Questions tagged [capacitive]
Based on the usage of capacitors, condensators. Alternatively, utilizing the derivative of signals.
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How to use a capacitive touch screen without a human hand
I'm a programmer, and I usually hang out over on stack overflow, but I have a electricity question.
I'm trying to interact with an APP on my phone by indirectly touching the the screen. Modern ...
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How to make 1 bit permanent memory circuit?
I would like to make a simple circuit to store or save 1 bit of data. The circuit should be able to remember the state of an LED ( on or off ) even if the supply is disconnected from the circuit. I ...
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Triggering a capacitive sensor electronically?
I'm working on a little project I call my "Green Box". Basically, I'm trying to drop my electric usage as low as possible, without losing the convenience of my gadgetry.
So far, I'm incorporating a ...
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Conducting plastic for capacitive touchscreens
As I am disabled I have to use a headstick (see picture below) to do stuff on the computer. I also have a phone with a resistive touchscreen, which works well with my headstick.
But here is the ...
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Electric shock from laptop due to capacitive coupling?
If a person touches an exposed wire (the wire has a ground-prong) on the 20V side of a power cable while barefoot, I heard that it is possible to receive a shock of higher than 20V due to capacitive ...
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Capacitive AC voltage detection
As I understand it, a non-contact voltage tester works by creating a capacitive connection from a power line to ground, via the detection circuit and the operator's hand/body. This connection passes a ...
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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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Digital control over capacitive touch
I would like to generate computer controlled touches on a capacitive touch screen (e.g. iphone) using the following setup: I have a conductive patch (size of finger) that I place on the touchscreen ...
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What exactly does a capacitive touch screen need to register input, and how can that signal be produced?
There are active styli out there, and they take 3A or 4A batteries and don't require any wireless connection. How do those emulate human touch?
EDIT: I am specifically interested in iPad touch ...
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Capacitive Touchscreen for DIY usage?
Anyone know of a good source for capacitive touchscreens in low quantity at a reasonable price? Just something to play around with in projects, I'm interested in either small (eg for portable ...
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Driving LM3886 at 100 KHZ in Bridge Tied Load (BTL) configuration?
Would someone have experience with driving a pair of LM3886 Overture Power Amplifiers in BTL with up to 100 KHz sine wave?
My parameters:
Frequency band of interest: 20KHz to 100 KHz, sine wave
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Causes of ringing in a PCB
Im trying to understand the source of ringing at the termination point of a PCB traces before i delve into actually designing a PCB. For example, by 'termination point', I mean a clock signal ...
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Capacitive touchscreen [duplicate]
I am doing project in which I want to perform read and write operation by using a capacitive touchscreen. What I know is I can trigger capacitive touch screen by:
By using electromagnet as I heard ...
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Water level capacitive probe topology
I'm building a small capacitive water level sensor for a reservoir (16cm tall x 10cm x 7cm).
This prototype gives me 10pF on free air and 20~30pF on medium water levels, so its definetively doable (...
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Can a water drop do a "fake" touch on a capacitive touchscreen?
If a capacitive touchscreen is hit by water drops, like rain, will it report a touch?
I'm trying to evaluate what is the most appropriate touchscreen solution to use in an outdoor kiosk.
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Given a load, how do you calculate whether it is capacitive or inductive?
If the impedance at the load has the form of \$Z = R + jX\$, where \$R\$ and \$X\$ are positive real numbers, then then network is called inductive. If \$Z = R - jX\$, then the network is called ...
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How do you measure soil moisture using a capacitive sensor?
There are a number of capacitive moisture sensor designs on the internet, which use the insulated copper pads on a PCB.For example:
http://zerocharactersleft.blogspot.in/2011/11/pcb-as-capacitive-...
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Inrush current limiter - design questions/review
I am considering to use the inrush current limiting circuit that was suggested in this answer.
I have a pretty big capacitive load of about 40000uF to charge. Its a buffer for a GSM modem that needs ...
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Modelling a "scope probes' acting as an antenna" phenomenon in a circuit
Here below I draw a simplistic model for stray capacitance issue in SMPSs:
Basically pF level Y capacitor across the AC line forms an RC voltage divider when measured by a voltmeter with respect to ...
