On Apr 2, 9:42 pm, wrote:
Hi all,
I am student of engineering. I require inductors in nH range. But
m not able to find it out. Please tell me any site or place so that i
can get that in one or two days. Or if u hav any methode of makin
inductors please tell me.

It is not difficult to wind your own inductors. Values up to at least
a few hundred nanohenries may be made by winding copper wire around
the threads of a machine screw, and unscrewing the screw, leaving a
self-supporting coil. You have to be reasonably careful with such a
coil, but it's a practical way to wind small coils. For higher values
that require wire that's too fine to be self-supporting that way, you
can wind the coil on a ceramic or plastic form. PVC pipe isn't the
best RF insulator, but even it makes a decent coil form, and it's very
cheap and readily available in various sizes. You can find small
polystryene tubing at hobby stores, and it works well for a coil form,
too. The type they sell isn't high quality RF grade stock, but again,
it generally works well for coil forms. You can probably find other
plastic cylinders around your school that will work as coil forms.
You can even make your own by rolling up paper.

A good web site for calculating the inductance of a cylindrical helix
is http://hamwaves.com/antennas/inductance.html. There's an
inductance calculator for cylindrical helix coils and toroid coils in
the RFSim99 package which you should be able to find for free
download. It may well be useful to you for other things, too.

I assume these coils are for use at RF frequencies, probably a few MHz
or above, so winding them with solid wire is appropriate. Air-core
coils will have the best Q if you wind them with a little space
between the turns--pitch of the turns about 1.5 to 2 times the wire
diameter is usually good.

In the US, you can order inductors from DigiKey or Mouser and get them
quickly if you live close to where they are shipped from, or if you
pay extra for fast delivery.

Cheers,
Tom