Measuring Electric Fields w/Neon?

In summary, n00bie is trying to measure the electric field strength to confirm that it is at or above a certain point. He is using a neon discharge to do this, but it will change the field strength. He is also trying to use a resistive attenuator to reduce the AC response of the neon discharge.
  • #1
Clyde
3
0
Good day everyone! n00bie here.

I did do a search before I posted this... found a lot of info, most of which I couldn't apply to what I am doing (because I wouldn't know how).

I have something that I am working on that creates an electric field to alter certain chemical compounds. The distance between the two electrodes is around 1.5". I am trying to measure, or at least, get an idea, of what the field strength is inside the electric field (IE: how many v/cm). I don't need an exact measurement, just need to confirm that I am at or above a certain point.

Someone suggested a method using small neon bulbs (I think he said neon). He suggested two wires that would then be placed inside the field. Along with a few other things he would add to this 'meter', would allow the bulb to glow if the field was at a certain strength.

Any ideas on how I can measure the voltage inside this field?

Thanks!
 
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  • #2
What's the voltage between the 2 electrodes?
 
  • #3
Drakkith said:
What's the voltage between the 2 electrodes?

i built a custom power supply that operates up to 2000v RMS. The electrodes are a little over 1.25" apart. 600-900v maybe?

Part of this project is to understand how to apply the electric field so that the v/cm is anywhere from 200 - 800v. Having an impossible time measuring it which is where this thread came from.

I'm no EE, so pardon if I'm using incorrect terminology or phrasing this awkwardly.
 
  • #4
The problem with using a neon discharge to measure the gradient is that it will change the gradient by clamping the electric field. You would need a high impedance sensor to accurately measure the AC electric field.

600VAC to 900VAC. Is it a square or a sinewave? If your supply generates a sinewave then you can use RMS in the computations, otherwise the PP voltage will need to be considered.

Why do you need to measure the electric field strength when it can be computed from the VAC excitation along with plate separation and maybe geometry?
 
  • #5
I was taking the voltage setting and dividing it by the number of centimeters between the plates. It's a sine wave.

I'm going by what my EE told me to do to calculate the v/cm. I have a hard time following him completely sometimes because I don't have an electrical engineer degree.

I want to measure the field to make sure that when I am working my tests, I know for sure the field strength is where it should be. I don't have a sting enough voltmeter to measure it unfortunately, otherwise, I'd do that and just do the math.

Am I missing something? Should I be Approaching this a different way?
 
  • #6
I'll make an assumption that your sine wave is symmetrical about ground, so the plate voltages are always equal magnitude but opposite polarity. Measuring the voltage on one plate relative to ground will give you less than 1kV RMS = +/–1415V peak relative to ground.

Now consider attenuating that +/–1415V with a chain of ten resistors to ground, 100k each with a 100pF, 200V capacitor in parallel. That will give you +/–150V peak AC across the lower resistor with an impedance of less than 100 k. You can measure that with a cheap digital multimeter on the AC voltage range. Multiply the meter RMS by 20 and you have your RMS plate differential voltage

The parallel capacitors make the AC response of the resistive attenuator independent of frequency and less sensitive to cheap meter capacitance.
 

1. How is the electric field strength measured using neon gas?

Neon gas is used in a device called a Geiger counter to measure electric fields. The gas is ionized by the electric field, causing it to emit light. This light is then detected and measured by the Geiger counter to determine the strength of the electric field.

2. What is the range of electric field strength that can be measured with neon?

Neon gas is most sensitive to electric fields in the range of 1,000 to 100,000 volts per meter. However, it can still detect electric fields outside of this range, with some limitations.

3. Can neon gas be used to measure both AC and DC electric fields?

Yes, neon gas can be used to measure both AC and DC electric fields. However, the method of measurement may differ slightly for each type of field.

4. Is neon gas a reliable method for measuring electric fields?

Overall, neon gas is a reliable method for measuring electric fields. However, it may not be as accurate as other measurement techniques, such as using a voltmeter. It also has limitations in certain environments, such as high humidity or extreme temperatures.

5. Are there any safety concerns when measuring electric fields using neon gas?

There are some safety concerns when using neon gas to measure electric fields. The gas itself is not toxic, but it is highly flammable and can pose a fire hazard if not handled properly. Additionally, the electric fields being measured may also pose a safety risk, so caution should be taken when using any type of electric field measuring device.

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