On 8/2/2010 1:36 PM, cagamba wrote:
Howdy. Here's a basic question about the labeling of inductors ...
Thanks
Marco
Marco,
The 224 is indeed 22 followed by four zeroes, or 220,000 of whatever unit the manufacturer decided to label the part with. Often that's nanoHenries.
You can tell at a glance which of nH (nanoHenries), uH (microHenries) or mH (milliHenries) a coil is by the number of turns and the wire diameter.
A coil with some number of nH is wound with just a few turns of wire. These are used at radio frequencies, over 30 MHz typically.
A coil with some number of uH is usually about the size of your fingertip and has many turns of wire, but the wire is big enough to see. These are used in switching power supplies at some hundreds of kHz. This is what you have, right?
A coil with a large number of mH is bigger than your thumb, and/or is wound with so many turns of fine wire that you can't see the wires individually. These are used at audio frequencies, such as speaker crossovers or telephone signal coils.
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David Forbes, Tucson, AZ
