Why cables are shielded or screened
Cables are shielded or screened to protect the signals that are transmitted through them from external electromagnetic interference (EMI) and radio frequency interference (RFI). This interference can come from various sources such as power lines, electronics, radio waves, or other cables running nearby.
Shielding or screening helps to minimize the impact of this interference on the signal quality, ensuring reliable and accurate transmission. It acts as a barrier to block or reduce the penetration of external electromagnetic fields into the cable, preventing them from interfering with the signal.
There are different types of shielding used in cables, such as foil shielding, braided shielding, or metal-coated shielding. These shielding methods create a grounded barrier around the signal-carrying conductors, creating a shield that reflects or absorbs external electromagnetic fields.
By using shielded or screened cables, the risk of signal degradation or loss due to interference is greatly reduced, resulting in better signal integrity, reduced noise, and improved overall performance of the cable. This is particularly important in sensitive applications like data transmission (Ethernet, USB), audio/video signals, telecommunication, medical equipment, and industrial control systems, where reliable signal transmission is crucial.