Questions tagged [electrostatic]

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1answer
85 views

How it is determined whether an equal sign can be used within the boundaries?

Why equal signs weren't used for limits(r < a, a < r < b, r > b instead of r <= a, a <= r <= b, r >= b)? Two concentric spherical surfaces of radius a and b = 2a are in vacuum ...
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3answers
122 views

Can an electrostatic voltage be divided with very large resistors?

Is it possible to divide an electrostatic voltage from a Van de Graff generator or electrostatic generator with very large resistors?
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1answer
36 views

Charge transfer in conductors of different metals by touching

when we touch two metallic conductors one is neutral and other has excess of charges, Case 1- Both metals are of copper, then we can calculate actual charges on them at steady state by capacitance ...
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2answers
50 views

Static Electricity - and charges

When we comb our hair (with a plastic comb) and then bring the comb close to bits of paper, the bits get attracted to the comb. I understand this is because the comb is now electrically charged. Why ...
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1answer
31 views

Voltage boosting device for electrostatic experiment

I want to get 2kV to 6kV (adjustable) for performing electrostatic experiments with parallel plates. What device can produce such high voltages from the 230V mains? I watched a video on YouTube ...
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0answers
33 views

Electrostatic protection - input and output ESD protection added to op amp w/built-in ESD

I have an op amp circuit using the OPA2626 that has a built-in input/output ESD protection of +/-3000V human body model. The circuit is 3.3V single supply, non-inverting, with only an external ...
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0answers
42 views

What is considered ESD Sensitive and non-ESD Sensitive?

For example, if an integrated circuit has an HBM rating of 8 kV but is now embedded in a circuit board, which is now installed inside an equipment assembly, I would think the ESD susceptibility of the ...
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1answer
125 views

Harrington rod from spinal fusion might be acting like a human EMF antenna [closed]

In 1994, I had a spinal fusion surgery to correct Scoliosis which was a result of my medical condition, Spinal Muscular Atrophy Type II. I've used a wheelchair my entire life. Because my upper body ...
1
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1answer
43 views

Energy subtracted from a capacitor for a given voltage drop

I am trying to estimate, from a total energy of a capacitor (which is the output of a charge pump circuitry), how much energy do I have to power up an LED before the voltage goes below a certain ...
0
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1answer
49 views

ESD strap/mat when working on battery powered devices/PCBs

When the devices you're working on are plugged in an outlet or when you're working on loose components, it makes perfectly sense to ground yourself to the outlet or any other solid ground through a ...
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0answers
30 views

Electrostatically charging a capacitor with varying amounts of charge

I'm working on a project that will measure charge, in the nanocoulomb range, of some device powered by some DC power. I'm planning on using a capacitor, a 1 nF, as a means of measuring this charge. ...
0
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1answer
30 views

Voltages and charges with regard to ESD

My question is with reference to this question - ESD protection using a capacitor I am unable to grasp the relation between charge, voltage, and capacitance, although I can understand all these terms ...
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1answer
52 views

Protection against electrostatic paint by draining the charge

I have a circuit for an automotive sensor aimed for 24V supply. The circuit itself is well tested for EMC requirements including power line transients and EMC immunity. Usually the requirement is for ...
0
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1answer
49 views

When grounding conductors in electrostatic problems, is the reference point of electric potential defined at infinity or the ground?

I am confused about the meaning of 'grounding' in electrostatics. My textbook claims that any grounded conductor has zero electric potential, but it seems to me this claim can have two different ...
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0answers
34 views

Capacitance calculation of comb-drive actuator

I just want to make sure that I am performing this calculation correctly... From this COMSOL study, I gathered the following info... $$C_t = N\frac{\varepsilon_o\varepsilon_rl_ot}{d}$$ $$C_f = \...
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0answers
215 views

What is causing this weird effect with aluminum?

I grabbed an LED and then scraped an aluminum plate with a pin, and it turned on at some points, at first I thought it was electrified but it wasn't, then I tried with another aluminum plate and it ...
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2answers
34 views

Energising Electrostatic Charge Into Nylon Ribbons? Is it possible?

