Electronics > Beginners

Measuring voltage (and frequency) of spark

<< < (3/4) > >>

joeqsmith:

--- Quote from: petert on December 20, 2019, 01:27:11 pm ---Hello,

I experimented with a piezo crystal from a lighter to generate a high voltage spark. A coherer was able to detect the generated EM wave (from the spark/spark gap) in close proximity.

Now I am trying to generate a spark with a coil that has the same effect. I charge a coil/inductor with a 4.5V battery and when I break the contact or make it, a spark is generated as expected.

How could I measure the spark voltage (and frequency) between the two leads? I am worried it might damage my scope.

--- End quote ---
Did you made your coherer and can you post a picture of it?   

When I was looking at my piezo crystal lighter,  I was looking at the current rather than the voltage.   To look at the voltage on my ignitions, I normally will use a capacitive coupled divider.   For the lower frequency current, I have a wide band transformer.    I kept one of my first DSOs just for this sort of potentially destructive experimenting.     

T3sl4co1l:

--- Quote from: imo on December 21, 2019, 04:27:41 pm ---I doubt so..
The HV coil generating the sparks and the LC tank (or a resonant antenna) are two different things..
You need a resonating "something" wired/coupled to the spark gap (see above the wiki) in order to produce your "frequency of interest"..

--- End quote ---

Measure some coils, or try it yourself.  Or write it out from E&M theory.  I think you will be pleasantly surprised. :)

Tim

petert:

--- Quote from: tautech on December 20, 2019, 08:45:50 pm ---1000:1 probes for scopes are not that expensive.
Look up Joe Q Smith's DMM test videos where he uses grill ignitors and builds a 1000:1 probe so to see and measure the waveforms.

--- End quote ---
I suppose you mean this video?


Other possibly relevant videos:




Interesting but not directly related:

tautech:

--- Quote from: petert on December 22, 2019, 09:01:46 am ---
--- Quote from: tautech on December 20, 2019, 08:45:50 pm ---1000:1 probes for scopes are not that expensive.
Look up Joe Q Smith's DMM test videos where he uses grill ignitors and builds a 1000:1 probe so to see and measure the waveforms.

--- End quote ---
I suppose you mean this video?

--- End quote ---
:-+
Yep, all those !

We can see from Joe's investigations that grill ignitor voltages aren't that high and a 1000:1 probe capable of handling 15kV should be ample to view their waveforms safely.
See if you can find any Pintek HV probes sold locally:
http://www.pintek.com.tw/files/pintek/HVP-provided-Fig.pdf

petert:

--- Quote from: joeqsmith on December 21, 2019, 05:06:19 pm ---Did you made your coherer and can you post a picture of it?   

--- End quote ---
It's not the clearest, because I used it several times already and the flexible tube has become a bit tarnished.
I also adjusted it several times (moving the screws to adjust the distance) until I found a working "configuration", tapped it to decohere it, so that some of the filings are "spread out" on the screw threads.
The filings are of Cupronickel, a mix of copper and nickel (75 % Cu, 25 % Ni).

Full resolution pic (click to zoom):

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod