Description:
The circuit of Fig.1 provides 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.
Fig. 1
The circuit in Fig.1 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
mill volts reading by four. For example, 1000mV will yield
250 mill gauss. A rough guide to the readings follows:
Up to 3 milligauss - Low electromagnetic radiation
Detrimental effects have been reported at doses as low as 3
milligauss, and a series of studies since the 1970's has
shown that sustained exposure to high e.l.f. doses heightens
the risk of certain cancers and miscarriage.
Readings are taken while holding the probe in one hand. The
closest proximity to the electromagnetic source does not
necessarily give the highest reading, probably because the
induced currents in the body remain localised at close
proximity.
The Sensor
Is any piece of metal (e.g. a short stub of copper piping,
even a short piece of fencing wire) that makes good contact
with the hand.
