sinaghahhari نوشته است:
سلام خدمت دوستان یک مگنومتری دیدم انگار کمی جالب بود برای همین قرار می دهم در اینجا تا سروران گرامی نظر خودشان را بدهند
این لینکش
http://motivationtolearn.org/wordpress/?p=1347DIY fluxgate magnetometer for experimenters
I don’t think I’ve ever made anything with such an impressive-sounding name before. Doesn’t it sound like something out of a sci-fi movie?
I didn’t make this as a project for my students – it’s a bit advanced. Rather I made it as part of my ongoing quest to record electromagnetic earthquake precursors: one of the ways in which they might be observed is by recording small changes in the Earth’s magnetic field. Thus my interest in magnetometers.
I recorded data from my search coil magnetometer for many months, but it was subject to a lot of interference in my location and, by its nature, could only record short pulses, not long duration changes. Then I set up my milk bottle magnetometer which has been happily recording for a couple of years, but it was a delicate job to position it and was sensitive to physical vibration (it made a pretty good seismometer.)
The fluxgate on the other hand is easy to position and records any changes that can be observed at 3 samples per second. Another significant difference is that it also responds to changes in the strength of the field, whereas the magnet-in-a-milk-bottle only records changes in the direction. Sometimes this will equate to a similar reading but not always. So now I see quite consistent correlation with other magnetometers in this part of the world (I’m in Taiwan). It is definitely showing solar phenomena, especially in the middle of the night when it’s not obscured by so much local interference such as passing buses etc.
Here is a recent 24 hour trace plotted, for comparison, underneath the trace from an Intermagnet magnetometer in Vietnam. This trace was of special interest because it contained a large dip just prior to a 6.1 earthquake in the middle of Taiwan. It appears not to be solar phenomena since it didn’t appear on the trace in Vietnam. I’m not sure what to make of it yet as this was only in the first few days of recording with this device