coil 100 uH with high quality

Question

Hi, I need a coil 100 uH with high quality ( Q parameter ). I would like to do LC circuit for frequency 500 kHz. AC and DC current is less than 1 mA. I have tried different coils and the results were very different. I think that the best was with round toroid. Is something in the Farnell cataloge what would be appropriate ? Thanks Fero

nickgray · Accepted Answer

You did not say just how small the current through the inductor, just how high you need the Q to be and what is the exact use of the coil. These are very important considerations. The current requirements should include both AC and DC currents. For high frequencies you probably want an inductor with a ferrite core.

One inductor of 100uH is the JW Miller type 3500-100K, which has a ferrite core, minimum Q of 39 at 796kHz and a saturation current of 800uA. Another 100uH inductor is the JW Miller type 73F-104AF with a ferrite core, minimum Q of 100 at 790kHz a saturation current of 800uA and a 7.7MHz self-resonant frequency.

For larger currents you might look at the API Delevan S4924-104K with a ferrite core, minimum Q of 50 at 2.5 MHz, saturation current of 113mA and a self-resonant frequency of 10MHz. The JW Miller type 9250-104 has a ferrite core, minimum Q of of 50 at 2.5 MHz, saturation current of 120mA and a self-resonant frequency of 10MHz. The JW Miller type 9250-104-RC has a ferrite core, minimum Q of of 50 at 2.5 MHz, saturation current of 160mA and a self-resonant frequency of 10MHz.

For information on selecting coils, I suggest looking at http://en.wikipedia.org/wiki/Inductor.

I hope this information is of some help to you.