Ferrite core is widely used component in electronic circuit. Working principle of ferrite core or ferrite bead will clear its importance in a circuit.
How do Ferrite Core Works?
• Ferrite suppress noise without ground. It didn’t discharge the noise to the ground.• When a wire pass through a ferrite core, it generates magnetic field.
• This magnetic field concentrate inside the ferrite core, and produce magnetic flux in the core.
• This magnetic energy is converted to the heat and it becomes magnetic loss of ferrite.
• Hence, noise is removed from the signal.
See below image to understand ferrite working;
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| How a Ferrite Works |
Placing a ferrite on both Signal and Ground
• We can place ferrite core on both signal and ground.• Common mode noise is in same direction so they don’t cancel each other. They are converted in magnetic flux and then to heat.
• Differential mode noise goes in through signal line and return back through ground line and hence cancels each other i.e. the current in the wire opposing to each other.
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| Placing a ferrite on both Signal and Ground |
Placement of an individual ferrite on Signal and individual ferrite on Ground
• Here an individual ferrite is placed on the signal and an individual ferrite on ground.• Common mode noise is in same direction so they don’t cancel each other. They are converted in magnetic flux and then to heat.
• In differential mode, this attachment is effective because the currents do not cancel each other. Noise is converted to magnetic flux and then to heat.
• Here as in differential mode no current cancels and if large current comes, then core will go in saturation.
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| Placement of a individual ferrite on Signal and individual ferrite on Ground |
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