Questions tagged [capacitance]
Capacitance is the ability of a body to store an electrical charge.
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A 555 timer changes time when you touch it?
I designed a simple 555 astable 50% duty cycle square wave generator, assembled in China on SMT PCB. It works well: Except when you touch it, or even put your fingers near it, the timing changes ...
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3 phase motor in Steinmetz connection on a single phase supply direction change problem
I want to run a 3 phase induction motor on a single phase power supply.
I'm aware of the low operating power & low starting torque in this configuration.
My load & duty cycles are also not big,...
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How can I find the steady state of current I with sinusoidal voltage source?
I am reading the book Electric Circuits 10th Edition from Nilsson and Riedel. In page 321 has a problem that seems easy but I find a difficulty to solve it.The problem states:
A 90 ohm resistor, a 32 ...
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Online measurement of capacitance of open-load AC cable
I would like to detect whether a three-conductor (L1, N, GND) AC cable's length has been increased – for example, when a connector with attached cable is inserted into a standard/unmodified connector. ...
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Derive a State-Space Model for an Electric Circuit with three Energy Storage Components
I want to model the shown circuit diagram with a state-space model. However, I cant solve it since I obtain four unknown variables while only three of the derived equations are linear independent. ...
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Can I measure pinholes in a dielectric layer using LCR meter?
I have a thin dielectric film (~1 um) and I want to measure the quality of the film in terms of not allowing leakage current through pinholes. Can I use an LCR meter for this purpose? If yes, how? If ...
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Doubt about the capacitor in a equivalent circuit (ion chambers)
I'm delving into the topic of ionization chambers, but as someone without a background in electrical engineering, I'm finding the equivalent circuits a bit challenging to comprehend. Specifically, I'm ...
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Stray Capacitance in a Lithium-ion battery pack casing
I made a Lithium Ion battery pack for a diy car project using cylindrical cells and observed something interesting. First, I'll lay out the pack details:
Configuration: 1p96s
Max Voltage: 403.2V
...
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Common-mode capacitance of operational amplifiers as defined in datasheet
The common-mode input capacitance is modeled as Ccm/2 on each operational amplifier input in https://www.allaboutcircuits.com/technical-articles/input-capacitance-analog-circuits-how-to-compensate-...
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Find needed capacitance of charged capacitor with constant power load
I would like to discuss the circuit depicted in the screenshot of a simulation in LTspice. Let's assume there is a capacitor charged to V0 = 25 V that is connected ...
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Output load capacitance vs max input load capacitance
I am currently in the process of building a frequency divider circuit. To realize a lower frequency of 3.072 MHz. I use the: ECS-TXO-3225MV-122.8-TR
For frequency division and reduction I use D-...
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Why do my MCU's capacitive voltage divider results change with different power supplies?
I've started experimenting with the onboard capacitive voltage divider inside the PIC18F47Q43. I've had success getting it up and running and getting usable results. This is the block diagram of it:
...
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What is the charge time of a capacitor C that is already at Vc volts, and I want to charge it to V volts? Vs = 5V the supply voltage
In code, I've been using this formula:
charge time t = -ln(1 - Vc/Vs) * R * C
where R = 1.0 here so we can ignore it. This is derived using Kirchoff's laws etc from a voltage source attached directly ...
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Formula for calculating capacitor balance resistor values
The following formula is generally used for calculating balance resistor values used for overvoltage protection of capacitors in series when the individual capacitor voltage ratings are below the ...
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Capacitance of a system of 2 connected spheres
Consider the above set-up of 2 connected conducting spheres. I am required to find the equivalent capacitance of this system. Now, I know both of them will attain an equal potential in steady state ...
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Voltage drop due to leakage current in capacitors in series
When capacitors are connected in series in a DC circuit, the voltage drop across individual capacitors at and immediately after the initial charging period is inversely proportional to the individual ...
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Eyeballing bus capacitance
I would like to use single-wire half-duplex UART bus to connect together two STM32 controllers and one ESP32 module. They all will have diodes on TX and share one pull-up. The wiring uses 2m of common ...
