Previous in Forum: Should Voters in PA Ban Fracking?   Next in Forum: Why Are Some of Us Not Threated by the Web's Location Feature?
Close
Close
Close
24 comments
Member

Join Date: Nov 2013
Posts: 5

High Voltage Questions

04/25/2016 11:41 PM

I have generated a High-Voltage spark which jumps a 30mm Spark gap. What would an estimate of the voltage be for such a spark. How can I test to determine if the voltage is AC or DC? What diode/circuit can I use to rectify it if it's AC to a DC voltage? What Diodes are capable of handling such voltages?

Register to Reply
Pathfinder Tags: DC high voltage
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
2
Guru

Join Date: Mar 2012
Location: Out of your mind! Not in sight!
Posts: 4425
Good Answers: 107
#1

Re: High Voltage questions

04/25/2016 11:47 PM

So you have a high voltage spark and want to know the voltage? Well I guess it was high!

Voltage AC or DC? Really? How did you generate the Voltage?

You are possibly playing with your life here. So better read up and learn before doing.

Diodes have ratings. Try not to define the Voltage by touching blank wires unless you know what currents flow in your system.

You are trolling this forum, right?

__________________
Common Sense Dictates
Register to Reply Good Answer (Score 2)
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4357
Good Answers: 53
#17
In reply to #1

Re: High Voltage questions

04/27/2016 1:33 AM

Good advice! You may have saved this guy's life.

__________________
Enjoy and be happy! Life is too short!
Register to Reply
Guru

Join Date: Oct 2008
Posts: 42290
Good Answers: 1662
#2

Re: High Voltage questions

04/26/2016 12:14 AM

Bill's sister is his brother's mother. His next door neighbor is his father's uncle.

What is his father's name?

No, it's not Dad!

Register to Reply Score 1 for Good Answer
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4357
Good Answers: 53
#16
In reply to #2

Re: High Voltage questions

04/27/2016 1:33 AM

Bill Cosby?

__________________
Enjoy and be happy! Life is too short!
Register to Reply
2
Guru
United States - Member - Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - RC Aircraft - New Member Engineering Fields - Aerospace Engineering - New Member

Join Date: May 2009
Location: Saint Helens, Oregon
Posts: 2215
Good Answers: 69
#3

Re: High Voltage questions

04/26/2016 1:42 AM

You've been a member of this forum since Nov. 2013 and this being your first question(s). And not knowing how you created a high enough voltage to jump a 30mm gap? You need to stop where your at and find a friend or somebody that knows what they're doing with electricity, because you obviously don't and could be the making of a Darwin's Award winner. We don't know what your input voltage is/was, AC/DC or what kind of transformer you used to step up the voltage.

You need to get yourself educated in electrical theory before you kill yourself and maybe a friend too, that's dumb enough to watch your little experiment.

__________________
Confucius once said, “ Ability will never catch up with the demand for it".
Register to Reply Good Answer (Score 2)
Member

Join Date: Nov 2013
Posts: 5
#4

Re: High Voltage questions

04/26/2016 2:28 AM

The HV is generated by an ne555 as an oscilator driving my own wound primary on the ferrite core of a TV transformer. Due caution is taken & a chicken stick is used as a probe. Some hv tv transformers have an inbuilt rectified to produce the HV DC but I am not sure if mine has it built in.

Register to Reply Score 1 for Off Topic
2
Guru

Join Date: Mar 2012
Location: Out of your mind! Not in sight!
Posts: 4425
Good Answers: 107
#7
In reply to #4

Re: High Voltage questions

04/26/2016 8:26 AM

What's the chicken stick for? What is needed is a book and a handful of experience in electrical and HV engineering and safety practise.

Stay safe!

__________________
Common Sense Dictates
Register to Reply Good Answer (Score 2)
Member

Join Date: Nov 2013
Posts: 5
#23
In reply to #7

Re: High Voltage questions

04/27/2016 8:55 PM

Thanks to all for all the valuable advice which is greatly appreciated.

The chicken stick is a dowel stick (mine is about 750mm in Length) and is used as a probe for sparking.

The HV output insulated wire from the TV transformer is only attached at the end of the stick.

The other end of the stick away from the & HV wire, is only held.

I am working on a glass topped table and keep far away from the HV Transformer and the wire attached to the Chicken Stick. After I run the circuit I switch it off, disconnect the power and discharge it by shorting the HV lead to Ground.

An NE555 is connected as an oscillator generating Square waves and feeds my own primary coil wound on the TV transformer.

I previously experimented with a Cockcraft Walton circuits with about 5 & 10 Stages also driven by an NE555 oscillator powered by a 9V battery to generate the high voltage but the voltage produced seemed to be very low as the spark was only about 1mm long. Maybe I used the wrong type of caps.

Register to Reply
Guru

Join Date: Mar 2012
Location: Out of your mind! Not in sight!
Posts: 4425
Good Answers: 107
#24
In reply to #23

Re: High Voltage questions

04/28/2016 3:50 AM

Well, looks like you are still alive. But as said before your experimental approach to electricity might get you a Charles Darwin award at its best or a shock (either electrical or from the fire insurance bill).

