Discharge Definition and 256 Threads

I noticed high frequency (greater than 800khz) corona tends to orientate vertically as if it were a flame with a strong air blower beneath it regardless of electrode positioning. This is not the case for DC and low frequency AC corona. Is there a reason why high frequency corona orientates...

How work triboelectricity in QFT? Materialists exchange electrons as well as in classical theory?

Hello all. I am conducting a simple research project, and am having a little trouble with the math for paschen's law. my question is. At 74762 Microns of pressure, using pure Neon gas, what is the electrode spacing in mm for the minimum breakdown voltage of that gas? Thank you.

I previously posted the below as a footnote on one my posts on the Mechanical Engineering Forum and it was suggested I start this thread on the subject here. "PS On a general note about battery replacements. On my field GPS I use rechargeable batteries and always test them before recharging...

Hello. Say I have a high powered device that draws continuous 18A. 3.7v And I have one 3.7v 3500mah 18650 with a maximum continuous discharge of 10A, I know the battery will overheat and will most likely get damaged or shorten its life, or even catch fire. But If I have another battery (same...

Why cathode rays which consist of electron that do not have any colour are seen as a colourful ray of light in a discharge tube??

Homework Statement I have to rearrange the equation V=lnVo -t/RC to calculate C. The gradient from graph = -1/RC Homework EquationsThe Attempt at a Solution I got R/C=ln(Vo-V)/t but the answer I get is wrong

A couple of months ago I was troubleshooting a blown fuse on a power factor correction capacitor in a 4160v motor starter. While I was working through it I noticed that my DMM (fluke 289) would charge the capacitor to a certain degree while on the Ω function. The current from the meter would...

Hi PF According to IEC 60885-2 and IEC 60270 the acceptance criteria in partial discharge (PD) measurements on high voltage cable insulation state that PD level should be below (< 5 pC). The insulation material that is refereed to is often XLPE which is a sensitive insulation to PD. Other...

Hi all, I think this issue periodically resurfaces in PF. I have found a similar discussion in this closed post and possibly others. I'm posting this because I'd like to check my understanding, if anyone is available to provide some furtherinsight. So I'm trying to gather a "overall"...

I am having trouble in making a power source for the DBD. I can't seem to find any calculations to get the required voltage and frequency of AC to generate plasma. I want to know the circuit/method/equipment needed to generate that voltage from a normal 220 V/50 Hz AC socket in my lab.I am doing...

Consider a closed system (central heating). Before the pump is started the static pressure is 2.0 bars. Say the system head loss is 0.6 bars. When the pump starts, will the suction side pressure and the discharge pressure each read half the total head loss (1.7 and 2.3 bars)? Or will the head...

Hallo all, I'm investigating in using a dieletric barrier discharge for gas treatment, if I have two electrodes isolated by dieletric and the discharge gap between both of them has AIR.. how the ionization of air will take place, from where the source of electron which is going to start the...

I am reading about gas discharge tubes and can't work out the types of energy and energy conversion that occurs in a gas discharge tube. Initially before the tube is switched on you have an inert gas with kinetic energy. As soon as the tube is switched on there is an an electric field between...

One of my transistor has failed I tried replacing but sticking any transistor in there does not seem to work. Someone from that worked for Heathkit told just look up number this would work except I can not find cross for 230-616. When this unit worked it always put a little wine out I think it...

Homework Statement How long does it take in time constants ( = RC) for the charge on the capacitor in the circuit shown below to reach one quarter its initial value? Homework Equations C=Q/V time constant=RC Vc = Vo * (e)^(-t/RC) The Attempt at a Solution From C=Q/V I get Q=VC so for the...

I'm trying to understand the difference between these two when it comes to measuring the amount of time they take. As of right now, my current understanding is that pole relaxation is based on the amount of time that it takes for polarization of the charges to go back to its relaxed state. For...

A 2 stage compressor has a final delivery/discharge pressure of 250 bar. hydrogen is been compressed and stored in vessels. The pressure in the storage vessel reaches the delivery pressure(i.e.250 bar) and the compressor is still running ( vessel has a safety pressure of 450 bar) and the...

I know that planes have static dischargers (static wicks) on the trailing edges of wings to discharge static electricity when they are flying. I was wondering how a plane, let's say with electrically resistive fibreglass wings, would discharge this without having sparks ignite while it's...

Hi all, I have a question about the effect of partially closing a pump discharge valve on the system curve, wondering if you guys can help me out. Right now I have the yellow pump curve and the orange 2 inch system curve , producing around 120 gpm against around 110 ft of head. If I expand...

It is known that increased humidity helps discharge a charged body. I was wondering what is the molecular mechanism of that process. It is not clear to me why increased number of well separated uncharged water molecules in the air will help the process of discharge. Does the polarity of water...

Homework Statement After a long time, an inductor is disconnected quickly from the battery and then attatched to a resistor. Homework Equations V = Ldi/dt V = ir The Attempt at a Solution KVL: voltage across inductor - voltage across resistor = 0 Ldi/dt - ir = 0 di/i = rdt/L ln|i| from i(t)...

In the derivation of discharging RC circuit, you use I = -dq/dt to get Q = Q0 e-t/RC But isn't dq/dt already implied to be negative, since charge on the capacitor is decreasing, and you force it to be negative using initial nd final conditions? So the final state is some low charge q, and the...

I am working on a project which involves rechargeable batteries. To calculate the variations in the internal resistance of the battery, i used data from the existing experimental results to establish an approximate value for the internal resistance as a function of the SOC, discharge time and...

