, I've been looking into starting an electrical project and in my research I've often came across this community. Because none of the topics fully covered my question, I ...
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267 views

Supercapacitor discharging

I had bought a Maxwell ultracapacitor (this one) rated for 1200F at 2.7V. Its ESR according to the datasheet should in ballpark of 0.4 milliohms. It got delivered today and is undamaged and new by ...
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1k views

From RLC prototype to signal flow graph

This simple 3rd order low-pass circuit simulate this circuit – Schematic created using CircuitLab can be described with the following 3 equations: $$-V_1 = \displaystyle \frac{-1}{sC_1} \left(...
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351 views

Voltage Doubler Circuit

I currently have a 25 stage voltage doubler circuit I am using 50 0.1 uF x2 suppression capacitors, 50 1N4007 Diodes, and a 20 Mohm current limiting resistors at the final emitter stage. I am using ...
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91 views

Cycling peak load trips genset

I have an application where a cycling peak load from a 40hp motor is regularly tripping a 65Kw genset. Here are the details of the configuration: 65Kw Genset powered by a natural gas engine 40hp pump ...
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760 views

How does this circuit with three transistors work?

I don't understand how this circuit works. Its a clap switch circuit with transistors. I would appreciate if someone could explain how the current flows through the circuit and which transistor turns ...
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159 views

Potential difference in a capacitor

As I simulated the circuit below, it shows that the potential difference across Cx is the amount of potential being stored on C3 and C4 during charging phase. How do we get the potential difference of ...
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112 views

Charge conservation

How can I apply the theory of charge conservation for this charge pump circuit. Specifically on the pump circuit. How do I get the charges on the capacitors?
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249 views

Are polymer tantalum capacitors safe for use in new designs?

I want to expand this post to cover polymer tantalum caps. In my application I have an older switching regulator that outputs 24V and needs large output capacitance (220uf), so ceramic or polymer ...
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319 views

what is the best way to charge a capacitor bank from an SLA battery

I need to charge a capacitor bank of 25 2.5v 55 farrad capacitors from a 2v 200Ah gel cell SLA battery, and modify the discharge time so that it discharges at 150Ah. I was wondering what the most ...
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49 views

Do I need more capacitance for my crystal?

I've used the formula "CL = (C1 * C2) / (C1 + C2) + Cstray" (where C1 = C2) to calculate the capacitors I need for my board. CL is 18pF, I ballparked Cstray at 5pF, meaning I should use ...
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137 views

Difficulties with capacitor circuit analysis

I have been given this question by one of my lecturers and have been having difficulty with it. I was wondering if anyone could help me. In the circuit of Fig. 1, switch SW1 has been closed, and ...
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279 views

Capacitor/varistor replacement

Can any one tell me what I would need to replace this yellow disc. I have another board that this part has burned up, and I need to find a replacement. The manufacturer is Buss, however I cannot ...
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112 views

Is it safe to add a big capacitor in parallel to a power supply output?

I have an application which uses a 1000W standard PC power supply, drawing continuously around 300W. However, sometimes there are short power surges of ~800W or more, which I believe triggers the ...
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48 views

Charging capacitor trips breaker

I am designing a circuit to drive a DC motor from rectified mains voltage. For that, I have added a 1200uF capacitor. My problem is that this circuit is supposed to work on a user's home power plug, ...
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77 views

What is meant by "Kelvin connected to capacitor" in layout terms?

In the MPS5496 PMIC layout guidelines on page 37, they mentioned that you should connect the feedback pins to the buck output capacitor "kelvin connected." What does that mean? Can anyone ...
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63 views

Selecting an input capacitor for a large power PCB

I am building a power PCB which will take in 48V (at a max of 10A) and convert it to 5V (using a buck converter) and 7.4V (using a separate buck converter.) I am adding in reverse polarity protection ...
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What is a Ladder Switched Capacitor?

I have recently read several papers with LSC on it (I'm taking care of my Mom 24/7, so I can't find them right now). Are Dickson and Cockroft-Walton considered Ladder, or am I off? Thanks.
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58 views

Blower motor control with disconnecting run cap?

I am reverse engineering a multi-speed blower controller and perplexed by my results. The blower (230V single phase 250W rated) is the heart of range hood. The schematic on the controller end is ...
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38 views

Voltage droop and bulk capacitor selection

I have a fundamental question regarding bulk capacitor selection for a pulsed power circuit. Assuming I am switching a 2 kohms resistive load using a 2 kV power supply at a switching frequency of 10 ...
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How do I determine what capacitor to use for motor driver decoupling?

I am designing a control module for model trains that uses an ESP32 to control everything. Due to the nature of this, I have very strict dimension and thermal requirements. (Must be able to run for ...
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43 views

Transformerless capacitor based power supply Proteus simulation

I have a small DC current requirement of less than 30mA @ 24V DC from 230V AC main source. Instead of using an expensive transformer based power supply I am trying to implement a low cost voltage ...
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38 views

Ramping up Regulator Voltage on Switch On

I'm currently trying to design a supply using a low dropout regulator capable of 1.5 A that has a high capacitance of up to 1 mF at its output. To limit inrush current I would like to ramp up the ...

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