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Questions tagged [ferrite-bead]

A ferrite bead is a passive electric component, which is commonly used for suppressing high frequency noise in electronic circuits.

A ferrite bead is a passive electric component, which is commonly used for suppressing high frequency noise in electronic circuits.

enter image description here
(a) Simplified circuit model
(b) Tyco Electronics BMB2A1000LN2 measured ZRX plot
source: Analog Devices article Ferrite Beads Demystified

131 questions
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Ferrite bead vs common mode choke

simulate this circuit – Schematic created using CircuitLab I inherited the top circuit from a previous designer on my robotics team. The circuit uses two ferrite beads, a zener, a TVS and a capacitor to filter incoming power. The incoming power…
vini_i
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Ferrite bead position

I wish to use some extra power supply filtering for my DAC, ADC, CPLD and OpAmp devices. In this question I got the point about the global locations for ferrite beads. If I understood correctly, the ferrite bead should be placed close to the device…
Nazar
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Why not use a ferrite bead around an RS-232 cable?

This is from the instruction manual of a printer: As you can see, one is not supposed to wrap the supplied bead around the serial cable. What is the reason for this?
AndreKR
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How to select a good Ferrite Bead

I am building a USB project and I want to use a Ferrite Bead in the USB 5V rail. I am looking for 1206 Ferrite Beads. How to select them properly? Which impedance at 100MHz is a good one?
mFeinstein
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EMI Filtering on LVDS lines

This question is slightly related to: What's radiating on my PCB? These are Beckhoff's EtherCAT industrial IO modules. Each module is connected to its neighbours by 100mbps LVDS. Each module contains an ET1200 ASIC which handles all of the…
Rocketmagnet
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North American standard symbol for ferrite bead?

Many of the schematics I've seen in reference schematics use an the symbol of an inductor as the symbol for a ferrite bead (makes sense). But I've also seen other variants of it as well. I don't have the IEEE 315 document, but I know that there are…
efox29
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How do I choose a ferite bead for power supply filtering?

I want to put a ferite bead on positive SMPS supply rail that goes to analog part of the mixed digital/analog circuit. Now on parametric search at Digikey I can see several parameters: Current rating, DC resistance, Impedance @ frequency. I…
miceuz
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Does the position of the Ferrite bead matter?

Often I will see a ferrite bead a couple of inches from one end of a cable. Does the position of a ferrite bead really matter?
Scott
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Ferrite bead selection

In some pages online, it is mentioned that "whenever possible, the targeted noise frequencies should fall within the bead’s “resistive band,” meaning the range of frequencies in which the resistive impedance dominates the reactive impedance." Does…
Shannon
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What's the purpose of a ferrite bead inductor on this circuit?

I'm studying the analog voltage reference circuit described in the AVR450 Application Note - Battery Charger for SLA, NiCd, NiMH and Li-Ion Batteries, which schematic is below (copied from page 38). On page 40, there's a schematic showing the MCU…
Ricardo
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Ferrite instead of LDO

Currently we are using the following power supply scheme: This solution effectively separates the analog sub-part of the PCB from the noise of the digital sub-part. Now we are going to use the following scheme: The main benefit is decreasing the…
user3583807
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What frequency is Ferrite Bead reactance usually given at?

I've noticed on schematics at work, when I was at uni, and on datasheets that Ferrite Beads usually (90% of the time) are only given with their designator (FB? or L?), then the reactance (XOhms) and the current rating (1.5A for example). However,…
DSWG
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When has to be used a ferrite bead in power supply?

I'm designing a PCB with a Telit GL865 GSM/GPRS module. I find this example in Internet and I am wondering why has it got a ferrite bead on 3.3V power supply line. Some extre values from datasheet: Vin between 3.22V and 4.5V (Extended mode) and…
ferdepe
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Regarding Ferrite Bead

What is a ferrite bead? How is it different from an inductor? How is it rated? What are its important parameters? What allows me to chose between an inductor or ferrite bead to filter out frequencies that are greater than 8 kHz in a signal with a…
Naveen
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Cable wrapped around a ring in electronic device: how to remove it?

On an electronic typewriter, a display cable wraps around a ring. What is it for and is there a way to remove (break) that ring in order to extend the cable length?
JeanB
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