felezjoo PI(the best pulse induction metal detector that I made until now)

[nick holas]

many thanks WM6,i haven t see this short circuit!!!! you must have a good magnifier !!!!!
i post the corrected sprint layout 6 file some every one could modify it
TYPON 2.zip
for wiltran
the hex is donwlodable in first post file in the zipped archive

[Qiaozhi]

hi pluto923
thanks for your help ,but in fact ,its for sending files in my reply ,i can join image,video but i can t join sprint layout files!!!

Compress the file as either zip or rar, and then use Manage Attachments.

[WM6]

Wiltran, look at attachment in 1st post in this thread (started by koohyar).

A little retouched nick layout:

[Wiltran]

Is there a hex file available for this?

[WM6]

Very nice. Thank you nick.

Please check this (arrow), cause it could lead to short circuit:

[nick holas]

hi pluto923
thanks for your help ,but in fact ,its for sending files in my reply ,i can join image,video but i can t join sprint layout files!!!

[nick holas]

hi wm6
here s your board :75mmx78.6mm

[pluto923]

On the left side menu choose Save this file as xxx.LAY. And ready

[WM6]

BMP is ok for BW. Thanks.

[nick holas]

hi all!!!
hi bernt,it s nice to read you!!!
i ve corrected the layout with thermal pads ,but don t know how to post file!!!!
WM6:
i can give it ,only in bmp format .sprint layout export B/W file only in bmp!!!

[WM6]

hi all
i ve made sprint layout pcb,if some one want??
[ATTACH]33385[/ATTACH]

Nice work nick.
If you can ad black-white one .jpg, it would be great.

[pluto923]

Hello Nick, please give board in format Sprint Layout
if possible

[bernte_one]

hello nick

just put them in the message Attachement as zip Container, thanks

you could add thermal pads on the solder points which are on the massive plain

[nick holas]

hi all
i ve made sprint layout pcb,if some one want??

[Qiaozhi]

I would like to discuss R5 which is 2.2k , I've seen similar ccts, with the resister being as high as 10K such as the Skif PI
what concerns me a bit is that circuit configuration will dump the 12v onto the gate of the IRF840
but wont the high value of resistance 2.2k (up to 10K) limit the current into the gate and not fully turn
the fet on ?

Unlike bipolar transistors (which are current-driven), MOSFETs are voltage-driven. From the IRF840 datasheet you can readily see that Vgs threshold is 4V (max), which means that it needs to have at least 4V to turn on (and preferably much higher) up to the maximum rating of 20V. From the datasheet graphs, it is clear that Id plateaus at about Vgs=8V. This means that the resistor value of 2k2 is perfectly ok, as this will apply 12V to the gate. MOSFETs have a very high input impedance, and (from the datasheet) it is possible to calculate this value for the IRF840 as being 200M (from Vgs=20V and Igss=+/-100nA). So there is no need to be concerned about gate current. In fact, a value of 10k would work just as well as 2k2.