Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [capacitance]

Capacitance is the ability of a body to store an electrical charge.

Capacitance is the ability of a body to store an electrical charge. Any object that can be electrically charged exhibits capacitance. A common form of energy storage device is a parallel-plate capacitor. In a parallel-plate capacitor, capacitance is directly proportional to the surface area of the conductor plates, and inversely proportional to the separation distance between the plates.

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Capacitance between Earth and Moon

Is there a capacitance between the Earth and the Moon, and if there was enough potential difference, could a discharge strike occur?
skyler
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How can capacitance values be determined from a cyclic voltammogram?

I am reading an article (Khomenko, Electrochimica Acta 2005, 50, 2499-2506) that investigates the capacitance of carbon-based electrodes for use in supercapacitors. In particular, they use cyclic voltammetry (CV) to determine two types of…
Andrew
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Why did the capacitor blow up?

So my friend and I were working on this project which required capacitors. We needed to charge a capacitor with the following rating: 100microFarad, 400V. When we connected it to a 220V AC source (peak voltage 311V) it went boom. We thought we had…
Kunal Pawar
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Measure picofarad capacitances accurately

I need to measure or sense capacitance from 0 pF to 5pF, with an accuracy of 0.1pF or better. I know capacitance to digital convert chips claim to do that, but is there a simpler/easier way to breadboard a circuit to measure these ultra-low…
David M
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Capacitor value denoting

Hello I'm trying to understand the value in microfarads of capacitor labelled, C791 103(2) And how to calculate if the SI unit is not given thanks.. diagram below One more question if you don't mind please... what about resistor? It's value is…
Dan
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How do precision differential levels achieve such high accuracy

As you do, I was watching a video about levelling granite surface plates used in precision machine shops and labs. They're ground and lapped to a high level of flatness (I think AA plates are flat to within around 0.005mm) and a key tool for this…
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Detecting when a barbell touches a person's chest

I am trying to detect the moment when an Olympic barbell touches a person's chest during bench press. I have been trying to detect a change in capacitance to do this. The problem is the person's hands are already on the bar, so there is not much…
Philip
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Capacitance equation understanding

Does anyone know where the bottom equation is derived from? Why is it 8V/9V? Source: Mouser - Everything for Capacitive Power Supplies by TDK
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Simple series capacitance circuit

I am a semi-retired Electrical Enginerr, and this question has me perplexed. I don't need any info on capacitors, series calculations, transition effects, etc... Here is the complete question but I'm just rusty on the charge distribution at…
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Volatile capacitance values at low frequencies

When I measure the capacitance of two cables I get very volatile values if I go to lower frequencies like 500 Hz. The capacitance is about 50 nF. Why does this happen?
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Capacitors in series

Okay so I'm looking at RF designs and I've come across a couple of designs which need 2p2 caps. I've seen C1.C2/C1+C2 being plugged into a function (the tank part of the circuit) which gives a lower capacitance for the circuit i.e. C1 && C2 == 27pf…
Paul Sullivan
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Flashing LED circuits

How does the current flow through this circuit and thus how do the components work together to cause the flashing LED? I know the basics in that the current first charges the capacitor which consequently turns on the transistors, however I don't…
Lisa Ban
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Calculate capacitance from current / voltage (dV, dI & dT) pulse

How to calculate the capacitance value based on a current and voltage pulse ? From some data, I would like to calculate the capacitance value of a specific point based on a current and voltage pulse. Unfortunately, all the resources I could find…
Damien
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How to calculate the total capacitance of many connected parallel traces

I have a PCB with 60 or so traces in a parallel geometry such that the traces are connected in an alternating pattern as in the picture. My question is, what is the correct way to calculate the total capacitance of this board? My first thought is to…
Michael
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How to measure small capacitance with high parallel resistance

I have a sensor that can be modeled as a capacitor and resistor in parallel. The problem with this sensor is the resistance is on the order of 10's MOhm and the capacitance (we believe) is single pFs. I have tried using a resonant circuit to find…
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