Delta Pulse

[porkluvr]

Recorded more data. No diode vs MUR460. Didn't get what I expected. Thought the amplitudes would be the same at longer delay times. The no diode recordings are higher. Using pi*L uh*circuit resonance Mhz(no R damp) to calculate R damp. No diode=303 ohms, MUR460=1100 ohms. I used 286 and 1000, a little over damped. I already had a 1k resistor for R damp, paralleled 1k with 400 for 286 ohms The diode in series reduces the current at turn off, might be the cause for lower amplitude. Used a 6 volt supply, 12 volt supply might have less difference. Any other thoughts would be appreciated.

Is somebody trying to pay me back for giving them a headache? (Just kidding, but that chart could give somebody a serious headache.)

[porkluvr]

hi
dear friend i use 450ohm for damping res and my coil near 460mkh and 2.2ohm ( plus coaxial cable near 3.5ohm )for 28cm coil. and this value is best result for my DP.
i test with 680 , 750 and ...1.2k but best result in 450ohm in AIR testing.
i can not find stth1210D in my country so i buy stth12R06D , Do you thing it is work or burn ?
and in finally , Diode help for faster respond and i think can better for Depth , i say OK ?or better say diode cause DP work better ?
can you simulation with my value i say you above and post here.i want know 450 ohm ok or 680 ohm.
regards

Also, Mary, Joe, Tom, and Ezekiel; all of them want for me to be able to simulate their exact circumstances (ha ha). Problem is (one problem, anyway), each of them is incapable of describing the exact circumstances. Another problem is that I don't have TIME for it... and I probably would prove not to be smart enough for it even if I did have the time.

To answer one question, I think that stth12R06D should absolutely be able to withstand any stress Deltapulse PI demands of it (provided that you are using IRF740 MOSFET), but whether or not it would makes things work better, can only be determined by you, by your real-world tests.

You may be able to tell everybody how much inductance and resistance is in your coil, and you may also be able to tell everybody how much resistance is in your cable, (and to be honest, that aspect of the problem had not cross my mind before you mentioned it, and it is also important), but nobody can ever know how much CAPACITANCE is in your coil/cable combination. Very much, too, too, TOO, much guesswork is involved for anybody to be able to determine that for you.

Maybe you should try a shorter length of cable, because 3.5 ohms does seems a bit too much, but then, I have not measured any coax's resistance lately. But, you did not tell what type coax you have, or how long it is (not that I want to want to know)!!

Come on, give us all a break. Spice is a general tool... you ask for detailed answer, but at the same time, you can provide only basic/general information. That is unreasonable.

Here's what I think: All anybody can do is to try and use the best available materials and use the best construction techniques that you can muster. If you have knowledge about the characteristics of the materials you are using, and how your construction techniques react with those characteristics, you can use your best approximation in a simulation to try and find out which direction you need to go. But, NEVER should you expect detailed answers. Hope for the best, but test your test results in a real world scenario ASAP.

GIGO means "Garbage In, Garbage Out". I apologize if I made my it appear that a simulations does not obey that very, very basic rule.

edit: Find out how to measure the resonant frequency of your coil/cable combination. When you can do that; by doing that, you can generally determine the relative merit of the coil/cable combination.

(All other things being the same) making the resonant frequency go higher should result in a better coil... a better coil should result in the capability to take your primary sample sooner in time (having a shorter sample delay).

It is generally considered that a shorter sample delay results in better sensitivity, but I think that that depends on WHAT you are searching for, and also depends on the particular detector you have in your hands!

From what little bit I know, I think that DP is a different animal... it definitely is not, I repeat, NOT comparable to the likes of either Surf PI or the Barracuda... (unless you don't mind comparing apples and oranges... only my humble and untested opinion).

DP is predominately a RELIC (or deep cache, or coins) hunter. (Am I right, KT315??) Do not expect to find a fine gold ring with it, you will probably be disappointed. (That is only my opinion. Some maniac might be able to make me eat those words.)

[green]

Is somebody trying to pay me back for giving them a headache? (Just kidding, but that chart could give somebody a serious headache.)

