Steve Anderson wrote:I'm kinda out of my knowledge base here. Correct me if I'm wrong (probably) but most metal detectors require the object to be at least partly Ferrous, containing Iron (e.g. Steel etc). Coins and the like are non-Ferrous, often Nickel, so how they work I'm not sure.
I'll have a look at the linked file and come back..
Steve A.
Yes so was i and still a bit to say the least ...
On Metal detectors its like Golf and different golf clubs you just about could used a different design for different soils and or what metals your looking for ....when you are talking the high end high dollars can do it all ..the rich get richer isn't it always the way !
OH no Steve Both ferrous and non ferrous ....i find it confusing too and again it depends on the metal detector design there must a fair few different types of metal detectors (golf clubs)
I used to think it was like radar its using the VLF type i wanted to try first
so at ULF and VLF you can transmit right through the earth so i thought well it hits metal and bounces back. its using radio waves ?
Well when i pointed that out i was told wrong boy its the magnetic field is inducing a magnetic field in the metal object which the metal object is sending back before its tiny induced field collapses which the coil receives.
I am told i need a PVC plastic the bottom section of my metal detector shaft even the brackets and bolts should be nylon or plastic .
The coils wrapped in foil which seems to increase the magnetic field ?
I am having problems with the simple floating ground works then doesn't i think i will just use 2 9 volt batteries this split rails driving me nuts .
I have the circuit going up to ic 6 pin 6 seeing the waveform and placing a metal object near the coil i can see a reaction on my little scope ,so this is a good thing ,i might as well hook the rest of it up see what happens .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.