This describes an easy yet reliable way to detect the intensity of a.c. or e.l.f. fields around the home or workplace. It is doubly effective because it does not merely detect the electromagnetic radiation emitted by electrical appliances, but the electromagnetic energy actually absorbed by the body.
The circuit in is a standard charge pump which is charged by the alternating eddy currents induced in the human body by a.c. fields. C1 charges virtually instantly, and is read by a digital (or high impedance) voltmeter.
To obtain a very rough translation from millivolts to milligauss (the unit of magnetic field strength), divide the millivolts reading by four. For example, 1000mV will yield 250 milligauss. A rough guide to the readings follows:
Up to 3 milligauss – Low electromagnetic radiation
25 milligauss – Significant electromagnetic radiation
100 milligauss – High electromagnetic radiation
250 milligauss – Maximum risk exposure
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