What effect does the black bureau on the laptop charger cord have?

Near the end of the laptop charging cord there is a black cylinder called a ferrite bead, which is responsible for blocking electromagnetic interference from a device and to a device.

Just like an antenna, a transmission cable will transmit radio frequency energy generated from the device. And then, ferrite bead will help minimize electromagnetic interference. If there are sources of electromagnetic interference emitted from other devices, ferrite bead will be responsible for preventing the cable from transmitting this interference to the target device.

For example, when you connect a phone to the computer, this process will produce electromagnetic interference and without ferrite bead, you may not be able to use the device by the screen of they may be flashing.

In summary, ferrite bead is responsible for intercepting electromagnetic interference to ensure the signal is exchanged only in a reasonable direction and for the right purpose. And the position at the end of each cable is the best position for ferrite bead to complete its mission well.

In addition to the large ferrite bead, which is placed on the strands, we still see that there are many other ferrite bead inside the device. For example, the ferrite bead is placed on the circuit board inside the device.

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