This circuit is provide 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. This is the figure of the circuit;
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 milli volts to milli gauss (the unit of magnetic field strength), divide the milli volts reading by four. For example, 1000mV will yield 250 milli gauss.
