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It’s About Amps And Not Volts......??


Tony

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Thanks for all of this interesting information......

So, in essence, it’s the culmination of the;

1. The square boxy bit with the buttons and knobs

2. The round thingyamejig at the bottom

.........and everything in between.

It appears that Minelab do make a good version of the above and manage to keep all of the smoke from escaping.

 Tony 

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First of all, "power" is a wrong metric for metal detectors. A single-frequency VLF with a perfect TX coil will transmit zero power since all the current gets recycled. A traditional PI has a total loss transmitter but even then "power" doesn't make much sense.

For the "transmit strength," yes, it is current that matters along with the number of turns of the TX coil. We call that the "ampere-turns" (N*I) and the TX magnetic field is proportional to N*I for a given coil size. It doesn't matter what the driving voltage is except that it is part of the system design.

As Pimento suggests, you can't look at the battery current and tell anything. TX pulse width and pulse frequency also combine with peak TX current to determine average battery draw. And once you know the peak current, that doesn't necessarily reflect actual performance. For small nugget detection you need to be able to sample early and the higher the peak current the harder it is to do that. Early sampling isn't important for an Atocha bar detector so you can dump 100 amps of current through the coil, but that same system might not be able to detect any nuggets smaller than, say, an ounce. At all.

Finally, there are methods of energy recycling in PI detectors, although not yet prevalent in production models. Another reason why you can't look at battery consumption and determine anything.

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10 hours ago, Geotech said:

First of all, "power" is a wrong metric for metal detectors. A single-frequency VLF with a perfect TX coil will transmit zero power since all the current gets recycled. A traditional PI has a total loss transmitter but even then "power" doesn't make much sense.

For the "transmit strength," yes, it is current that matters along with the number of turns of the TX coil. We call that the "ampere-turns" (N*I) and the TX magnetic field is proportional to N*I for a given coil size. It doesn't matter what the driving voltage is except that it is part of the system design.

As Pimento suggests, you can't look at the battery current and tell anything. TX pulse width and pulse frequency also combine with peak TX current to determine average battery draw. And once you know the peak current, that doesn't necessarily reflect actual performance. For small nugget detection you need to be able to sample early and the higher the peak current the harder it is to do that. Early sampling isn't important for an Atocha bar detector so you can dump 100 amps of current through the coil, but that same system might not be able to detect any nuggets smaller than, say, an ounce. At all.

Finally, there are methods of energy recycling in PI detectors, although not yet prevalent in production models. Another reason why you can't look at battery consumption and determine anything.

I actually understood most of this as I have read plenty of basic PI theory.

But surely the Flux Capacitor must play a big part in all of this 😉

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11 hours ago, Chase Goldman said:

First Texas is working on that one...

You mean on the “Time Ranger Pro”.........maybe Steve can check for those special capacitors 🤫

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