Hi all, Just a thought, do any of you chaps know if the magnets in hi-fi speakers gradually lose there magnetic strength over time ? With my long-term magnetic...
I spent 25 years in pro audio. You don't need to worry about your permanent magnet speakers unless you beat them up physically. The earth's magnetic field ...
Hi John, Thnx for reply, yes i did quite alot of research lastnight on the good olde internet, i couldn't find any significant findings on magnets losing...
Hi John, Thnx for reply, yes i did quite alot of research lastnight on the good olde internet, i couldn't find any significant findings on magnets losing...
My magnetometer drifts all over-I assumed that it was measuring the earth's magnetic field drifting. Are you measuring something else? If you are using an ...
Hi John, I use a Philips KMZ(something, can't remember the number) dual sensor, i've managed to get rid of temperature drift & all voltages are steady. There...
New Magnetic Sensor 1000 times more sensitive than existing chip type. http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=202801602 Cheers...
New Magnetic Sensor 1000 times more sensitive than existing chip type. http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=202801602 Cheers...
Hello! I just joined, and am building the fatquarters' fgm-3 gradiometer kit with the intention of towing it behind a boat to look for shipwrecks. I am also...
USGS posted a new online strip chart display from many observatories: http://geomag.usgs.gov/realtime/ <http://geomag.usgs.gov/realtime/> Note that you can...
Hi: I have a number of very early electro-magnetic Toy DC Motors and would like to find out what the maximum drive voltage is that's useful. Measuring the ...
Ok...so do I understand this right...you have some old DC motors that you do not know what the operating voltage is on them...? I would say this, if I would be...
Alright then...do you have any idea of what the rated rpm is of them...? Even a good guess if there is nothing stated in them. Was thinking you could use a ...
Hi Island: Not really any idea about RPM. Also most of these were designed to run from No. 6 Dry Cells. It wasn't until I did the math on the Toy Motor Kit...
Did you say 17 Amps...???? That must have been one hell of a toy, and a hell of a battery as well! You mean 1.7 Amps...right..? ... Connect with friends from...
Hi Island: YES, SEVENTEEN amps. It was a suprise to me also. In the mid 1800s and early 1900s "Pocket Ampmeters" were popular. They were used to test the...
Hi: I'm working on making a Joule Thief (google it) which powers a white LED from a single cell. Since the LED needs much more than 1.2 or 1.5 volts a voltage...
... No, I don't think so. You are applying the rules of linear inductance to this nonlinear case. At saturation, the relative permeability of the saturated...
Hi John: Yes. I get it. At saturation there is no longer an increase in the field which is a change that causes voltage to be induced in other windings....
... But it doesn't collapse. it just continues to increase at a lower rate with respect to the current. Think of the saturated core material as a permanent...
Hi: I've been looking into how to choose the wire size and number of turns for a toroid core that I'd like to drive with less than a volt. My intution said ...
... turns for a ... intution said ... turn lowers ... number of ... Are you at all concerned about inductance or frequency, or only with DC effects resistance...
Hello good customers, we decided not to post this to the FQS website due to confusion resulting from similar messages in the past, such as when I was in the...
The way that I understand the soft iron can be compensated by rotational calibration. My question is how far can rotational compensate for the soft iron...
Hi John: It depends. Based on the theory I know. Suppose you made a polar plot, using the X and Y sensor outputs, by rotating the sensor assembly on a...
... I ... magnetic ... Typically soft-iron magnetic distortion will turn the XY circular plot of magnetic sensor outputs (arctan Y/X) into a tilted oval...
Hi: I got a dip needle and it does not seem to point like it should. I'm guessing that it's not as strong as when new. How to check that and magnetize if...
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