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Will DAC81404 work as as piezo transducer driver?
I am in the process of designing a PCB that will drive a piezo transducer that is split into 4 quadrants with a DAC81404. The piezo transducer will move an atomically sharp tip to probe the surface of ...
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Antenna tuner for 1MHz to 150MHz
I am trying to build an antenna tuner for my 2m (1m + 1m) dipole antenna. It has a 1:1 balun and is connected to a coaxial cable which is connected to my radio with an impedance of 50 ohm. I can't ...
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Calculating capacitor value to mitigate voltage drop
A similar question has been asked here but I'm not entirely sure how to apply the accepted answer to my problem.
I have an ESP8266 Module that draws quite a lot of current when turned on. (I don't ...
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Is there any way to discover the capacitance, voltage rating, and temperature coefficient of these MLCCs?
Is there any way to discover the capacitance, voltage rating, and temperature coefficient of these 3 MLCCs shown in the pictures below using an inexpensive tool I can purchase? What is meant by the 2....
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Does a Tesla coil's secondary parasitic capacitance and top load capacitance add up?
I came to this question recently and suppose it's true that the secondary's parasitic capacitance does indeed add up with the value of the top load's capacitance, but I really want to hear someone ...
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Calculate needed capacitance
I have this application which requires 18VDC as well as 12VDC. To get 12V I have designed a buck converter circuit which can supply up to 2A.
The problem:
The 18VDC (3.33A) supply may suffer from ...
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How can I separate gate to body cap from gate to source cap of a MOSFET?
I am extracting CV parameters of MOSFET Level 1 Model.
I used 2N7000 MOSFET for a measurement.
The body pin is attached to the source pin, and I would like to know how I can separate Cgb values from ...
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How do I factor the impact CDS has on the charge required by my gate driver to charge CGD during the miller region of the turn-on of a mosfet?
So as I understand it, with a resistive load, when the voltage at the gate relative to the source is increasing from VTH to VGP, it seems that the value of VGP is the voltage at which the current ...
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Are many capacitors in a row in parallel really needed for an audio circuit?
I get that smaller capacitors have lower parasitic inductance and resistance compared to larger capacitors. And lower parasitic impedance allows the smaller capacitors to be more effective at ...
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Pin inductance vs pin capacitance in determining rise and fall times
I am a beginner in digital electronics and VLSI.
I know that pin capacitance is an important parameter in determining the rise and fall times of logic gates and ICs.
This is supported by my intuition ...
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Capacitance for which the ratio of the input and output voltage is independent from the frequency
I have the following circuit with resistors and capacitors in parallel (see Picture 1):
I have to determine the capacitance \$ C_1 \$ in such way that \$\frac{u_e}{u_a} = 1 + \frac{Z_1}{Z_2} \$ is ...
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How to dissipate charge stored in a capacitor on demand
Building a 5V circuit board to switch on and off a 120V pump by means of a SSR with feedback to LEDs to indicate the system state - Pump On/Off and Temp High/Low.
Planning to measure the pump state ...
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Need help understanding how capacitive touch sensor works
I watched this tutorial here (Explanation is from the time stamp 01:58 onwards): https://www.youtube.com/watch?v=3KQd9F0P6PI&t=283s
and I'm having trouble understanding the concept. I get the ...
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**FINAL UPDATE** I'm getting closer to a workable circuit for this device?
FINAL UPDATE
I think the power supply is squared away accept for some caps and resistors. Thank you for sticking with me. One question:
There are two thermistors (one for each battery pack) that are ...
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KVL contradiction in LC circuit
Let's write down KVL in direction of current flow for an LC circuit.
We have 2 cases:
a) \$-\frac{q}{c} + L\frac{dI}{dt} = 0\$, which is wrong.
b) \$\frac{q}{c} + L\frac{dI}{dt} = 0\$, which is the ...