I apologize for giving you a headache.I was trying to reply to Tepco"s reply #2628

[Under very long pulse condition, large amount of energy released, diode may enter so called “avalanche mode”, at least this particular type. Normally, computer simulation will fail to predict this. Under this condition, circuit behavior can change slightly, producing that famous 1500V peak and significantly influencing detector behavior. Someone with suitable hardware should provide scope pictures, eventually experiment with other diode types under various conditions. Some modern fast diodes are specifically designed to avoid avalanche, ordinary slow types can reach this mode easily, recommended diode is probably somewhere between. It is less known that ordinary 1N5408 rectifier, otherwise too slow to rectify even at audio frequencies can produce very high power nS pulses in avalanche mode. Experiment with different types can be interesting, at this point ignore capacitance and switching speed, try some ordinary ones too.]

I recorded scope wave forms, reply #2631with some different diodes. Adding a MUR460 diode increased the circuit resonance from 345khz to 1.3Mhz. The amplifier out vs time chart in reply #2634 was done to show if there was any improvement with the diode. The sample delay could be decreased from 9 usec to 4 usec . Adding the diode reduced the signal probably by reducing the voltage to the coil. I have been using the diode to get a short delay, but it looks like it hurts except for short TC targets. Sometimes a picture is worth a thousand words, sometimes not.

[mohandes]

Also, Mary, Joe, Tom, and Ezekiel; all of them want for me to be able to simulate their exact circumstances (ha ha). Problem is (one problem, anyway), each of them is incapable of describing the exact circumstances. Another problem is that I don't have TIME for it... and I probably would prove not to be smart enough for it even if I did have the time.

To answer one question, I think that stth12R06D should absolutely be able to withstand any stress Deltapulse PI demands of it (provided that you are using IRF740 MOSFET), but whether or not it would makes things work better, can only be determined by you, by your real-world tests.

You may be able to tell everybody how much inductance and resistance is in your coil, and you may also be able to tell everybody how much resistance is in your cable, (and to be honest, that aspect of the problem had not cross my mind before you mentioned it, and it is also important), but nobody can ever know how much CAPACITANCE is in your coil/cable combination. Very much, too, too, TOO, much guesswork is involved for anybody to be able to determine that for you.

Maybe you should try a shorter length of cable, because 3.5 ohms does seems a bit too much, but then, I have not measured any coax's resistance lately. But, you did not tell what type coax you have, or how long it is (not that I want to want to know)!!

Come on, give us all a break. Spice is a general tool... you ask for detailed answer, but at the same time, you can provide only basic/general information. That is unreasonable.

Here's what I think: All anybody can do is to try and use the best available materials and use the best construction techniques that you can muster. If you have knowledge about the characteristics of the materials you are using, and how your construction techniques react with those characteristics, you can use your best approximation in a simulation to try and find out which direction you need to go. But, NEVER should you expect detailed answers. Hope for the best, but test your test results in a real world scenario ASAP.

GIGO means "Garbage In, Garbage Out". I apologize if I made my it appear that a simulations does not obey that very, very basic rule.

edit: Find out how to measure the resonant frequency of your coil/cable combination. When you can do that; by doing that, you can generally determine the relative merit of the coil/cable combination.

(All other things being the same) making the resonant frequency go higher should result in a better coil... a better coil should result in the capability to take your primary sample sooner in time (having a shorter sample delay).

It is generally considered that a shorter sample delay results in better sensitivity, but I think that that depends on WHAT you are searching for, and also depends on the particular detector you have in your hands!

From what little bit I know, I think that DP is a different animal... it definitely is not, I repeat, NOT comparable to the likes of either Surf PI or the Barracuda... (unless you don't mind comparing apples and oranges... only my humble and untested opinion).

