Hello,

I am designing a simple oscillator in ltspice. It's working perflectly fine, now I need to build it. The inductor of the tank circuit is 8.2uH I was thinking if I could use a fixed inductor (or whatever it's called, see the image) or if I should just stick with an air coil. This oscillator will be used in a radio transmitter. What would be the pros and cons?

Thanks.

 

That picture is an air coil, an inductor with a core would be made of iron or ferrite dust.

 

Ok I am surprised. These inductors are available with values since 100nH to 1mH and they are all the same size. I would expect the size of the inductor to increase a lot with its value. I will try it and see what happens.

 

Hello,

The shown inductor is a fixed axial inductor.
The higher value inductors use a thinner wire, so the resistance is higher and the maximum allowed current lower.
I have attached two datasheets with this kind of inductors.

Bertus

 

Ok those have "ferrite DR core", it's what is in datasheet, but they are pretty good. I bought a kit of inductors from China (I am still waiting for them) but I bet they won't be that good. Meanwhile I bought PVC to make an air coil inductor, I will use both inductors and compare the results.

 

Hello,

If you want to make air coils, the following page will give you a lot of information on them:
http://info.ee.surrey.ac.uk/Workshop/advice/coils/air_coils.html

This is one of the links of the EDUCYPEDIA page on coils:
http://educypedia.karadimov.info/electronics/coilsrelay.htm

Bertus