Questions tagged [capacitive]
Based on the usage of capacitors, condensators. Alternatively, utilizing the derivative of signals.
278 questions
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What is capacitive loading? (Intuitive understanding)
I have read about capacitive loading, but what does it actually mean intuitively?
I just asked this question so as to get an intuitive answer and also know what should I understand when one says that ...
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Line to Line voltage in a three phase circuit with three loads
So the first load is a balanced, purely resistive one. The second one is unbalanced, and the third one is balanced. Diagram looks like this
For the first load, I'm expecting to get line to line ...
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Capacitive load of PSU
I see many power supplies have a parameter called max capacitive load. In this case for the below PSU, it is 2200uF.
What does this mean exactly?
I cannot measure the capacitance of the load easily so ...
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Do projected capacitive touch panels need side clearance to ground metal?
I need to use a TFT module with an integrated capacitive touch. The TFT has it's FFC and the touch controller has its own, with power supply and an I2C interface. Quite standard, I think, since every ...
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How do self capacitance touch screens work?
I get how mutual capacitance touch screens work, by changing the dielectric around the pairs of electrode and "stealing" electric field lines. Connection to earth of the object (a finger ...
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Using capacitive touch screen without human hand
I'm trying to learn more about how to engage a capacitive touchscreen without using a human finger. Full disclaimer I'm in mechanical engineering (notoriously known to have difficulty comprehending ...
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Soil moisture sensor - Interdigital (FEF) vs Coplanar
I am working on the development of a low cost capacitive soil moisture sensor which uses dielectric permittivity changes to estimate moisture.
I found that interdigital capacitor based on FR-4 has ...
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Choosing component values for capacitive accelerometer readout-circuit
I am trying to design and simulate a capacitive accelerometer.
The idea is to model the sensor as a capacitance bridge to which an AC
signal is inserted. Each arm of the bridge acts as a voltage ...
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Capacitance on the output of an op amp
I have read a lot about capacitive loads on the output of an op-amp and the possibility of unwanted oscillations and instability. my knowledge on phase margin and frequency domain analysis is a little ...
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Differential capacitive transducer
I would like to design a differential capacitive transducer to measure the capacitance change in an accelerometer.
I cant seem to understand, how to demodulate the signal and keep the actual DC value....
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Inductive or capacitive load?
Here I have a series LCR circuit with resonant frequency greater than 200Hz. Is there a way to know whether this circuit is an inductive or a capacitive load?
Edit: The only additional information we ...
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Grid is capacitive in the evening
what does this term mean? "the grid in the evening is capacitive"?
I work at a company and we are working on integrating a battery storage system on a utility scale for peak shaving of solar. When we ...
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How to know if an opamp can drive capacitive loads?
There has been a lot of questions about how to stablise opamp circuits driving capacitive loads. However, I know there are some op amps that are designed to drive capacitive loads but I am struggling ...
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Help with capacitive touch button output configuration
Can someone help me with the basic working of this capacitive touch switch? I know it isn't very complicated but I just can't get over my brain block of what actually triggers when the button is ...
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ESP32 touch sensor outputs unstable values
I am trying to implement touch functionality of esp32 development board to toggle a led. But on uploading a simple touch detection sketch, output have spikes i.e. usually value remains near 100 but ...
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sensitivity and frequency-stability of capacitor-based oscillator circuit
I am constructing a capacitive transducer which changes capacitance as a function of changes in other physical properties. The capacitance is about 0.1~0.5 nF range, and I want to detect about 0.05% ...
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How do capacitive touchscreens really work?
I have a bit of trouble understanding the electrical laws which apply when I touch a capacitive touchscreen with my finger.
Apparently, there is an electric current running through electrodes below ...
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Sensor to detect collision or intervention
I am currently working on a project (robotic arm) where I need to detect human collision with the robot. I need a sensor that should be flexible, detect human intervention in the workspace of the ...
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Bad capacitive touch screen sensitivity when running on battery, without earth
In short:
I´m working on a battery driven handheld device with capacitive-touch screen. The capacitive-touch works perfect when the PCB connected via USB, but it loses sensitivity when driven by ...
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Correct design of capsense controls
I am trying to design a PCB with some capacitive controls. My first iteration did not seem to work well:
This was a 2-layer 1.6mm board with one circular control, and 5 buttons. The board is 48mm ...
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Capacitive voltage divider question
I see a few discussions on this but cannot really find the "definitive" answer.
I am building an audio amp and have two modules, one requires 18-0-18V AC and the other 12-0V AC, the 12V ...
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People detection in large rooms using antennas
After coming across a 2004 installation by Carsten Nicolai titled "anti" where he used a theremin as an element for presence sensing, I was wondering if this principle could be extended to ...
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Capacitive load in inverter
I'm trying to understand the effect of a capacitive load at the output of an inverter.
And how does it affect the output signal when this capacitive load is high and when it is low?
Could anybody ...
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How to detect which finger touched the mobile screen [closed]
I'm working on a project where I need to detect which finger touched the mobile screen i.e capacitive screen.
I'm not talking about double finger touch or single or drag and move etc. I'm asking which ...
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Capacitive fluid level sensor design and insulation
This is a question regarding the measurement of a fluid level (in my case water) using a capacitive sensor. Capacitive sensors are a common topic, but I have one specific question: It is necessary for ...
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Adjustable voltage, 1 MHz capacitive biasing
I'm a budding physicist with little electronic design experience and am interested in driving an alternating E-field of adjustable strength within capacitive loads.
Buying a several thousand dollar ...