DP is predominately a RELIC (or deep cache, or coins) hunter. (Am I right, KT315??) Do not expect to find a fine gold ring with it, you will probably be disappointed. (That is only my opinion. Some maniac might be able to make me eat those words.)

thanks , and excuse for my English.
i use military ICs , 4538 and 4066 and lf357. I use ne556 and ne555. all res is 0.1percent .
i use military irf740 ( master ) and can produce to 620Vp-p .
use two mode frequency in 500 and 130hz .PW at 90mks to 270mks .
and tl072 i think better than tlo62 , what is your idea ?
regards

[kt315]

DP is predominately a RELIC (or deep cache, or coins) hunter. (Am I right, KT315??) Do not expect to find a fine gold ring with it, you will probably be disappointed. (That is only my opinion. Some maniac might be able to make me eat those words.)

do not see a problem to set a additional knob, simplest mod, by one click it will choice either deep cache or coins.

[porkluvr]

use two mode frequency in 500 and 130hz .PW at 90mks to 270mks .

regards

Taking into account what you wrote in #2636, if that is accurate I think your pulse width needs to be ~300us. Using 90us would be a waste of time.

[mohandes]

Taking into account what you wrote in #2636, if that is accurate I think your pulse width needs to be ~300us. Using 90us would be a waste of time.

dear friend i use selector and i can use 155mks , 180mks , 203mks , 235mks , 275mks . i use 130hz for 1*1coil and 500hz for 45*45 or lower than this size.
i ask many time this question , can i use shielding for 1*1m coil ? YES OR NO ?
IF yes ?
1- i use TENUOUS FOIL
2- i use tinned copper
AND i use 12volt regulator for fix voltage , and it product 11.88v .
regards

edit : dear KT315 i add 22mik tnt caps but red LED on and 4148 burn.
i check again , regards

[mohandes]

i find it
when i connect to lf357 and DA3 red led on and 41418 , VD8 and9 burn.
so where is wrong.
regards

[Jose]

Some comments on my experience with Delta Pulse, I can be wrong or not, but maybe someone will find it useful.
Coil Shield for 1X1 mts.? , If you can use.
How to do it?. I do not know, try tape Scocht No. 24 and did not work.
Blinage in the coils is necessary 1X1 mtrs.?.
It is recommended that coils, weighing less than 20 or 25 microseconds delay be shielded, but coils 1X1 mtrs, generally have a greater than 30 microseconds delay, so it would not be practical in my opinion, shielding these coils.
Minimum time delay, in the Delta Pulse.
You can decrease the time delay making modifications as mentioned in the previous post by KT315, but the minimum you can get is about 17 to 18 microseconds, the issues related to the design of the front of the DP, so I not convenient to use between the MOS and diode the coil, as the main advantage of this diode, is annular MOSFET stray capacitance.
Instead, this dido produces voltage drop, which can affect the power supplied to the coil.
Coil resistance.
The resistance of the coil, with its inductance affects the current flowing through it.
High currents in the coil, producing surges that are difficult to adequately cushion, DP accordingly, becomes unstable.
So I think the coils in the DP should not be lower than 3 ohm resistors, including cable.
Jose

[kt315]

i find it
when i connect to lf357 and DA3 red led on and 41418 , VD8 and9 burn.
so where is wrong.
regards

mohandes, leave this topic. bulgarian pulse star still waits your involving - no your posting there from 2013 year.
anotherway you will burn your dp evermore.

[alimahmoud320]

السلام عليكم
انا عملة الدائرة وهى مش شغالة
اصوات متقاطعة
ارجو الافادة

[Qiaozhi]

السلام عليكم
انا عملة الدائرة وهى مش شغالة
اصوات متقاطعة
ارجو الافادة

Please read the forum rules -> Basic Rules of the Forums
and make your posts in English.

[mohandes]

mohandes, leave this topic. bulgarian pulse star still waits your involving - no your posting there from 2013 year.
anotherway you will burn your dp evermore.

dear KT , ready i want use your changing in DP2 , and just these caps make for me problem.
i wait for your best deeper detector , and i believe you can finish it.
regards and sorry me.

[chafik]

this is a English forum you must use it to get help from nice people here. use google translate for your question.for your question you need to measure frequency for first stage and flow a pdf manual written by kt315 for first step to adjust just type deltpulse in 4shared you will find this manual

[mrmetal]

special thanks to KT315 for share all detail of DP.
KT315 in maximum power signal(maximum Ton),dp how many need current?
for power supplay 12v is better or 12.6 or ...?