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Questions tagged [capacitive]

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3
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1answer
46 views

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....
1
vote
0answers
63 views

Does a Microcontroller act as a Capacitive load or resistive?

I'm designing a unity gain buffer (IC MCP6002) and in the datasheet, it says that a small series resistor is required at the output, if the load is capacitive and is >100pF. The input of the buffer ...
2
votes
3answers
186 views

Why is this camping light deadly?

I am learning, so go easy on me, if you can. In a video with BigClive, he takes apart a camping light and says it's deadly when you have mains plugged in and usb plugged in at the same time. In that ...
1
vote
1answer
46 views

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 ...
0
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0answers
33 views

Is it possible to drive a capacitive touch screen work as a touch simulator? [duplicate]

I want to simulate a finger touch/move/etc. on capactive touch screen. Obviously using a robot arm and stylus pen is a solution, but it was expansive and the structure was too complex. It would be ...
0
votes
1answer
36 views

Capacitive touch screens and TPU

I'm sorry, I may be slightly out of topic. I'm just an occasionnal "handyman" and I did not found any helping ressource on the web. I'm willing to protect a touch screen and none of the usual offers ...
3
votes
2answers
93 views

Can transformerless power supplies be UL/CSA certified and is there any specific standard they must meet?

I am trying to bias a linear optocoupler on the AC mains side of a circuit, in order to transfer analog information to the secondary side of the circuit. I have designed the following capacitive power ...
2
votes
1answer
108 views

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 ...
0
votes
0answers
18 views

Creating footprint in Eagle library: Connect pads with wire

I'm creating a library with a footprint of a capacitive switch/button. I created two pads for the switch. Now I want to connect the wires of the switch to the pads to not generate any errors anymore. ...
0
votes
0answers
61 views

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-...
1
vote
1answer
39 views

Real world objects touching reading the same capacitance?

In my project, I am developing a capacitive sensor based system which attempts to identify if two real world objects(*) get in contact with each other. I have done my homework (some) on Capacitive ...
0
votes
2answers
84 views

High pass filter is not resulting as good as the scope's AC coupling

I'm generating sine waves by using a micro-controller and DDS module. The output sine normally swings always positive between 0 to around 1V. But I want to generate a real alternating sine with ...
0
votes
1answer
60 views

Can I make a hole in a touch screen without ruining it?

I need to make a big capacitive touch screen with holes inside it, can this be done without ruining the whole screen? Thanks in advance.
0
votes
1answer
36 views

How does capacitive sensing relate to the resistance of the object entering the magnetic field? [closed]

Example: Setting up a capacitive area and dropping resistors of different sizes into the field, how do they affect the field differently? Are several resistors accumulative? Would i be able to tell ...
-2
votes
2answers
59 views

What touch circuit or sensor to use inside a concrete lamp?

Hi I was planning to build a capacitive touch circuit to control a concrete lamp. Will the touch work through 8mm thick concrete slab. If yes please suggest best way. Thanks in advance.
0
votes
1answer
51 views

PIC16F1827 Capacitive Touch Sensor not Incrementing Timer?

So I have a PIC16F1827 on a breadboard and was trying to get a simple demo working where I touch a wire to turn on an LED using the Capacitive Sensing Module. I was primarily going off this example I ...
0
votes
1answer
29 views

variation of thickness of dielectric layer for different textile-based capacitive pressure sensors

For my thesis I am working with textile-based capacitive pressure sensors and I am struggling to see how much variation in thickness of the dielectric layer you can have before you have noticeable ...
0
votes
1answer
48 views

Capacitive coupling: how to collect 60uA from this set-up?

I need to collect at least 60uA via capacitive coupling between a high tension Cu cable with PVC insulation and a connector that is acting as the opposite face of the capacitor (can be a copper plate ...
3
votes
2answers
251 views

Capacitive dropper failure

I have some fridge led light based on basic capacitive dropper. If I connect circuit to AC mains nothing happens. At first I checked all components for mechanical damage and than measured them out of ...
0
votes
1answer
87 views

powersupply ac to ac

I have recently bought a dcp917S and hoped I finally found a wireless chime that I can tie into my apartment buildings bell system. Since I live for rent there I can't do any changes that are not ...
5
votes
2answers
253 views

Help understanding/selecting SMPS to drive capacitive load

I recently bought several SMPS buck converter supplies for a project. They all had about the same specs, typically 90-270VAC input, 12VDC output. Having an expected worst case continuous load of about ...
0
votes
2answers
54 views

Suggestions on conductive materials for textile capacitive pressure sensors

I am doing preliminary research for my thesis. The thesis involves textile capacitive pressure sensors. I am trying to find out more about how the type of conductive material used affects the ...
1
vote
0answers
321 views

Raw data acquisition from a capacitive touch screen

I'm trying to integrate an existing PCAP touch screen into an experimental project I'm working on. For it to work the way I want, I need access to the raw data from the touch-screen nodes instead of ...
0
votes
1answer
213 views

Increase Measurement Distance of a Capacitive Proximity Sensor - Arduino Project

So I am working on a project that I found online at (https://makezine.com/projects/a-touchless-3d-tracking-interface/). However, instead of using my hand to track, I want to track an aluminum ball ...
1
vote
1answer
179 views

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 ...
1
vote
1answer
66 views

