Faraday Cage - Examples

Examples

• A microwave oven is an example of an inside out Faraday cage, keeping the RF energy within the cage rather than keeping it out.
• Elevators and other rooms with metallic conducting frames famously simulate a Faraday cage effect, leading to a loss of signal and "dead zones" for users of cellular phones, radios, and other electronic devices that require electromagnetic external signals. Small, physical Faraday cages are used by electronics engineers during testing to simulate such an environment in order to make sure that the device gracefully handles these conditions.
• The shield of a screened cable, such as USB cables or the coaxial cable used for cable television, protects the internal conductors from external electrical noise and prevents the RF signals from leaking out.
• A booster bag (shopping bag lined with aluminium foil) acts as a Faraday cage. It is often used by shoplifters to steal RFID-tagged items.

• Plastic bags are included with electronic toll collection devices which are impregnated with metal to allow motorists to place them in the bag so that a toll charge is not registered or a device will not register a charge while being shipped to a customer's home after ordering in a delivery truck.
• Some electrical linemen wear Faraday suits, which allow them to work on live, high voltage power lines without risk of electrocution. The suit prevents electrical current from flowing through the body, and has no theoretical voltage limit. Linemen have successfully worked even the highest voltage (Kazakhstan's Ekibastuz–Kokshetau line 1150 kV) lines safely.
• The scan room of a Magnetic Resonance Imaging (MRI) machine is designed as a Faraday cage. This prevents external RF (radio frequency) signals from being added to data collected from the patient, which would affect the resulting image. Radiographers are trained to identify the characteristic artifacts created on images should the Faraday cage be damaged.
• Faraday cages are routinely used in analytical chemistry to reduce noise while making sensitive measurements. A home-made Faraday cage used for simultaneous microscopy and electrochemistry is shown to the right.