Forgive me for how high level this is but this is the goal I'm trying to achieve here: I want to build a device that has dangling ribbons of a material (lets say nylon for now) that can be actuated ...
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3answers
251 views

Is it safe to use hot glue in electronics?

I know question seems too basic to ask but I couldn't find any specific information anywhere . I want to use hot glue gun to stick components and cables into cardboard to prevent them move or break ...
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1answer
80 views

MOSFET Triggers with Electrostatic Energy

In the attached circuit with a 5V relay and a 30V load across it, I've noticed the FQP30N06L MOSFET triggers with even electrostatic energy (touching the gate). The difference between the circuit ...
0
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1answer
18 views

How do I measure material specific(volumentric) capacitance

I'd like to test electric capacitance of different powders pressed into solids. I want to know if my procedure is correct. First I connect a wire between the material and a ground (ex. radiator) to ...
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1answer
87 views

Gauss' law for two point charges?

When we model electric field as something that represents the "flow" of something that is conserved, we can prove that the flux due to a single point charge, through the following surface, Flux ...
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2answers
95 views

What is the energy density of voltaic piles?

I heard voltaic piles have very small power but long lifetimes so I was wondering what their energy density per unit volume and energy density per unit mass is. If specifying a type of voltaic pile ...
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2answers
62 views

How I can simply measure interwinding capacitance in a transformer with electrostatic shield

I want to measure which is the effect of the connection of the electrostatic shield (between primary and secondary) to ground (or to neutral) in reducing the interwinding capacitance in my transformer....
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1answer
80 views

Switching 1875 Volts through a relay

I am trying to create an electroadhesive device that I can switch on and off easily, however, after using one relay that worked beautifully to do this function, I went out and bought a 4 channel relay ...
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0answers
62 views

A conductive ball connected to a capacitor

I am not asking for a task solution, but rather how to solve a problem. Say I have a ball of radius R, charged to a voltage of U (relative to the ground). I also have a flat capacitor with a side ...
0
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1answer
125 views

Soldering Iron and Electrostatic Bracelet Connection

I have a DIY soldering station and I want to ground the soldering iron and I also want to use a electrostatic bracelet connector for the soldering station. Can you please help me how to connect the ...
1
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2answers
49 views

Something wrong with open USB circuit, electrostatic problem

I faced a strange problem with the following circuit. I'm using some buck converters and an Arduino. The buck converter (Vout = 5.25v) is for a USB charger (up to 2 Amps). Well, I think the circuit ...
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2answers
175 views

ESD problem on water tank?

We have a water level monitor attached to a water tank. The water monitor has an hydro-static (output 0-5V) water sensor that goes to the bottom of the the tank. (See figure) In most cases this works ...
1
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1answer
319 views

How to convert high voltage DC at low amps to low voltage DC or AC at high amps?

How to convert high voltage 500 volts DC at very low amps to lower voltage 12 volt DC or AC at high amps? Must I use an electrostatic motor or can I use an op amp? The reason I am posing this is a ...
2
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1answer
138 views

How to extract energy from an alternating electric field?

Given an alternating electric field E inside e.g. a big parallel plates capacitor, how can you make use of the field's energy to power an electronic device? So far I thought of putting two smaller ...
3
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0answers
67 views

System of multiple conductors: image method

The problem statement, all variables and given/known data The following figure represents the traversal cut of a system with two cylindrical equal conductors of radius r0 length l at a distance d ...
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1answer
118 views

How is this copper showpiece making static electricity

I'm trying to make a showpiece which generate static electricity just like in this YouTube video LINK Does it have Tesla Coil (Slayer Exciter) inside it or Negative Ion Generator?
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1answer
125 views

Insulating from static electricity

I am happy to announce that my pocket extra-strong static electricity generator project is now complete and works well. However there is one problem, I am often getting zapped severely (to the extent ...
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2answers
169 views

What's the current leak path of the electrostatic discharge during an EMC test?

