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

[Qiaozhi]

How do you calculate coil?

Coil Calculator

[marin2]

With lm318 i always had
500 840 840

[cvele]

No, it cannot be!
May be 320 350 390. In that case lf357 is fake.

[marin2]

to Cvele
debug numbers
A 32 B 35 C 39

[cvele]

to marin2
there are a lot of coil calculators online, just go to google and try (coil calculator), I am a little bit confused with Your debug numbers.
What are they exactly? a=? b=? c=? (300, 700, 800 - optimum)

[marin2]

thank you very much cvele
How do you calculate coil?
I have decreased to 24 turns
But it's always better 37 37 45
Detection coin of diameter 3 cm to 14 cm

[cvele]

Hi marin2
inductance of Your coil is too high 591uH, Try with 25 turns and if not good enough, go to 24, lf357 looks ok but do not use holders for transistor, just solder it directly on PCB.
A little bit more about coil - try some other tips (basket or spider), there are a lot of examples on geo.
regard

[marin2]

Here the coil 27 round diameter 28 cm
Wire diameter 0.7 mm
And voila 357 is it original ????

[karim1980]

ici 357 is not original

[lc516]

Hello everybody
I always have low values
A: Almost B : 30 nearly C : 40 almost 100

You can show your coil

[marin2]

Hello everybody
I always have low values
A: Almost B : 30 nearly C : 40 almost 100

[smit22]

[cvele]

and:

[cvele]

Nice work smit22!
I prefer small (20 to 25cm) coil and use manual set up for delay, usually around 20, and spider kind of, because it is easy for me to set it up.
Here are some pics of 25cm coil I just made and as You can notice wires are not soldered yet so a)300 b)688 c)784 will come in place after soldering and
making all rigid.

[smit22]

Https://www.youtube.com/watch?v=UxttKqLFC4o