please helppppppppppppppppp

		Quote:			Posted by mz6466
	tank you dear i find this schematic in geotech forums.i finish build my metal detector.but not cut alarm to complete .what?

Wow, that was quick!


Coils are the hard part. They need to be very accurate and stable. They need to be coated so the wires do not move around with

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. You can't use just any old glue/paint from the hardware store, because it would hurt the coil Q and possibly stop the oscillator. They are not something that you do quickly.

		Quote:			Posted by {author}
	what is d1 and d2 number???i insert 1n4148 replace because i can not read number.

From what I can see the number is sfd108. This appears to be a germanium diode. I would not use the 1n4148 as that is a silicon switching diodes, and these have a different forward voltage drop of .3v. I would not use a silicon diode in this meter circuit. A 1n34A (germanium) should work here though.



Well I will if I can. But it's pretty difficult for me to do so, I can't see what you are doing! Plus I don't have a large amount of time. Can you post pictures? Honestly though, I bet if you want me to help get this thing to work, you'd have to mail it to me!

Edit: You have been working hard on this. You need to put it aside for a while, get some sleep and eat some food. Then when you come back, you will find several mistakes that you made. I bet that you made some mistakes with the board etch/layout as well. You need to check all your work. It happens to the best of us. Plus, I'm not sure I trust the original schematic too much.

		Quote:			Posted by mountaindweller
	You have the patience of a saint Technos, well done mate.  cheers   steve

Not so fast, they don't have a working detector yet!!   

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