Questions tagged [capacitive]
Based on the usage of capacitors, condensators. Alternatively, utilizing the derivative of signals.
278 questions
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MOSFET SSR inrush current with capacitive load
I'm searching for a small switch to switch 400 V AC 50 Hz on 11 nF capacitive load. Switch would not be opened and closed often and continuous current would be under 2 mA. 2 resistors were added ...
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resistor placement in inverting amplifier to minimise noise coupling
(Image is my own creation.)
I notice that an inverting amplifier can be very sensitive to capacitive and inductive noise coupling on a PCB. I was wondering whether the placement of the R1 resistor ...
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Circuit To Simulate Capacitive Touch Button Press - Raspberry Pi Zero
I realise similar questions have been asked in the past about automating capacitive touches, but I'm aiming to put this into practise with a simple circuit.
I want to be able to simulate / automate ...
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How can I make an effective head-mounted pointing device for a touchscreen
I have read How can a capacitive touch screen be triggered without human contact? and feel a bit closer to understanding the technology, but I am still a bit puzzled.
I recently picked up the task of ...
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Purpose of electronic elements in a capacitive dropper circuit
I have found a capacitive dropper circuit in an LED light bulb:
I have a few questions about this circuit:
Normally, in capacitive dropper circuits, I would expect a resistor parallel to C1. I am ...
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Sine wave CMOS buffer from inverters with or without feedback
Is it possible to buffer a sine wave using inverters alone or with some kind of feedback?
I've been browsing google for minimalistic (I'm in 3.3-12 V domain) sine wave buffers and this thought stuck ...
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How to simulate a finger touch electrically to remove noise
I am working on a project with "SIM800L" GSM module, the problem is that there is a noise from the module in the calls and it disappears when I touch the module's body with my hand.
Kindly, ...
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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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Current slew rate specification of op-amps?
I know that slew rate specifies how fast the output voltage of an op-amp can change. But is there a measure that specifies how fast the output current of op-amps can change?
I need this information ...
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Vintage capacitive switch
I have this switch from a Philips Electronic 212 turntable. It’s simply two metal pieces, one a ring and the other a button-like center. I’m not sure, but I think it is a capacitive sensor or button.
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Time delay circuit to reverse the rotation of DC motor when input is high
I am trying to design a circuit to use to control a DC motor according to the output of a capacitive proximity detector.
The circuit should turn ON the DC motor in forward direction when the hand ...
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Convert capacitive sensor into physical button?
Is it possible to turn a capacitive button in to a protruding mechanical one?
I am thinking something round that sticks to a surface with a capacitive button on it and is essentially just a button ...
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Looking for a large capacitive touch array controller
I'm building a capacitive touch panel.
It has an odd shape, so I resulted to building my own with the capacitive diamond array solution.
It doesn't have a screen underneath, so it's all contained on a ...
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What is the maximum reasonable cable length for a humidity sensor?
I have an ESP32, and use capacitive soil humidity sensors to check the humidity of my plants. They get shipped with about 15 cm of cable attached.
What is a reasonable/safe cable length I can use ...
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How to design an accurate high tripping voltage capacitor discharge circuit
We have a system which discharges a capacitor (20 uF) charged to approx. 3kV DC using a spark gap. The principle is simple, when the voltage exceeds a certain value, it jumps the gap (around 0.6 mm) ...
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How to remotely control a TT6061A dimmer using an ESP8266 and detect its current state?
I am trying to remotely control a TT6061A (embedded inside an existing module), 3-way dimmer using an ESP8266. My goal is to set the device state to OFF, LOW, MEDIUM, or HIGH.
However, there is no ...
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I want to know if the following circuit is inductive or capacitive. What is the difference between inductive and capacitive?
I want to know if the following circuit is inductive or capacitive? What is the difference between inductive and capacitive?
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Is there a single cycle wave trigger circuit?
Is there a circuit design where if the input is high (at any length of time), the output will only be one cycle at a fix amount of time?
I'm currently working on a capacitive touch switch (I'll use ...
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Does max OP Amp Capacitive Drive Capability Matter with Active Filter?
I know that every OP Amp does have a limited capacitive load drive capability.
Even if not specified, it is always a good practice to use a series isolation resistor.
Anyway; when looking at an active ...
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How to drive 400 nF load with DAC
I need to drive a some kind of pzt transducer with a triangular 6 Vpp voltage. The transducer is modeled as a 400 nF capacitor. I want to drive it with 10 kHz 3-9 V triangular voltage however my DAC ...
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Ultra-fast load switch
I have a question that I am assuming has a very easy answer (hopefully). I am trying to turn on and off the power to a pcb really fast, on the order of 1us. My problem is that my board has some bypass ...
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Differences in capacitive loads
I'm in school and I am trying to figure out a question for homework. It reads as stated:
Version
Voltage
Clock Rate
i.
Version 1
1.75V
1.5 GHz
Version 2
1.2V
2 GHz
ii.
Version 1
1.1V
3 GHz
...
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How to create a clearance area around a single PAD in Altium
I'm creating large circular pads (13.5 mm diameter) for some capacitive buttons on ALTIUM.
I want to create a circular clearance non-copper space area around each of these pads (around 1..2 mm) to ...
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What CAD software is used to design and manufacture projected capacitive touchscreens?
I am looking to learn more about how projected capacitive (PCAP) touchscreens are designed and made, specifically with laser ablation. What kind of CAD software is used to create layered drawings for ...
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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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How do I achieve well-formed pulses in a Dickson charge pump?
A picture is worth a thousand words, and I tend to make a lot of mistakes in my words, so, first picture, the circuit in question:
I know the Dickson charge pump looks a little different but it is ...
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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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How can I use a microcontroller to trigger an existing capacitive-touch pad?
(Note: I have found several other questions on a similar topic, but none of them address my specific issue.)
I have a lamp that is controlled by non-contact touch buttons. The user-facing surface is ...
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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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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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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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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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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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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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Bypass touch sensor IC with a button?
I want to replace a capacitive touch sensor on a circuit board (I think it’s a TTP223) with a tactile switch to overcome over/under sensitivity issues. I have wired a switch to ground and the CMOS ...
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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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Pre-charge resistor and contactor power dissipation calculation
I am building my e-motorcycle. I am planning to use only one contactor instead of using three contactors. In my plan, pre-charge resistor and contactor circuit will be main contactor too. I am curious ...
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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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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 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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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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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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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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