Post by Gary Lecomte on Feb 27, 2006 6:53:32 GMT -8
1) This is a Very Complex Question, But before you can calculate that transformer you need to know much information. The "AL" Value of the Ferrite Core. The frequency of operation. The pulse Cycle and waveform. Both input and Output Voltages. Both input and output currents.
And even than there is no complete formula that I have found. It Still requires some expermenting, Especially for the Extreme High Voltages on the output of this circuit.
2) The Diodes/Capacitors Create a Voltage Multiplier circuit.
My Personal Interests include: Analogue Electronics, Woodworking, Metalworking, Inorganic Chemistry, Swimming, Camping, Kayaking and Vegetable Gardening.
Can you explain how is it possible? During almost 5 years we do a research on this, but we still do not know theorethical background of "pulse transformer" like this. It's a kind of "TOP SECRET" maybe because there' totally NO info ANYWHERE We have a huge forum on this, with hundreds of people tried to make it, but no one was able to construct it to be effective. So, we found a way to pass it.
But for me, it's clear scientific interest. If you know how this transformer can be calculated, please tell me. I also can write software for others to use further.
I do not ask how to make a transformer. I ask how to calculate it. And what theory lays behind.
Just "many turns" "thin wire" and "excellent insulation" won't do it. I have made many of these transformers. With 4-5 cm sparks without internal shorting. And yes i've used proper ferrite, #77 as you call it (permeability=2000). And good insulation - special teflon type for high voltage applications. And vacuum process even. And what? The same rezult: it only "zaps" not more. For real efficency it needs real calculation process, which is unavailable.
I would not ask if i wanted to make deadly stun gun. Because i've already made it. But i'm interested in physics of the things like that.
I'm saying again, i want to know HOW exactly it operates and WHAT principles involved. At least... And with formulas it'll be twice good )) I'm totally not interested in actual construction. So the fact i already know how to make it changes nothing here.
PS As for software, i mentioned it because we are planning to release an ultimate program for electronics and other technical calculations. And more than just calculations - datasheets, references, etc. At now we're gathering ideas what to include there.
Post by Gary Lecomte on Mar 12, 2007 15:23:27 GMT -8
i want to know HOW exactly it operates and WHAT principles involved. At least... And with formulas it'll be twice good )) I'm totally not interested in actual construction. So the fact i already know how to make it changes nothing here.
Sorry, Doesn't make sense to me. If you Already Know how to make it than you should know how it works.
And there are Too Many Possible Formulas, Depending on How you want to make it.
First there is a Power Oscillator. It could be one of MANY Different Designs. It Needs to Feed a Transformer to be Stepped up in Voltage. It also Needs to be Relatively HIGH Current if you want high power out. How High of a Voltage, is Totally up to what you want. There Really is No Optimum. But when Rectified, Most Vary between about 150 to 400 Volts DC Ideally for T1, you need to design a Special transformer for that to get best efficiency at the Frequency you have chosen for you Oscillator.
So to Start with, you need a Transformer core and determine its "AL" Value in order to design an Efficient Impedance Match. You also need to determine What Voltages and Currents you want to operate at. Also considering the Various types of batterys Available and the Currents they can Deliver.
Stun Guns Need a Lot of CURRENT, So a Battery with Low Internal Resistance is Required. Lithum Battery are about the Best today.
These Oscillator and Transformers formulas are Readily Available from many sources.
Than you need Either an SCR fired Trigger or a Spark Gap to set the pulse rate to the Output transformer. Pretty Standard stuff, just make sure your SCR can handle the Voltage Spikes
And lastly you need to design T2, Which is really the same as in Designing T1. Its Just Different Input/Output Voltages and Frequency.
As to Exact Formulas, Without an Exact Example of the Oscillator and its frequency, its nearly impossible to give you formulas. There are Too Many that May or may not Apply.
(AL Calculations are on my Website) Also, the "ARRL" (Radio Amateur Handbook) can give you Many of these Formulas.
Hope this HELPS, But I have better things to do than Write this article for you and try to cover All Possible Variations. Besides I'm a Slow Pick and Peck Typest. This write-up took me 30 Minutes.
I once developed one of the smallest transformers of its type out of ferrite core for the navy. it now has a US patent. each half is not a perfect fit. you must use a fine grit sand paper until the max inductance is reached. this translates into max power. most of the shelf cores are only 70 percent at best. The primary at the operating frequency must be of the impedance which will not load the circuit down . You are stepping voltage and very little current. the impedance of the primary is easy to calculate and should be ten times the output impedance of the drive circuit and the secondary will take care of itself. You should also use a nylon bolt and a large washer. this distributes the stress. With two half's of a core attached one can even rotate one on the other and see a change in inductance. The type of ferrite can allow your transformer to be half the size of a core made from a different ferrite. smooth surfaces can double the power rating . tight winding is of most important . Just apply some glue at the end of a tight wind. leave a good 4 inches of extra wire sticking out . The wire size should not be critical as the proper building of a core. You can purchase ferrite which will produce the inductance you need and the power with half the size . the secret is an exact fit and a tight winding.
Hello to all! I want to know if replacement exists for EC140M, to reason that in my country Argentina I it cannot find and not to find replacement searching in Internet. Someone can help me? THANK YOU VERY MUCH
Taking a look at Gary's circuit, the EC104M is just a SCR (silicon controlled rectifier) with a 600 Volt rating and the ability to carry .8Amp or greater. These are easily obtained on the internet. When I am not at work , I will find you a link--if someone else doesn't respond earlier than I can. rmeyn