In the following video: I understand how the Faraday Cage works, but what has me confused is the arching. If charge is building up on the sphere and then arching over to the cage, where then is that charge sunk to? You would think it would stop arching when there was sufficient charge on the...

Could someone please explain to me what is the definition of a pulse current discharge, and what do we mean by pulse current discharge test ?

Let's say a switch causes a capacitor to charge and the switch opening causes the capacitor to discharge from its positive plate through a common ground to its negative plate. This common ground is connected to other components, if there is a difference in potential in other components to the...

How does the velocity at an elemental height h equates to √(2gh)? My application of Bernoulli's equation is not yielding the result. Please show the process. Thank you

What is relationship between discharge coefficient and minor loss coefficient. Am I right with that equations? hl – minor head loss k – minor loss coefficient ρ – air density A – pipe cross section area Cd – discharge coefficient Δp – pressure drop u – air velocity m – mass flow here is...

This is my first post and am curious if anybody here has any experience or advice on how to discharge a capacitor bank with 6 1F capacitors connected in parallel. I built a electric hybrid (basically electric transmission) vehicle that uses a 31hp gas engine to power a 23kW (peak) DC generator...

I found a thyratron tube at a yard sale recently and I want to build a circuit to heat the filament and illuminate the mercury vapor for purposes of building a novelty lamp. The filament is just 2.5VDC at 7 amps and I have a transformer for that. To light the vapor I will apply DC rectified...

Please delete if not allowed. The teacher charged a 1 square foot sheet of mylar sheet up to approx DC 20 kv one day long ago in school via an modified EHT output of a TV. I had one of my mates hold it by the corners in line with my hands, I then judged and guessed and clapped it with both...

We kept getting some voltage spikes back into our amplifier. One of the things we put in place is a 10kOhm resistor (discharge load) connected to the output of the amplifier. However, the resistor keeps burning and setting on fire. The amp company offered a way on checking this... I'm really...

Hello, I would like to design a spark ignition system with a wider range of energy delivery than a typical MSD system. On the MSD systems I have looked at, they are limited to about a 10 mJ range, but I need to go from, say 5 mJ to 1 J if possible. Does anyone know of a packaged system like...

Hi. If a plate capacitor is charged with some charge ##Q##, then there's a voltage ##U=Q/C## between the plates. The electric field between the plates is ##E=U/d##. Voltage is path independent, if I connect the plates with a cable of length ##l\gg d## the voltage across the cable is the same...

Hi guys! For a school experiment we are supposed to connect a 9v battery to a 180 ohm resistor and multimeter and calculate how long it take to die at different temperatures . does anyone know how can i do this using a formula? I will need it in my report. Thanks for the help! :)

is there any way to fully neutralize a charged metal plate ? connecting it to metal body of relatively huge capacitance will make its charge negligible but not zero? is there any other way?

Hi. Assume we connect both plates of a capacitor to ground and disconnect again, leaving them at ground potential. Then we bring electrons from one plate to the other, until there is a voltage difference ##\Delta U## between the plates. Compared to ground, one plate has the potential...

I'm trying to find a formula for the current flowing through a wire that is only undergoing corona discharge into air. The wire is connected to a charged sphere, which provides the voltage. So far, I've just found formulas for certain ionization coefficients and electric fields, but no current...

Hi guys! I am currently having Physics Internal Assessment in my school and I want to do an experiment to calculate the different times it takes for a 9V cell to to discharge (reach a 0.1V) in different temperatures. The problem I am having right now is to efficiently discharge my cell. How can...

Homework Statement A tank contains oil with a specific gravity of 0.80, which is discharged through a 30mm diameter pipe at 12m/s. Calculate the discharge in L/s and Kg/s. Homework Equations specific gravity=density of oil/density of water mass flow rate=volume flow rate*density volume flow...

Homework Statement I know that when the fluid flow from pipe to reservoir, the coefficient of discahrge is 1, where head loss =k(v^2)/2g... How about the fluid is discharged from pipe to atmosphere?? Homework EquationsThe Attempt at a Solution

Homework Statement So as I understand, a negative Corona discharge happens between an electrode/pin/rod and a plane electrode. When the sharper electrode is connected to the negative (DC) plug, electrons concentrate on the tip, when sufficient breakthrough voltage is achieved a discharge...

I have a problem with Discharge Coefficient of Valve equation which is described in book 'advanced water distribution modeling and management' let me say: I think the expression V^2 in Discharge Equation (P. 618 of the book mentioned) is extra and the equation must be changed to: I)...

When an atom makes a single photon transition it adds a single photon to the radiation field. One might then expect that a low pressure gas discharge would emit photons in Fock states? How is it that photon of an atomic spectral line produced in a low pressure gas discharge become thermalized?

Homework Statement in the notes , author said that the velocity within it is negligible? does the author mean the water velocity in the tank ? so the velocity (v^2)/2g in the 4.24 means the velocity in the pipe ? Homework EquationsThe Attempt at a Solution

I would like to understand how the Euler constant elevated to fractional exponent gave this result? 958mV someone please!?

Homework Statement Explain why a capacitor will discharge, although very slowly when there is high internal resistance? Homework Equations V=IR Q=V/C The Attempt at a Solution I am confused slightly by internal resistnace. Does that refer to regular resistance. From that high internal...

Homework Statement An engineer is planning for a network of pipes to a residential tower containing 360 apartments each one of them consumes 0.05 liters/s of water what is the least possible pipe discharge for the main pipe in the network if the fastest speed of discharge in the pipe is 4m/s...

Homework Statement why the author consider the coefficient of discharge as the z here ? what is exactly coefficient of discharge? Homework EquationsThe Attempt at a Solution