Silverdog Surf pi Daming resistor

[green]

Little Update on how this whole damping resistor thing went lol basically the appointment with local electronic shop was a bust! The gentleman offered me the use of the scoop and a variable resistor tool, but could not take the time to help me with it, Sadly I never seen let alone used a scoop so ! as nice as his offer was I am no further ahead, But he did offer me his tools anytime free of charge, So if I can learn how a scoop works I could use his. seems cheaper then buying one Right lol but how hard is it to learn how to use one without having one. Anyways, so coming back home I used my bread board and made the resistor tool that Giaozhi kindly drawn out after many hours of dancing with changing resister value ( which to take a measurement I had to unplug the coil, measure resistor, and plug it back in) fallowed by many a pond many air test and delay tuning, HAHAHAHA as you all can guess its not working out so well, For time being I settled on a 565 Ohm resistor which seems to work But ...... I still can't get more then 7"on a usa nickel and its scratchy at best. Brings me to a question, Is it even possible to reach 12 inch or more in depth with the sur pi 1.2?

What size coil are you using? Did you purchase a surf PI kit? Maybe the kit seller could suggest a detection distance for a US nickel for the coil size you are using.

When learning to use a scope be sure to have the probe on x10 when looking at coil volts. I used a scope a lot before playing with PI's not needing x10 probe. Learned the hard way my scope probe didn't like 500 volts on x1.

[Tibuck19]

Now that I got a scope I bought an older Gould 15Mhz dual beam 2 channel thing of a bobber, lol Now what? I connected to TP1 with first channel and TP2 with second channel, I made a resistor tool 220om with a 2Kom on a 25Ktrimpot, Does any of you have a screen shot of the best resistor value looks like?

[kt315]

do you need the direct link on the wellfamous article of Carl Moreland for a magazine or what?


Hammerhead
Pulse Induction Metal Detector
by Carl Moreland
Revision 1.5 — 21 July 2006

[Tibuck19]

do you need the direct link on the wellfamous article of Carl Moreland for a magazine or what?


Hammerhead
Pulse Induction Metal Detector
by Carl Moreland
Revision 1.5 — 21 July 2006

I Googled it and came across the article you mention, Am I to understand no mater if its a surf pi or hammerhead or MMP , all the PI has a similar curve ?

[homefire]

I Googled it and came across the article you mention, Am I to understand no mater if its a surf pi or hammerhead or MMP , all the PI has a similar curve ?

Pretty much so. Some will be faster and some slower. Depending on the Set up and Speed coil can dump flyback.

HF

[Qiaozhi]

I Googled it and came across the article you mention, Am I to understand no mater if its a surf pi or hammerhead or MMP , all the PI has a similar curve ?

It sounds like you would benefit greatly by purchasing a copy of Inside the METAL DETECTOR - Second Edition - Published 2015

[Tibuck19]

It sounds like you would benefit greatly by purchasing a copy of Inside the METAL DETECTOR - Second Edition - Published 2015

Yes indeed, it certainly does, it is on my "defiantly must get" list.

[Tibuck19]

Pretty much so. Some will be faster and some slower. Depending on the Set up and Speed coil can dump flyback.

HF

Thanks

[Idefix]

Hello,
The damping resistor avoid to have too many ripples on the flyback voltage.
When at the good value of damping resistor, the voltage at the input of the OPA is at the values to be amplified without saturating. So it makes the circuit quicker.
Also, as small is the parasitic capacitor, and as hight the frequency of the ripples is , (or as short in period time there are) so smaller input value is , quicker the amplifying is possible.
I will try to attach a spice capture, with 4 different values or damping, on a 300µ coil.

[eolte]

Para obtener la resistencia de amortiguaci?n adecuada al tama?o de la bobina que se utiliza, se puede colocar en serie con la resistencia utilizada, una olla de aproximadamente 500 omhs, desde all? se puede variar hasta obtener la distancia de detecci?n m?xima con el tipo de bobina utilizada . [quote = nonkapo; 249262]. en el archivo pinokio para modding barracuda de kt315 que se recomiendan en las l?neas de alimentaci?n del 5534 para la supresi?n del ruido [/ quote]

[Qiaozhi]

Para obtener la resistencia de amortiguaci?n adecuada al tama?o de la bobina que se utiliza, se puede colocar en serie con la resistencia utilizada, una olla de aproximadamente 500 omhs, desde all? se puede variar hasta obtener la distancia de detecci?n m?xima con el tipo de bobina utilizada . [quote = nonkapo; 249262]. en el archivo pinokio para modding barracuda de kt315 que se recomiendan en las l?neas de alimentaci?n del 5534 para la supresi?n del ruido [/ quote]

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

[Carl-NC]

Para obtener la resistencia de amortiguaci?n adecuada al tama?o de la bobina que se utiliza, se puede colocar en serie con la resistencia utilizada, una olla de aproximadamente 500 omhs, desde all? se puede variar hasta obtener la distancia de detecci?n m?xima con el tipo de bobina utilizada . [quote = nonkapo; 249262]. en el archivo pinokio para modding barracuda de kt315 que se recomiendan en las l?neas de alimentaci?n del 5534 para la supresi?n del ruido [/ quote]

Please post in English, thanks.