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EMP BOX - TEST RESULTS - CALCULATOR AND LED CONNECTED TO A COIL...

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LAN_403

Slava

Thu Nov 12 2015, 07:34PM

Registered Member #518 Joined: Tue Feb 13 2007, 05:20AM
Location: New York
Posts: 168

I dont have a scope. .. can you try it?

I wish i could test for capacitor value too, but that would requre too many experiments.

Signification

Thu Nov 12 2015, 08:01PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

I was a bit brief. What really needs to be measured is the frequency of the LC circuit. It can either be calculated--not very accurate in the real world, OR the time between zero-crossings measured and frequency derived from that: f=1/t.

Slava

Thu Nov 12 2015, 09:08PM

Registered Member #518 Joined: Tue Feb 13 2007, 05:20AM
Location: New York
Posts: 168

With a 10 turn coil, i got 12mH inductance, capacitor is about 1800pF ...

~35kHz

Found some flaws in my experiment...

1) It was hard to tell when the LED turned off

2) I used alligator clips that had long wires, this will throw off the data when working with low turn number of coil...

!UPDATE!

I remeasured everything using direct wire connections instead of alligator clips...

008

Signification

Sat Nov 14 2015, 04:57PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

Did you get the 35kHz by measurement or calculation? Also did this resonant value vary when you changed your measurement connections?

Slava

Sat Nov 14 2015, 05:24PM

Registered Member #518 Joined: Tue Feb 13 2007, 05:20AM
Location: New York
Posts: 168

I used a online calculator to find resonance... How can I optimize capacitance too? I used a value that someone on youtube used... Each capacitor value will require about 40 experiments to get data

...

hen918

Sat Nov 14 2015, 10:51PM

Registered Member #11591 Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556

I don't think there is any way that coil could be 12mH.
12uH perhaps?

Slava

Sat Nov 14 2015, 11:02PM

Registered Member #518 Joined: Tue Feb 13 2007, 05:20AM
Location: New York
Posts: 168

See attached photo..

edit:

... You might be right... I just used an internet inductance calculator...

16.2uH ... I think it's actually 12uH ... I put the wrong diameter into the calculator

edit 2:

Just did it again with the right values... got 13.1uH

DIAM: 0.055
LENGTH: 0.003 meters
TURNS: 10

Signification

Sat Nov 14 2015, 11:22PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

WOW--is that meter right?? My thought..."I wish I could get that kind of L in air-core coils" Maybe the "low batt" is having an effect. can you give a good value of the diameter of the coil and exactly how many turns on the coil connected to the meter--that would help. It is air-core for sure, right?

The formula for the frequency of an LC resonance circuit is f(Hz)=1/[2*pi sqrt(LC)]. Can you solve this formula for, say, "L" by hand--We are so dependent on machines now.

edit: Just had a thought--your meter could be broken, or simply putting "mH" for "uH" Do you have a second way to measure this coil OR a coil of KNOWN "mH's"?

Slava

Sat Nov 14 2015, 11:25PM

Registered Member #518 Joined: Tue Feb 13 2007, 05:20AM
Location: New York
Posts: 168

Signification wrote ...

WOW--is that meter right?? My thought..."I wish I could get that kind of L in air-core coils" Maybe the "low batt" is having an effect. can you give a good value of the diameter of the coil and exactly how many turns on the coil connected to the meter--that would help. It is air-core for sure, right?

The formula for the frequency of an LC resonance circuit is f(Hz)=1/[2*pi sqrt(LC)]. Can you solve this formula for, say, "L" by hand--We are so dependent on machines now.

Here I posted all the data, including coil parameters..

Knowing the inductance value isn't important to me, my tests are based on empirical data. Distance at calculator rest/scramble, using different coils. When I did my second test, I tried to use direct connections instead of using long wires. This made data for low turn coils more accurate. I also used the same coil diameter for all the coils, only varying the number of turns. Ignore the first set of data.

Signification

Sat Nov 14 2015, 11:33PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

I am very familiar with the false HIGH VOLTAGE claims of those ebay modules--I just saw a module rated at 1,000,000 V today! it's like the outrageous claims on the stun gun's millions of voltages--I guess a way to measure it yourself must be found to know what is going on--also the output waveform is strange.

--seems we were writing replies simultaneously here!

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