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Headphone Noise from Laptop SMPS
I have been facing an issue that has been a mystery to me for quite some time, and I wanted to see if someone here can potentially give me more insights on this so I can understand why it is happening....
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LED on lamp outlet flashes when switch is off - is this capacitive coupling charging the power supply? And what to do about it? [closed]
I wanted to connect an LED light chain to a lamp outlet in my house in order to turn it on and off using the wall light switch. I have dismantled the 230V to 3V power supply that was built into the ...
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Soft-start design and performant with short-circuit test
I am working on a soft-start for a capacitive load. I using module QSB40024S24 to create 24V output. At first, I allowed the output of the module to connect directly to a capacitor array (21.4mF in ...
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Relay contact sticking while driving a capacitive load
I am using a Panasonic relay (ALQ105) rated for a resistive load of 10 amps 5A at 250V to drive LED bulbs. These LEDs have capacitive circuits in their ballasts and hence draw high inrush current when ...
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How to detect which pins on a pin display are touched using capacitive sensing
I'm working on a project to apply touch sensitivity to a modified pin display (30x30). The goal is to allow someone to interact with the display through their fingers and ideally touch.
We initially ...
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Capacitive load of connecting cable for a temperature sensor
An LM35 temperature sensor is 4m removed from the Arduino to connect it too. The available cable has 4 wires with a diameter of 0.6mm (0.28 mm2 area) as well as a, seemingly aluminum, shield . The ...
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Capacitive touch sensor senses every materials touch
I have a ttp223 capacitive touch sensor. It has three pins, VCC GND and I/O. I left I/O open for test purposes. I connected the VCC to 5V and GND to ground. When I touch the sensor, its led indicator ...
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Grove capacitive fingerprint sensor not working
I have just purchased one grove capacitive finger print sensor.
link.
I am using Arduino Nano and followed there tutorial but the example code isn’t working.
Blue light on sensor never turn to green ...
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Capacitor 250V DC
I have 0.22uF 250V DC MLCC SMD capacitor.
Can I use it for 230V AC main as capacitive power supply?
Your suggestion will be helpful for me.
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How can human finger pressure be measured?
I am dealing with a situation where a patient can only very lightly press his fingers / hand to signal what he / she wants. Speaking or eye tracking is not possible.
The person is also not able to ...
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Different battery capacities in series is poor
How is the scientific (electrochemistry, physics, electrical, etc) explanation on different battery capacities in series is bad or poor and will damage them ?
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High-side mosfet switch placement
this is a power circuit I'm trying to complete:
the button at top turns the curcuit on, supplying VCC to mcu, and the MCU will output a high signal to a pin (marked in pink) which turns the N-MOSFET ...
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How can I fool an auto-calibrating capacitive touch sensor?
I have a MicroBot Push - looks like this:
Below the blue ring on the top is a capacitive touch pad and a TTP223-BA6 controller. Here's what it looks like under the hood.
It's a long story, but I ...
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Current limitation to capacitive voltage divider
For an AC capacitive voltage divider, I would think the amount of current that could come from the divider would be limited by the absolute size of the capacitors. The flow of current should be a ...
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Why are parasitic capacitances the main factor for limiting high frequency performance of active devices such as transistors? [closed]
According to the Wikipedia article, the reason for the limit of frequencies in which transistors operate is the parasitic capacitance. But I don't understand why this is so.
Wikipedia article:
...
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Finding the kVA loading after improving the power factor
This is a homework question I've been attempting. But the answer I get doesn't match with whats given and I don't understand why my method is wrong.
This is the question with answers.
Here's what I'...
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Capacitive Touch Faucet Solenoid Battery Box vs AC/DC adapter [closed]
I have a MSTJRY touch kitchen faucet purchased through Amazon. It uses a valve solenoid in line with the water supply to control the on/off of the faucet based on capacitive touch on the faucet stem. ...
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TTP223 capacitive sensor on USB switch takes two presses to work
I'm trying to solder a TTP223 capacitive touch sensor to a USB switch (specifically a "UGREEN USB 3.0 Switch, 2 In 4 Output") to rig a sort of capacitive KVM switch to a desk PC I'm building,...
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How to properly drive parallel analog switches (variable capacitive loads) with opamp(s)?
So as you can see I have 16 SPDT switches on one side of my 16 'RUT paths' and 16 SPDTs on the other side. Each SPDT(ADG1434) has two source pins (SXA and SXB) and a common drain pin (DX), 'X' ...
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How to make sure that my compensated attenuator would work for certain pulse widths?
I have an input (one-shot) pulse that has to be attenuated by 1/2 (half). The input pulse would be of variable width in between 1us and 100ms and would have a variable amplitude: one voltage level ...
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Test device for capacitive touch screens?
Are there any (more or less) simple test devices for capacitive touch screens,
e.g. something which I can attach to a touch screen and which is able to do capacitive inputs at fixed locations (ideally,...
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Reverse-engineer pinout of capacitive touchscreen
I'm interested in reusing the capacitive touchscreen of my old iPad. (As a learning experience -- I'm aware that this project will cost me more than just buying a new capacitive touchscreen would.)
...
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What material to use for a capacitive sensor?
I'm doing a DIY project that I want to use a capacitive sensor for. I'm having a little plastic box and I want to send a wireless message when someone touches the top of it.
I understand all the ...
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Variac and Other dropper in line
I have a beautiful old variac, with a sliding (rotating) center contact.
I would love to use this on a nice LED string inside a glass bulb on top of the device.
But also, use the variac as the dimmer, ...
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