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Maximum load capacitance and rating for fusing for bridge rectifier
I'm looking for a replacement for an old bridge rectifier and I've found one (Vishay B80C1500G), but I'm curious about two parameters of the bridge rectifier:
Maximum load capacitance
Rating for ...
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Does a battery's charging current depend on its capacity?
I'm learning about charging 3.7 V Li-ion batteries.
I'm not sure what the charging current should be for a single battery, let alone for batteries connected in parallel.
My question is related to ...
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Estimating distributed capacitance from frequency sweep
I have a top/bottom spiral planar coil with the following frequency response. Is it correct to assume that the distributed capacitance is the sum of the capacitance values calculated over all the ...
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What are NMOS level 1 CV equation and its main parameters?
I was asked to perform MOSFET CV modeling. I looked through some papers, but I still can't clarify what the CV model equation for a level-1 NMOS is, and I am also not sure what its main parameters are ...
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How to estimate electrolytic capacitance from foil area
I opened a failed 1000 μF electrolytic capacitor. It contains 2 foils coiled with paper and some wet dielectric.
With reasonable assumptions (to me), I can not derive marked capitance from this ...
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Does the capacitance of a Schottky diode depend on switching frequency?
In datasheets they write '1 MHz' in the capacitance vs voltage figures. For example:
I suppose it is some sort of a standard to measure the capacitance at 1 MHz, but is there a dependence of the ...
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Differential capacitance change measurement (sensing) with 74LS628
I'm researching the possibilities to accurately register the capacitance changes of a big metal plate (area 10 m2) to the ground (GND, yes - earth, soil). It varies around 100-200 pF.
For now I'm ...
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Need help with validation of the design of a capacitance sensor array for soil moisture measurement
Product Description
The device is a soil moisture sensing and analysis device that uses capacitance sensing technology to help manage soil moisture in your garden. One probe set at the bottom of the ...
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How to find resistance, inductance, and capacitance of a load/device
I'm planning to make a proper simulation of a circuit. Before the simulation, I need information about the load (resistance, inductance, and capacitance).
Example: the load is a CPU. range of wattage ...
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How do I measure the capacitance of a 0603 capacitor which is in the order of pF?
My multimeter does not have pF resolution and I am not able to find any tools which can measure a pF capacitance.
My goal is to identify the capacitance of a 0603 capacitor that I have removed from a ...
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How does capacitive loading and inductive loading differ from resistive load?
A voltage source is loaded when current is drawn from it. Usually we have voltage sources in circuits and not current sources. A resistive load draws current from a voltage source that is a function ...
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Concentric Tube Capacitive Fluid Level Sensor Troubles
I'm a mechanical engineering student working on my senior design project. We are trying to measure a fluid level inside a tank using a capacitive sensor. Originally, the team had designed a parallel ...
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Are two capacitors connected together considered to be parallel or series?
If both ends of two capacitors are connected to each other but in such a way that the positive end of one capacitor is connected to the negative end of another capacitor, do we say that the capacitors ...
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Why does a smaller capacitance equate to a larger voltage drop physically?
I was hoping someone could explain practically/physically why a smaller capacitance has a larger voltage drop than a higher capacitance. The equation is V=Q/C, so based on that it's very easy to see, ...
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How does the FDC1004 (capacitance to digital converter) measure capacitance?
I am using the FDC1004 and wondering how it exactly measures capacitance. The datasheet is not explaining much. An associated application note contains a little more information, but still very little ...
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Can series capacitors reduce guitar cable capacitance without signal loss?
Recently, I was reading about a so-called zero capacitance guitar cable pitched to eliminate resonant frequency shifts when using higher impedance passive guitar pickups. The company claims their ...
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How does this capacitance measurement op-amp circuit work?
I'm studying this scientific paper where a capacitance measurement is done with the circuit shown at page 3. For simplicity I reported it here:
A sinusoidal signal is applied at the input through a ...
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Miller capacitance in MOSFET
What is Miller capacitance? Is Miller capacitance a parasitic capacitance in a MOSFET?
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