Your question is clear indication of missing knowledge and it might be wise to head some of the advice being given to read more before you turn the generator on again.

I would start with a definition what a "wrong type of cap" is. You can gain important knowledge on caps which you need when playing around with them.

What is it you want to achieve? Just the spark? Or anything more sinister?

__________________
Common Sense Dictates
Register to Reply Score 1 for Good Answer
Guru
Popular Science - Cosmology - New Member Technical Fields - Technical Writing - New Member Engineering Fields - Energy Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electromechanical Engineering - Old Member, New Association

Join Date: Apr 2008
Location: Lexington, KY
Posts: 1640
Good Answers: 72
#9
In reply to #4

Re: High Voltage questions

04/26/2016 2:18 PM

Since your 555 is most likely producing a square wave the TV transformer is charging up the ferrite with magnetic energy while the output of the 555 is high (i.e. conducting current through your primary coil). That energy is being released all at once when the current is suddenly cut off and the voltage spikes because inductors do not like to have the current flow disrupted.

The formula that would calculate the peak voltage requires specific knowledge about amount of stored energy, characteristics of the ferrite type, and number of windings on the high side as well as some other things.

Because it is driven by a square wave, it is not DC. It is bursts of energy that has the potential of overheating your transformer due to high currents for a short amount of time. When you get the spark, you are more or less creating a short circuit at the output of the transformer. Don't look for it to survive very long.

__________________
A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Register to Reply Score 1 for Good Answer
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8778
Good Answers: 376
#10
In reply to #4

Re: High Voltage questions

04/26/2016 3:48 PM

Due caution is taken

Well it better as TV transformers can produce enough current and voltage to kill.

What exactly are you trying to do or build as there is likely a much safer way to get the same result?

__________________
jack of all trades
Register to Reply Score 1 for Good Answer
Guru

Join Date: Apr 2010
Location: About 4000 miles from the center of the earth (+/-100 mi)
Posts: 9046
Good Answers: 1031
#11
In reply to #4

Re: High Voltage questions

04/26/2016 6:49 PM

Be very careful...

Is the output AC or DC?

You could connect the output of the HV to a high voltage capacitor (or Leyden Jar) and turn it on momentarily.

Check the voltage on the capacitor. If there is still voltage, there is a blocking diode and the output is DC. If there is no blocking diode (AC output), the capacitor will discharge back through the flyback secondary coil and there should be no voltage.

Register to Reply Score 1 for Good Answer
Member

Join Date: Nov 2013
Posts: 5
#14
In reply to #11

Re: High Voltage questions

04/26/2016 10:47 PM

I ran the circuit with a small value 240V rated cap connected to the secondary for a second and checked for voltage on the disconnected cap. There was a very small spark from the cap when shorted.

Does this confirm that there must be a diode within the Transformer and a DC voltage is output?

Register to Reply
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4357
Good Answers: 53
#19
In reply to #14

Re: High Voltage questions

04/27/2016 2:08 AM

Syd, I'll tell you about another story. The output of your transformer is much higher than 240V. It's not safe.

Read my story about my childhood experience with transformers. I'll add something to our story. We had some 100V caps sitting around - electrolytics. We thought it would be fun to see what happens when you run high voltage ac through them. Some just leaked, while others exploded. We were smart enough to run long leads of wire and to place the caps around the corner. We did the same test with diodes and transistors. Most did nothing, but burn out, but a couple did explode.

The moral of the story, don't put a 240V cap on a high voltage transformer. Yours is rated for 240V and I know you have much more than that.

__________________
Enjoy and be happy! Life is too short!
Register to Reply
Guru
Popular Science - Cosmology - New Member Technical Fields - Technical Writing - New Member Engineering Fields - Energy Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electromechanical Engineering - Old Member, New Association

Join Date: Apr 2008
Location: Lexington, KY
Posts: 1640
Good Answers: 72
#21
In reply to #14

Re: High Voltage questions

04/27/2016 12:28 PM

No. The capacitor charges because it is the collapse of the magnetic field always in the same direction. The peak voltage is always positive (or always negative) with respect to ground because when the 555 turns off, it is always disrupting a charging cycle in the same falling edge. This is because the portion of the square wave that charges the magnetic field is always of the same polarity. There is no energy put into the magnetic material when the 555 is in the off state.

__________________
A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Register to Reply
Guru
United States - Member - Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - RC Aircraft - New Member Engineering Fields - Aerospace Engineering - New Member

Join Date: May 2009
Location: Saint Helens, Oregon
Posts: 2215
Good Answers: 69
#13
In reply to #4

Re: High Voltage questions

04/26/2016 9:37 PM

Back on the farm, I had a 17 hand Stallion I couldn't keep corralled in an 8 foot barb wire fence. And that's what your trying to do here. Experience is expensive, rather it's live stock or live electricity. It takes a through understanding, to be able to corral hot stock! They both will bite you in the ass, when your not look'n!!

