Electric fields
1. An electric field can be present even when a device is switched off.
The higher the current, the greater Electric fields
Electric Fields
The higher the voltage the stronger the field produced. Since the voltage can exist even when no current is flowing, the appliance does not have to be turned on for an electric field to exist in the room surrounding it.
Magnetic fields
Magnetic fields are created only when the electric current flows. Magnetic fields and electric fields then exist together in the room environment. The greater the current the stronger the magnetic field. High voltages are used for the transmission and distribution of electricity whereas relatively low voltages are used in the home. The voltages used by power transmission equipment vary little from day to day, currents through a transmission line vary with power consumption.
Magnetic Fields strength is measured in amperes per meter (A/m). Commonly, EMF investigators use a related measure, flux density (in microtesla (µT) or millitesla (mT) instead.
AND
the devices tat used to detect is reveal on tis website
http://www.lessemf.com/dcgauss.htmlOne of them is the
HALL EFFECT SEMI-CONDUCTOR
Sensitive to Magnet Polarity
This component can be used in a circuit to open and close a contact when exposed to alternating N and S poles of a magnet. Will also work if exposed to the same pole on alternative sides of the sensor.
Many uses including:
Counting revolutions, oscillations, or sequences
Turning LEDs, alarms, or other devices on/off
Detecting presence of magnetized materialsIntruder/theft alarms
Monitor start/stop of a moving process
Robotic effects and magic tricks!
Schematic of an example circuit included. Part number may vary from picture. Very unique!
Hall Effect Semi-Conductor Sensor (Cat. #A402) …
$2.00 each This is the cheapest one tat looks like a conductor size tat allow u to solder it to a circuit board
there ar more devices there for u to view
Added on June 29, 2009, 10:46 pmQUOTE(cRazYee @ Jun 29 2009, 10:35 PM)
i think should be some magnetic stuff detect your battery ( this is what i heard)
Gratz, ur hypothesis is correct..
This post has been edited by Mizo: Jun 29 2009, 10:49 PM