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

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2answers
42 views

Measuring small (and small changes in) capacitance

I would like to measure the capacitance between two random pieces of metal. Also, I would like to monitor the changes in such capacitance as people walk by those metal objects. Can a cheap ...
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2answers
68 views

Physics explanation of charging time by increasing dielectric constant

I am having a problem understanding in physics of the relationship between charging time and dielectric constant of a parallel plate capacitor. I'd like about physics aspect not based on time ...
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1answer
56 views

Understanding the Difference Between Two Capacitance Sensors

I'm slowly beginning to understand more about how these work thanks to answers I have received on this site. I believe one area of confusion for me has been I've looked at two differently designed ...
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0answers
45 views

Finding the effective switched capacitance in Intel processors

I need to able to calculate the power consumption of an Intel processor using the equation, P = C * (V^2)*f where C, V and f are the effective switched ...
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1answer
59 views

Can I use any capacitor for a 2 phase AC motor?

So recently I got my hands on an old pump motor, unfortunately the connection diagram is missing. I have already determined this is a 2 phase motor, and that in order to make it work I need a ...
-1
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0answers
31 views

Room insulation material to be low-static, or non-static environment [closed]

I am researching a material that needs to be low-static, or non-static environment to insulate a work room. I've researched the floors and tables, but I am wondering about using an insulation material ...
0
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1answer
77 views

Design challenge: Detect finger-to-finger touch with nothing in between

I'm trying to build something quite challenging and seem to be getting nowhere. Maybe you'll help. I'd like to detect a touch of two naked fingers with no materials or sensors in between (simple ...
1
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1answer
54 views

Capacitor Help -> Will stacking of dielectric and metal foil increase capacitance?

I'm new to this forum, so forgive me if I am missing something. I am building a capacitor, and I want to know if stacking dielectric and metal foil will increase the capacitance, and if so At what ...
2
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0answers
71 views

aluminum foam capacitor

Sorry if this question is in the wrong community but anyway, why don't people use foam aluminium for capacitors? Its got a large surface area to my understanding (however probably not as much surface ...
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1answer
54 views

Power factor correction AC motor

Four 240v, 50Hz, 16kW motors are installed in a factory. Each has a power factor of 0.86 lagging and efficiency of 78.2% while running. Determine the shunt capacitance required to deliver unity power ...
-1
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0answers
13 views

Electrometer mode of universal amplifier [closed]

Explain why a high resistance is used in electrometer mode. A voltmeter can also be connected to amplifier but what is the use of high resistance in universal amplifier electrometer mode. The circuit ...
4
votes
2answers
112 views

Supercapacitor with a rated voltage value greater than 2.7V feasible?

I've been researching into the development of electrical power units for Automotives (motorsports in particular, as I participate in my Uni's Formula Student team) and have started by looking into the ...
2
votes
5answers
141 views

Why is charge the same on every capacitor in series?

Why is the amount of charge on every capacitor in series equal, regardless that capacitance values of capacitors are not the same? What really happens here so they are the same? simulate this ...
-1
votes
1answer
51 views

What is my capacitance? [closed]

I have a current measurement of 300mA on an MCU evaluation board. If my power supply is 19V or 12V what capacitance do I need to use in order to limit the voltage fall to 5V?
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1answer
45 views

Why is the input pin to my multiplexer considered a capacitive load?

I am currently using CD74HC4067 multiplexer in my design. I had trouble with my input signal and therefore conducted an experiment by measuring the input resistance of my multiplexer as the frequency ...
2
votes
2answers
379 views

Using an Arduino to measure wire capacitance

I wanted to use an Arduino as a capacitance measurement device for a coaxial wire. I started at measuring the wire capacitance using digital multi-meter UT58B. I turned the knob to 2 nF and then ...
0
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1answer
280 views

smallest possible length of copper wire, where I can measure capacitance via multimeter

I am a new highschool physics instructor and I want to show to my students the basic concept inside capacitors and how they work. I plan on showing them 2 simple copper wires side by side , ...
0
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1answer
45 views

how to detect the changes in capacitor?

