In the May 2007 issue (No.365) an article describes a magnetometer using an unmodified mains transformer as the sensor.
I would have thought that the closed magnetic circuit would tend to cancel out changes in the induced voltage due to a varying external field. Probably not perfectly, but still...
I'd be interested in the opinion of the experts.
All the best Ian Macmillan
Ian Macmillan a écrit :
Don't have the article, but the general way of doing this is by alternatively saturating or not the core. In the unsaturated state, the core will divert the external flux line from the coil, while in the saturated state these external flux line can reach the measuring coil.
Anyway I can see how to use a mains transformer for this, but certainly not unmodified. Can you post a scan?
-- Thanks, Fred.
an
cancel
Probably
The circuit simply connects the windings of the transformer in series to the differential inputs of a LM380 without any bias current in the coil.
Years ago I made a DC ammeter using the principle you mention in a ferrite core to vary the MS ratio of a multivibrator.
All the best Ian Macmillan
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