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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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Simulate capacitive touch
I am using an Arduino Uno and would like to simulate a capacitive tap with zero human contact on my iPhone 5 screen.
What seems to work right now is putting a coin on the screen and connecting the ...
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Transistor selection for 5V LED circuit
I'm having a trouble selecting the proper transistor to switch this LED circuit
simulate this circuit – Schematic created using CircuitLab
The LEDs are 3.6v at 20 mA.
I tried figuring the ...
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Sensing the capacitance value of a material - for an ID system
This is a follow up question to 'How does a Capacitive ID / Signatures / Sensing system work? e.g. Google Bloks'
In the 'Google Bloks' project. A tangible programming experience is created by ...
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Split-phase 230VAC transformerless capacitive power supply for 5V@30mA regulated output -- series cap?
I'm a hobbyist developing a hybrid power switch (electromagnetic + solid state) for a resistive electric stove (8kW max) top. I have a profoundly autistic, disabled adult in the house and I need a ...
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Coax cable - capacitive load
I still have an understanding problem with impedance matched coaxial cable and its behaviour.
We do impedance matching to prevent reflections.
How does my signal source see the whole cable? At a ...
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Capacitive sensor as drop-in replacement for mechanical button
I have a device X (talking toy), which has a jack of two wires for an external button. That is, I can short the two wires and device X accepts it as a press of a button.
Now, I want to use device X ...
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How to make fast (low latency) capacitive touch buttons
I'm looking to create low latency capacitive touch buttons for a musical instrument. The response time (from physical touch to touch registered in microcontroller) needs to be around ~2ms or less.
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What is the minimal capacitor (capitor type/size/capacity) needed to fool a capacitive touch screen? [duplicate]
Say I want to provide a device (completely batteryless of course, and detached from any human touch) the capability to immitate a touch on a capacitive screen (Galaxy S6 here). I know I just need some ...
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Noise due to stray voltages in a data acquisition system
A single ended earth grounded data-acq. board on the left in the below illustration has inputs coupled by BNC cables coming from force transducer amplifiers A1, A2, A3, A4 as shown on the right:
If ...
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How does a Capacitive ID / Signatures / Sensing system work? e.g. Google Bloks
In the 'Google Bloks' project. A tangible programming experience is created by allowing children to place physical instruction blocks next to each other.
The computer is able to read the sequence ...
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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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HF signal in a null experiment. What is the exact mechanism?
Since I've tried to experiment with electronics, I am faced with the problem of HF noise and signals bypassing almost anything I try to stop them. This begun with my attempts to filter the noise of a ...
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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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Loading an Asynchronous Generator
I am doing an experiment that involves loading an asynchronous 50 HZ generator. For the load to consume current it has to be a capacitive load to cause a phase shift between the current and the ...
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High voltage pad buffer design with 2nF load and ringing on first stage output
I am trying to design a high voltage (12V) buffer that will drive a sine wave with rail-to-rail peak-to-peak amplitude and a big capacitive load, maybe 3nF.
Browsing I came upon this Master's project: ...
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Water level: BIG capacitive level sensor with steel bars?
So I want to measure water level under a bridge, or inside the city drain.
Would it be possible to run two long (4 meter) metal probes, each one enclosed inside a PVC pipe, and placed one next to the ...
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ESD protection of capacitive touch doorknob circuit?
This is a follow-up to my question: How can I use a generic doorknob as a capacitive touch sensor?
I am now ready to move beyond the proof-of-concept stage, but I have not yet learned of a ...
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Glitchy Touchscreen Caused by Charger [closed]
I recently bought a Nexus 4. I had a couple of spare chargers laying around. I used a charger that apparently had an issue exactly like: https://www.youtube.com/watch?v=mrpBTG0a6K8. If I used my own ...
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How to safely switch a big inductive load with a Triac using a capacitor snubber?
I am building a Spot Welder with a big powerful transformer.
I have to switch a big inductive load of 70mH (input of a transformer)
The switching will be done with an SSR (Opto Triac Zero crossing SSR-...
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