__________________
Confucius once said, “ Ability will never catch up with the demand for it".
Register to Reply Score 1 for Good Answer
Guru

Join Date: Aug 2012
Location: Land of Fruits and Nuts
Posts: 4357
Good Answers: 53
#18
In reply to #4

Re: High Voltage questions

04/27/2016 1:53 AM

Okay Syd, I'm going to let you know about an experiment I did as a kid and yes, my friends and I all survived.

My friend's brother had "acquired" some big transformers (from large neon monument signs). We hooked the primary to 120VAC and the secondary we hooked up some carbon rods with lots and lots of electrical tape, which we used as handles. We got some pretty big arcs going. No, we didn't use any eye protection, so I'm pretty sure we burned up something in our eyes. We then used our home made welder to melt glass and we did some other cool stuff. I got a good shock when I brushed against the outside of the transformer with my arm.

So, I am not recommending you do anything like what we did. I just had a story to tell.

A little advice; don't mess with high current, high DC voltage. Also, if you get shocked with AC current, make sure your hands can't clamp down on the electrode - touch things with the back of your hand. Also, if you're going to get shocked, make sure it's on one arm. If the current goes from one arm to the other, it'll go through your heart - your heart doesn't like that. My best advice is to learn about safety working around high voltage before paying with it.

__________________
Enjoy and be happy! Life is too short!
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30310
Good Answers: 817
#5

Re: High Voltage questions

04/26/2016 3:02 AM

A1) In dry air, around 90kV or so.

A2) It depends upon whether there is a transformer with an alternating current feeding the spark, which the forum does not know as the equipment cannot be seen from here.

A3) Google "high voltage rectifiers".

A4) as A3.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
Posts: 4348
Good Answers: 180
#6

Re: High Voltage questions

04/26/2016 6:37 AM

Much depends on the shape of the arc gap something a jacobs ladder relies on.

I'll echo the warnings given by others, HV isn't something to play with if you don't know what you're doing.

__________________
The reports of my death are greatly exaggerated.
Register to Reply Score 1 for Good Answer
Member

Join Date: Nov 2013
Posts: 5
#15
In reply to #6

Re: High Voltage questions

04/26/2016 11:04 PM

What was the voltage used to produce these effects & how did you generate the voltage?

Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 30951
Good Answers: 1727
#8

Re: High Voltage Questions

04/26/2016 9:38 AM
__________________
Break a sweat everyday doing something you enjoy
Register to Reply
Guru
United States - Member - Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - RC Aircraft - New Member Engineering Fields - Aerospace Engineering - New Member

Join Date: May 2009
Location: Saint Helens, Oregon
Posts: 2215
Good Answers: 69
#12

Re: High Voltage Questions

04/26/2016 9:18 PM

This guy/girl is over their head and any further information provided to them could lead to their demises.

The OP Has Not Provided Any Information That He/ She Has Any Idea Of What They Are doing!!

> UN-SUBSCRIBE<

__________________
Confucius once said, “ Ability will never catch up with the demand for it".
Register to Reply Score 1 for Good Answer
Guru
Hobbies - Model Rocketry - New Member

Join Date: Jun 2007
Location: East of Seattle, Washington state Republic of the 50 states of America
Posts: 2046
Good Answers: 36
#20

Re: High Voltage Questions

04/27/2016 3:05 AM

Sounds like questions for a quiz.

If not, you are playing with lightning that doesn't always act like you would think.

HV and Rf burns are no joke.

Sorry to sound like a broken record but learn and understand, at the very least, basic electronics before even bothering to study High Voltage.

Playing with TV parts can have some very HV and have killed people who thought they knew what they were doing.

__________________
(Larrabee's Law) Half of everything you hear in a classroom is crap. Education is figuring out which half is which.
Register to Reply Score 1 for Good Answer
2
Guru
Hobbies - Model Rocketry - New Member

Join Date: Jun 2007
Location: East of Seattle, Washington state Republic of the 50 states of America
Posts: 2046
Good Answers: 36
#22

Re: High Voltage Questions

04/27/2016 1:32 PM

Just had a thought. If you are going to experiment with this type of high voltage why don't you switch to automotive coil with points.

If it bites you it will hurt like hell but you will probably live.

Learn why and how with some basics studies.

Just my two cents worth.

__________________
(Larrabee's Law) Half of everything you hear in a classroom is crap. Education is figuring out which half is which.
Register to Reply Good Answer (Score 2)
Register to Reply 24 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Autobroker (4); dj95401 (3); IdeaSmith (3); jack of all trades (1); lyn (1); NotUrOrdinaryJoe (2); PWSlack (1); Rixter (1); SolarEagle (1); Syd (4); TonyS (1); U V (2)

Previous in Forum: Should Voters in PA Ban Fracking?   Next in Forum: Why Are Some of Us Not Threated by the Web's Location Feature?

Advertisement