I have capacitor in the picofarad range , that capacitor will change slightly ±5 picofarad ,how can i detect that change ..any circuit or idea the capacitor is not normal capacitor, i used two ...
1
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1answer
66 views

Is it possible to get an exponential capacitance curve from coded dip switch

I have a capacitor that controls frequency for a specialty IC with the relationship \$F \propto 1/C\$ I want to be able to get a number of frequencies in evenly spaced intervals. Currently I have a ...
1
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2answers
77 views

How is the electrical bus capacitance for I2C trace calculated?

i am trying to learn how to calculate the bus capacitance of an I2C tree with a master and multiple slaves. For example, in this document from TI, it shows how to calculate the value of the pull up ...
2
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3answers
60 views

High capacitance electrical capacitors

Are high capacitance electrical capacitors capable of storing energy instead of using a battery. If so would they be able to hold 7 kws of usable energy for domestic home use?
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3answers
73 views

Solving Vout for a differentiating op-amp with added resistor?

I searched through old posts and didn't find a direct answer to this - there were practical explanations but no circuit math. I am to solve the \$V_{out}\$ value for a differentiating op-amp. I know ...
2
votes
1answer
67 views

How to measure parastic capacitance of a trace

I have a 24 MHz, crystal on my board and datasheet of IC defines the load capacitance between 5-9pF. The reference design I follow don't use any load capacitor. My traces look like this: shorter ...
15
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6answers
1k views

LC circuit, bigger L than C, or bigger C than L?

So if I want my LC circuit to resonate at 20MHz, I just use the formula, \$F=\frac{1} {2\pi\sqrt{LC}}\$. Using available inductor and capacitor values, there are lots of different possible ...
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0answers
28 views

How to estimate ripple current for PWM loads?

I'm buying some caps for a PCB which I'm designing, and I'm not quite sure how to estimate the ripple current they need to be. This PCB is intended to switch about ~15A from 12V to 24V at ~100kHz. ...
2
votes
1answer
85 views

How do I read capacitor data sheets to best evaluate a replacement capacitor? [closed]

I'm looking at two capacitor data sheets for some blow caps in my KBNBX-LA motherboard. Here is a pictures of the caps on the mobo. The caps read Rubycon 6.3v3300uF MBZ. I was able to find these ...
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1answer
39 views

Capacitance of convoluted circuit

What is the capacitance of this circuit if S is closed? AFAICS, Rules for capacitors in series or parallel can only help to simplify the problem down to ...
4
votes
1answer
251 views

Why Increasing Collector Voltage Reduces Collector-base Capacitance

I'm looking at some transistor radio circuits and the book I'm following makes the following statement with regard to AC gain: "By raising the DC voltage at the collector, the internal collector-base ...
5
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4answers
193 views

Self capacitance of an isolated object

A few times I've been reminded that an object can have self capacitance and it's just not registering with me how this can be so. I'm sure there's a good explanation. Here's the explanation I am ...
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votes
1answer
44 views

Formulas for Specific Capacitance Measures [closed]

I am designing a charging and discharging capacitor circuit for my power harvester. What I am looking for is the time it charges and discharges respectively. When I lookev over wikia and google. ...
1
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1answer
58 views

Do the test operator must hold an antena during the EMC immunity test?

We are doing EMC test the Capacitance sensing Touch panel, pursues immunity issues versus 28MHz noise. We do it in 2 methods: (1) The operator is holding an antenna(which generated 28MHz noise), and ...
2
votes
3answers
278 views

Understanding the Apple 1 power supply

I'm trying to understand the schematic of the Apple 1 computer power supply. Nothing surprising at first sight. Two power transformers (117 VAC -> 10 VAC / 117 VAC -> 28 VAC), two diode bridges, and ...
3
votes
1answer
52 views

Troubleshoot load capacitance (crystal not starting)

I am using a MAX11060 ADC in a project, I have established SPI communications and am able to read and write registers, however I am unable to get any readings, I believe this is due to the crystal not ...
8
votes
2answers
203 views

How do I size the coupling capacitance for a SEPIC converter?