Using capacitive touch switch as guitar pick-up selector

I want to use two Schurter 3-101-401 one for each pick up. I was able to get them wired up but the signal for the pick-ups comes out no matter what. Here is the info https://www.mouser.com/...
1
vote
0answers
137 views

Finding the equivelent capacitance of the circuit

Finding the equivelent capacitance of: simulate this circuit – Schematic created using CircuitLab I think that it should be: $$\frac{1}{\frac{1}{C_1}+\frac{1}{C_2}}+\frac{1}{\frac{1}{C_3}+\...
1
vote
3answers
487 views

Shock from Capacitive Coupling

In an AC supply which is not earth grounded, I see a small amount of current flowing to ground from both wires of the supply (live wire has higher) even though the circuit is incomplete. It is due ...
0
votes
0answers
69 views

Using a straw filled with electrolyte as stylus?

Now what I understand is our human body or a stylus disturbs the electrostatic field of a capacitive screen and thus the mobile calculates the disturbance and does some math and registers a touch. ...
2
votes
1answer
141 views

How do capacitive screens work with rubber head stylus?

Now I kind off know that Capacitive Screens have like capacitors built into them that create an electrostatic field. Now whenever a thing that can carry charge or a conductor touches it distorts the ...
1
vote
2answers
583 views

What is the best oscillator to be used in a capacitive soil moisture sensor?

I am working on this project where I am going to make a soil moisture sensor. The principal that I'm going to use is the change of capacitance of the soil with moisture. What I'm going to do is make a ...
2
votes
1answer
359 views

How can I build a touchpad/trackpad?

Every laptop has one - a touchpad/trackpad - for controlling the mouse. I'd like to build my own, external one. I've looked around and I cannot find a tutorial. I have come across 1 example where a ...
0
votes
1answer
79 views

capacitive power supply design query

I was trying to make an LED lamp with 16 series 3528 SMD LED chips. I am planning to use a transformerless capacitive power supply to step down 230V. As per my calculation 16 led will require the ...
0
votes
1answer
229 views

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 ...
0
votes
2answers
398 views

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 ...
-2
votes
1answer
534 views

capacitive touch buttons through VERY thick glass or macrolon? [closed]

for a science-project I need to create 4-5 capacitive touch buttons through thick glass or macrolon. I think we talk about 15cm atleast, if not 20. I wonder if a big coil or big sheet of tinfoil would ...
2
votes
1answer
84 views

AT42QT2160 capacitive touch controller inverted Cs voltage - no touch detected

I'm trying to make my own development board for the AT42QT2160 Touch controller, since the original one was discontinued. I've designed the PCB with 8 buttons and a slider consisting of 8 sections. It'...
1
vote
1answer
99 views

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 ...
0
votes
1answer
346 views

2D DIY capacitive panel

I'm planning on replacing lights with smart bulbs (e.g. Yeelight RGBW) and replacing light switches with capacitive panels connected to Arduinos which will send data to RPi, which will then control ...
1
vote
3answers
122 views

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 ...
0
votes
0answers
125 views

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 ...
0
votes
1answer
318 views

Wiring RGB Vandal Switch as PC Power Button

I'm trying to wire up a Schurter CPS16 capacitive, multicolour (RGB), anti-vandal switch to my PC for use as a power button. The switch function is momentary and normally-open. Tech Sheet I'm just ...
0
votes
0answers
142 views

Reliable way of measuring mains voltage by capacitive coupling with oscilloscope

The question is not about any precise measurements, just for the lack of a better title. Trying to model what one of those non-contact voltage detectors would see when brought closer to a live wire. ...
1
vote
1answer
228 views

AC mains wire finder + live wire equivalent circuit [duplicate]

I'm talking about devices for tracing hidden AC mains wires in walls like this one: https://www.ebay.com/itm/3-in-1-LCD-Wall-Detector-Stud-Center-Finder-AC-Live-Wire-Metal-Detector-Scanner-/...
-1
votes
2answers
410 views

What is the chip used in CJMCU 0401 Capacitive Touch sensor?

I'm trying to make my own PCB with touch keys. I've used the CJMCU 0401 capacitive touch sensor module and now I want to use it in my project. On the chip that is used in this module, there is only a ...
2
votes
1answer
297 views

Using a TPP223 capacitive board instead of a mechanical button

I have this CSR8645 bluetooth module and I wanted to use TPP223 capacitive buttons for its inputs - vol+, vol-, next, prev, etc., but I am wondering if it will work at all. The CSR8645 is originally ...
1
vote
0answers
116 views

Identifying a component and its purpose in capacitive touch circuit

I got a chance to tear apart a touch sensor that comes from some chinese vendor. I was able to figure out the touch controller IC and find a datasheet for it. Datasheet of touch IC However, the pcb ...
0
votes
3answers
183 views

capacitive reactance in a stranded wire

Can a stranded wire exhibit a capacitive reactance? I measured the real and imaginary part of a piece stranded wire using an old LRC meter( HP 4284a). Applied an open loop and a closed loop ...
1
vote
1answer
160 views

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 ...
1
vote
2answers
1k views

ATtiny13a capacitive power supply

I would like to power my Attiny13a MCU with a transformerless capacitive power supply. The MCU itself needs only a few milli amps and it will drive 2 LEDs at 15mA each through it's digital pins. So I ...