When we develop a new product we need to pass the EMC test,I really wonder what's the current path during a electrostatic discharge test. Here is the test situation: Q1: If the EUT(equipment under ...
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4answers
2k views

Why no macroscopic electrostatic electromechanical parts?

So, I understand that relays, motors, and other electromechanical devices are almost always electromagnetic devices. Why is this? I know that electrostatic motors exist, but what makes them ...
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2answers
176 views

Energy lost in Capacitors [duplicate]

Suppose there are two identical capacitors of capacitance C and one of them is charged to a potential V and gets a charge q. The energy stored in this capacitor is \$1/2cv^2\$ or \$q^2/2c\$ . Now this ...
3
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2answers
379 views

How should I use a static-shielding bag prior to opening, and why?

After grounding the ESD mat and wearing the properly grounded anti-static wrist strap, what is the correct process to take the contents out of the static-shielding bag and take it onto the antistatic ...
0
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1answer
204 views

What is a safe way to carry around (wrt ESD safety) a single-board computer in an enclosure like this? [closed]

I have a single-board computer and an enclosure, which will hopefully look like this in the end: I have three small questions: If I only hold it from the edges while assembling the enclosure, do I ...
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1answer
78 views

why dont we just use ion wind flowing through evacuated pipes?

Why dont we just use ion wind flowing through evacuated pipes? I ask this because if we reduced the atmospheric pressure in the pipes somewhat, and made them out of a cheap yet durable insulating ...
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2answers
182 views

Accurate explanation of diode reverse bias mechanism

For quite some time I haven't been able to convince myself how reverse bias works using conventional explanations that involve words like 'minority carriers', 'majority carriers' etc. which do not ...
0
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1answer
101 views

Electrostatic in an Arcade Machine (Arduino)

I set up an arcade machine, which consists of an Arduino, a coin validator, a 12 V adapter, and a PC. It works as expected, when I insert a coin, a signal is captured via Arduino. The output normally ...
0
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1answer
88 views

Bar connecting leyden jars on wimshurst machine

So I finally finished building my wimshurst machine! Disks are around 14" and it works, but the sparks get about 1/2" :( so i was wondering what i could fix and for my metal thats connecting the ...
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2answers
86 views

Can I use a threaded rod on a wimshurst machine

On my Wimshurst machine which is built similar but not the same as http://steampunkworkshop.com/how-build-wimshurst-influence-machine-part-1, I'm using a threaded rod that comes out of the Leyden jar ...
0
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1answer
394 views

Motion of an electron in a uniform electric field

An electron moves from negatively charged to positively charged terminal of a battery. When it does so, its electric potential energy decreases i.e it moves from high to low electric potential. But it ...
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3answers
273 views

electrostatic and capacitors… more about the capacitor though

done some reading, got me thinking. done some researching got me doubting... but my question is. is there a capacitor that doesn't degrade and doesn't lose capacitance over time? from all of my ...
3
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1answer
115 views

Protecting digital electronics from nearby high voltage sparks

I am controlling a high voltage power supply to generate corona discharge. To switch it on and off I am using an AC relay controlled by a microcontroller as shown in the figure. The controller ...
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0answers
38 views

Charge distribution/movement in an insulator

The way I understand it, net charge in a conductor spreads out evenly over the surface, while for a charged insulating object, the charge will tend to stay clustered around the spot where it was ...
0
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1answer
73 views

Determine the position of the charge for equilibrium

Question: A system of three electric charges lying in a straight line is in equilibrium.Two of the charges are positive with magnitude Q and 2Q,and are 50 cm apart.Determine the sign,magnitude and ...
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1answer
91 views

Need help with exam problem [closed]

Can somebody please help me with this task: Two equally large (r = 5 cm) volume charged non-conductive spheres are fixed so that their centers are a = 1 m away. In the middle of the centerline ...
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0answers
49 views

Point charge between parallel plates

Let's say we have 2 grounded parallel plates and we place a charge Q between them. I'm studying Green's reciprocity theorem and in using it the author states that the charge induced on the plates ...