The app notes I've seen for a SEPIC converter1 all tell me to size the coupling capacitor for ripple currents and voltages. I haven't seen one that tells me how to size the capacitance. Obviously ...
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1answer
94 views

Is my oscilloscope affecting my tuning circuit?

I am building an AM Radio and I have constructed a tuner circuit. See below. simulate this circuit – Schematic created using CircuitLab However, I cannot use this circuit, because even ...
3
votes
4answers
790 views

Are too high capacitance capacitors “bad” for the circuit?

I am trying to learn basic circuitry and I've been looking into capacitors and their uses in different areas. When looking at capacitance several different sources say that circuits might ...
8
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3answers
220 views

Does someone have a non-textbook analogy to explain elements of a circuit?

I was wondering if someone could explain with analogies what inductors, capacitors, transistors, diodes, and op amps do? I understand the basic idea; I'm currently an Electrical Engineering student. ...
3
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1answer
64 views

Power MOSFET capacitances

I am trying to understand the Power MOSFETs. I am wondering about the usefulness of the Ciss, Coss, Crss capacitances which can be found in the datasheets – aren’t they small signal capacitances? If ...
1
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3answers
118 views

exactly why does a capacitor build up charge when hooked up to a battery?

I understand how the capacitor "holds" charge. If one plate is positive, and the other is negative, the particles are attracted to each other. Connect both sides by a wire and instant flow. However, ...
0
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0answers
29 views

MOSFET capacitances - current versus frequency plot

How can capacitance be calculated or estimated from a current versus frequency plot? I am trying to measure gate-source, gate-drain, gate-body capacitances on a MOSFET and I was advised to plot ...
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0answers
25 views

Charging Current in a Ungrounded Neutral System

Does charging current flow into the ground,under the healthy conditions,in case of isolated neutral(or ungrounded neutral) system ?
0
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1answer
84 views

Step-down converter input and output capacitors

In the below pictured circuit for the MC33063 by TI, how important is the capacitance of the inpu-output caps? I understand why they're there, I don't know what the recommended capacitance is derived ...
0
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1answer
95 views

capacitance to voltage conversion

I need a circuit to convert variable capacitance value to considerable variable DC voltage. Capacitance value range = 0pF ~ 20pF DC value range needed = 0V ~ 6V Please explain in detail as i am ...
2
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1answer
73 views

EMP Protection of Ethernet Lines

I'm currently working on protecting 1000Base-T Ethernet lines from EMP using filter connectors such as described on page A-7 of this doc: ...
1
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2answers
64 views

Electrolytic Capacitor Voltage Rating vs capacitance

I have always believed that it was ok to replace a capacitor with a slightly higher voltage rated one. eg 16v with 25v.Going higher than this would risk the capacitance value being out at the working ...
0
votes
1answer
77 views

Testing Capacitors - Differing Results Each Time One Is Tested?

I have a bust LCD TV - I've already ordered a replacement but am interested in using the broken TV to learn a little more about how these are put together and if I'm lucky fix it to have as a spare. ...
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0answers
30 views

Why cyclic voltammetry recquires three electrodes?

From Wikipedia: The potential is applied between the working electrode and the reference electrode while the current is measured between the working electrode and the counter electrode. Why ...
0
votes
2answers
102 views

Voltage across a capacitor.(steady state)

At the circuit above I built a simulation that shows the voltages on both sides of the capacitor(in red and green). However the voltage measurement shows that the voltage on the 3u capacitor is only ...
0
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1answer
81 views

Can adding power storing capacitors burn up an adapter?

I have been working on a circuit board for an Arduino project. It contains an LCD screen, linear regulators and several relays. In an attempt to remove voltage spikes and dips, I have added several ...
1
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1answer
96 views

mosfet switching high frequency ac

I am trying to use MOSFETs to switch AC power. Here is my test circuit: simulate this circuit – Schematic created using CircuitLab If I put DC or low frequency ( < 1000khz) across the ...