TGSL 100x100mm build questions

[yatahaze323]

Yatahaze pay attention to the transistors pins! I think that you have misplaced the Jfet J107 it's not BF245, it wont work that way!

I was looking at the Datasheets for the J107 and the BF245 and it appears that they have the same pinouts. I'm assuming that since they have the same pinouts for the Gate Source and Drain pins that they are in the correct orientation. I was also assuming that since the BOM in the TGSL sticky post doesn't list the BF245 that the J107 was supposed to be used as its replacement, is that correct? Thanks again!

[ne555]

Transistor in my board 2n2907a/-331....2N2222A/H331...BC547B/166....BF245C/BB12... Ic is lf353n...lm393p....lm358p..lm308n...cd4024be...all r 1/4w and all c nf to pf 16to 50 v

[ne555]

Even without shielding does not give the desired depth I think the problem in the components of the board the problem not in shield

[kt315]

delete foil and do test again. you do not need shielding if your coil is stacionar.

[ne555]

https://youtu.be/YpnEfs3WGo4

[ne555]

Just i have 5cm depth for silver coin 10mm size my rx 6.4 mh and tx 5.9mh wair. 25mm whats proplem?

[yatahaze323]

Thanks again Nandor, I was unaware that the pinouts would be different I'll take a look at them and make the changes.

[Nandor]

Yatahaze pay attention to the transistors pins! I think that you have misplaced the Jfet J107 it's not BF245, it wont work that way!

[Nandor]

No problem
That resistor sets the gain of the filter and the cut off frequency and by changing the value from 4.7 to 5.1 has little effect.
4.7k-4.7uF=7.20Hz
5.1k-4.7uF=6.64Hz
Also those 10uF electric capacitors have a large tolerance rates of 20%. If you meaure them you can see that most of them have less than 10uF, 8.7uF or 9.2uF so using 2 back to back will not give you the nominal 4.7uF.
The most accurate choice would be using 1% 4.7k resistor with 5% 4.7uF polyprop caps and matched in pairs so each filter would have the value.

regards

[ne555]

Thank you for answer me

[Nandor]

Yatahaze after you make several units you wil know

Ne555, not so important you can use 4.7k or 5.1k without any noticeable difference!

[chevesne]

http://www.geotech1.com/forums/showt...257#post240257

[ne555]

Hi i have questions r13 and r14 = 5k1or4k7? I don't find file lay pleas any one have it

[yatahaze323]

Thank you Nandor! I appreciate your quick response!

[Nandor]

Hi
A1-A2=15nF or 4.7nF+10nF
A3=10pF
A4-A5=22nF
B1=Geb
B2=Sens
C2-C5-C3=Disc pot C2 is minimum Disc C3 is Max
C4-C1-C6= Disc Switch C4 Disc mode C6 All Metal Mode

Regards