Hello zed engineer, thank you very much! I'll try to build the circuit and try the effect!
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Full m/lab SD2000 schematics
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The blocking fets are used to protect the preamp from the high voltage flyback. The delay turn on should be set to a point when the flyback has settled to a voltage that is within the supply voltage of the preamp less than +5v. As a practical matter for this circuit there may be a delay in the fets closing and some other factors. This delay will also very with different coils, depending on their SRF's. Zed or Mechanic will know, maybe they will see this and give you advice.
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Altra is correct,the receive fets switch the pre amp away from the coil during the flyback period,once the flyback voltage settles close to zero volts then the preamp is re connected back to the receive coil,The blocking action should finish before the first sample begins.
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Hello everyone. It turns out that the opening of the VN2410/ZVP4105 transistors can be shifted almost to the first sample and the sensitivity will not change from this. And why is the first sample taken so late? If the attenuation of the coil is ~15 us plus the time to open VN2410/ZVP4105, then probably the first sample can be taken probably after ~20 us and the sensitivity will increase,and it is taken after 45us
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Originally posted by Andrei View PostHello everyone. It turns out that the opening of the VN2410/ZVP4105 transistors can be shifted almost to the first sample and the sensitivity will not change from this. And why is the first sample taken so late? If the attenuation of the coil is ~15 us plus the time to open VN2410/ZVP4105, then probably the first sample can be taken probably after ~20 us and the sensitivity will increase,and it is taken after 45us
[ATTACH]55418[/ATTACH]
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[КУОТЕ = N@sko; Lm394 replace with Ad797.On video detector use sd2100 timing.Shalow target is iron,deep target is 20 eurocents at 25 centimeters in low mineralised ground.
Hi N@sko! I tested also in low mineralized ground SD2000 time as in the original time diagram SD2000, 20 euro cents depth 25-30cm on the CH2 and on channel 1 is shallower however I have the reverse tone on a 20-cent coin. Whether the time base is in question or or you are in geb turned the signal ? To me it's actually more interesting time diagram with which to achieve greater depth of coins ?!
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Originally posted by kt315 View Post[КУОТЕ = Н @ СКО; 205725] Лм394 замените Ад797, користите пиц фот пусле.На видео детектору користите сд2100 тајминг. Плитка мета је гвожђе, дубока мета је 20 евроценти на 25 центиметара у ниско минерализованом тлу. [/ КУОТЕ]
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My 4105 output has 62k interference, as shown in the figure below. I don't see 62k interference?Attached Files
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