A ferrite bead is a passive electric component that suppresses high frequency noise in electronic circuits.

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How to calculate EMI filter (ferrite bead) specs for digital signal?

I have a small project of mine that deals with plain old VGA output (d-sub). In my project I'm using a CM2009 IC between actual VGA controller and VGA output connector. It's mentioned in the datasheet ...
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773 views

What is the component on the schematic indicated by the symbol of a diagonal rectangle with a line through it?

I can't for the life of me, figure out what these diagonal rectangles are... Help?
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435 views

What's the purpose of a ferrite bead inductor on an analog voltage reference 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). ...
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82 views

Ferrite Bead Current Rating

Could anyone let me know how can I calculate the current rating required for a ferrite bead on speaker path? The speaker impedance is 32 ohms.
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105 views

What does 100Ohm @ 100MHz exactly mean in ferrite beads?

I am trying to understand the parameters of ferrite beads and having trouble in understanding the impedance vs frequency parameter. What does 100Ohm at 100MHz exactly mean? Does it mean that the ...
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120 views

EMI suppression low frequency

I'm dealing with a PWM generator which drives a load at 12V with pretty high currents (5-10A) The PWM frequency is in the band of 100-200 Hz. Which is the best choice and right configuration of ...
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943 views

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 ...
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121 views

Using Ferrite bead and common mode choke in series

I would like to use ferrite beads and a common mode choke on the same line. The circuit will be doing power line communication so I would like to use common mode choke in order to block out common ...
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191 views

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?
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234 views

Can smd ferrite beads be avoided [closed]

I am redesigning an input interface circuit for digital input. Its a basic signal conditioning circuit for reverse polarity protection, EMI ESD protection, and filtering voltage surges. For EMI EMC, ...
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434 views

Fighting overshoots/undershoots using ferrite beads does not help?

I posted relative problem a while ago here but we came to conclusion that the overshoots were just artifacts. Later, when I extended the signal lines, the overshoots increased and were about 2V of ...
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211 views

Why does this low-cost battery powered device use ferrite beads on the power input?

I have just opened up a small, low-cost motion-activated (by PIR) LED light as I am planning on just using the casing for another project. The PCB inside is clearly designed to be very cheap. It uses ...
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348 views

Where to connect shield and ferrites in PCB with isolated planes

I have a device which has two sections of the PCB completely isolated form each other, but connected by an isolator IC (PN: ????). I think I need to shield the whole device for reducing EMI because ...
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760 views

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 ...
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114 views

Different voltages with Ferrite Beads

I am checking the datasheet of one complex component, and the schematics of one demo board, and I find a difference that I would like to ask here. It is a 100Base-tx switch. The chip uses 3.3v for ...
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419 views

Ferrite Bead Simulation in SPICE

I am reading this link about ferrite beads and in page 2, figure 2, there is a SPICE circuit to emulate the ferrite beads frequency response. Why there is an AC Current Source in the circuit? Why ...
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222 views

Ferrite Beads - Maximum DC current and resistance

I'm building a PupDAC (http://www.diyforums.org/PupDAC) and am looking into two different Ferrite beads. The plan for the PupDAC calls for this Vishay/Dale model (link 1) while I'm looking into this ...
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542 views

Ferrite bead for use for filtering a microSD card's Vcc

I am hoping to use a microSD card in an AVR project and am just trying to find values for all my components. However, I am not sure what value of ferrite to use here. The few microSD schematics that ...
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413 views

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 ...
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1k views

Ferrite beads in Quasi-Resonant Switch-Mode Power Supply (QRSMPS) primary?

I am using the Fairchild FSCQ series and I am shocked that nowhere is there any guide for sizing the bead on the drain. The frequency range is 24kHz min. to (looks like) 90kHz. There is also another ...
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3k views

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?
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156 views

How can I identify ferrite bead material?

I am working my way through the book "The Electronics of Radio" by David B Rutledge", which details experiments on the various parts of the circuit as one builds a "Norcal 40A" transceiver, as a ...
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218 views

Magnetic core transfer loops (logic)

I have an interest in "alternative" logic gates, as in not silicon transistors. I have built RAM in a little game called "Powder Game", constructed "one-off" logic gates out of exploding lattices of ...
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572 views

What is the effect of Saturation on a Ferrite Bead Inductor?

This circuit shows the "current channel" of an energy meter. IA_IN are the two inputs for a shunt (typically 250 uOhms) while TP1 is the connection to the energy measurement IC, which uses the 3.3 ...
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903 views

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?
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126 views

Surface mount bead core

I am experimenting with surface mount components for a project. All the other components seem to be OK and I have deduced that it is the surface mount bead core that is the problem. When I remove ...
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945 views

How use ferrite bead to reducing noise from charge pump?

Old senior design project and in schematic I see he uses ferrite bead and capacitor after charge pump voltage output befor connecting to opamp input Circuit very simple: charge pump uses MAX232 to ...