miner 4 pcb, schematic,partslist,picture

		Quote:			Posted by xavier
	Hi GD and DK Well it?s the IC?s that are bugging me the most at the moment the LF357N (I found a LM358N and LF353N) CA3140E  MPSA14 and the 2n4403 I want to replace the 2n3773 with an IRF640 or 740 I must still look at the data sheet to see what will be the best but the 640 can go up to 18A. What I need to do is find the right replacement parts or I will have the same problem the next time I want to build one not only that but I want to start a MD club in my area as there are non so I may need to build quite a few over time to come. Regards Xavier

I'll rummage through my parts bins tomorrow and let you know what I can do for you.

The transistor cannot be substituted with a FET.


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Thanks DK and GD

 If I were living in Johannesburg I should have no problem finding the parts but I live out in the bush and the nearest town that I can get parts from is 90km from me and they only stock the most common parts but not to worry I will find them it will just take me a while longer that?s all.

Regards Xavier 


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Xavier

Hi sabloni,

there is no problem with stability of this circuit at all. It will be quiet with sensitivity and power at max. if there's no metal near the probe. Don't worry, it's not like XR71 at all.

regards,
d.


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Hi sabloni,

i don't know how xr71 could go since i suppressed the semplers OPAMP and sold it as a good 2m detector (in air), not better. I heared it could do 4.2m with 1m x 1m (in air) but i do not believe it. There is one emarged at our local classifieds, i gave a man a call, it was wery professional looking box, all signs pressed, coil casted in professional looking plastic, all wery neet. The man claimed it can do 4m but when i turned the box on and push the sensitivity button, it was pretty much the same s**t.

The miner4 can do good 3m with 1m x 1m coil in air, and cuts threw the soil wery good, providing a solid power supply (two heawy lead-acid batteries in series) to feed its juicy pulses. I have found items at 2.5m in dry soil but i have never realy tested it by berreing the items. If you are planning to use it with NiCd or NiMH rechargabels do not forget to add extra 30.000uF capacitors, the current limiting resistor and extra 30.000uF or you may find to recharge your batteries exactly 3 times. I have learnd this the hard way. Oh, the "discriminator" works well down to some 20 or 30 cm. (using small coil) and discriminates para-ferro magnetics/diamagnetics.

The DBP can go to good 4m in the air, and it is more simple to use and more reliable than Miner4 i have tested it in rather dry soil down to 2m and it worked without a problem ( i am lasy digger) which works for me. I have also tested it in carbonate sand i have for building purposes down to 3m, without a problem again. I recently found a 10L pot down to some 1.5m in wet forest soil which is quite impresive considering the size of object, the Miner4 couldn't do this. I belive in poor conditions this device is steel capable of some 2m depth.

regards,
d.


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miner4 and other pi download at pulsdetektor.de for me i download all those pi's there to study the schematics, i'm planning to use the output stages of those pi's maybe powerful. drivers and igbt's, supressors,zeners,resistors output and input stages to be used in dp and dbp or xr71 and other pi's for more powerful pi's. but when i checked those parts availability in my place i found out that those plans of mine is only a dream even it is possible to do in reality but impossible in my place to have those electronic parts.so....it remains in my dreams....my friends in other country, you'r so blessed and very lucky that you have all the parts and tools needed on electronic projects.

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