Questions tagged [ferrite]

Anything related to the properties and applications of ferrites. Ferrites are ferrimagnetic compounds widely used in the manufacturing of electrical devices exploiting magnetic fields like inductors and transformers.

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Finding DC saturation behavior of clamp ferrites

While some chip ferrite datasheets specify maximum current and DC saturation behavior, it seems like many clamp ferrites omit both maximum current specification (which arguably is less critical) but ...
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Generating and measuring a sine wave with THD below -80dB

For an experiment I need to generate a sine wave which has a THD below -80dB. I would like to do that using a band-pass filter connected to a function generator because the output of the function ...
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Flashlight dismantle: why is a small cylinder of ferrite used?

After dismanteling a Petzl flashlight, I found a small cylinder of ferrite. Why is it used? For what? The flashlight used 3 AAA batteries so the ferrite bead doesn't seem to be used for reducing high-...
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Which frequency should be considered for inductor design in this FOT (fixed on time) PFC?

The PFC topology, I'm trying to design, works in transition mode, and switching frequency varies from 37 kHz to about 600 kHz according to the phase. The current flow through the inductor is as ...
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Will the current needed for core saturation (transformer) increase with applied voltage?

I was going through one of the research papers based on self-excited push-pull converters. The line below is taken from the paper: the current needed for core saturation rapidly increases with ...
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Ferrite rod (loopstick) antenna directivity

In a video about ferrite rod antennas it was stated that the antenna is most sensitive to the direction perpendicular to the axis of the rod, and it is insensitive along the axis. These are shown ...
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Why doesn't magnetic power transfer use ferromagnetic cores in the coils?

One well-known fact is that putting a ferromagnetic material in an inductor will increase the magnetic flux and thus the inductance value. Wireless power transfer (WPT) happens through the magnetic ...
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Ferrite on USB VBUS line for charging port

On USB host port (and usually on device ports, too) the VBUS line is filtered with a ferrite (Intel EMI Design Guidelines recommends a 500mA part, for example), and that is obviously fine for standard ...
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Burned component on GIGABYTE RTX 2080 GAMING OC 8G

I have purchased an RTX 2080 which contains a scorched component. I have carefully removed it with a heat station. The card is not short and it works, but it is seen with artifacts. As I found on the ...
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Which ferrite materials are used in GHz transformers?

Ferrite materials are commonly used for transformers for kHz and low MHz frequencies. Some vendors of RF products do however provide small transformers using small binocular cores (it looks like ...
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Current Density: Whether to calculate or use thumb rule in designing the ferrite core transformer

I am referring the book Transformer and Inductor Design Handbook[4E] by Colonel Wm.T.McLyman.In which he has emphasised to calculate the current density, rather than using the thumb rule value of 3-6 ...
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Split core vs. ring ferrite

I have an Arduino clone with L298P motor driver, which drives a linear actuator with a brushed DC motor and a built-in end of stroke mechanical switches and diodes. Motor runs at about 12V/2A DC, on/...
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GDT Core Selection for an MF Switching Action

I am designing an MF (approx. 1.5 MHz) MOSFET driver for an inverter circuit. I’d searched numerous driving strategies (according to the circuit’s needs like high frequency operation, drive-input ...
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Controlling motor EMI - more ferrite turns or shorter cables?

In wiring up a small robot, powered by two BLDC motors (of the "hoverboard" variety), I was going to shorten the leads a bit, and wrap them one turn around a soft-core ferrite for EMI ...
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2 votes
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What kind of inductor to choose?

Which kind of inductor should I choose if value is the same? rolled over a ferrite rolled over a plastic rolled in air rolled in a package looking like a resistor Is it related to specific roles? ...
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Possible Contradiction in N87 ferrite material μa vs B graph

Why does this graph description (of N87 material) states ^B =< 0.25mT (which is peak flux density), even though horizontal axis goes up to 0.40T? Is the horizontal axis in tesla peak-to-peak? Is it ...
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Ferrite core in electromagnets

I have a small project based around designing a small home-made DC actuator using a small DC electromagnet. My final goal is to generate the strongest magnetic field possible with the minimum amount ...
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Should I place ferrite barrel/ring on my Nokia 5110 module data lines?

I have Nokia 5110 LCD module from AliExpress. My motherboard is ruled by ATmega64A and control pins for LCD are grouped together as pin header (male, 8 pins in total). The module itself is placed on ...
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Magnetic circuit and material magnetization

We have a high power magnet (SmCo, 1T) whose field is being conducted through EN24T steel to an airgap where we perform measurements. The problem is that there appears to be a creeping change in field ...
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How can I noise decouple an FPGA with multiple VCC/VCCIO/VCCA pins?

Currently I am working on a small project using a Max10 FPGA from Intel. I know about decoupling IC using a capacitor in parallel and a ferrite in series. This works for a small amount of VCC pins. ...
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Is the necessity of the ferrite core on a PS2 controller cable a function of the length of the cable?

I'm connecting a wired PS2 controller to an ESP32. The controllers come with 2 meter cables that have ferrite cores at their connector end. I will be shortening to 5cm and soldering to a 5cm ribbon ...
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can somebody explain this sentence in better words?

what is the meaning of "reproducible Al values over time" and why should we need it to be reproducible over time??? and what is "production spread"?
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How to characterize a wideband RF ferrite transformer

Transformer models incorporating intrinsic and parasitic elements are well known: The mutual and leakage inductances are calculated from measurements of the primary and secondary winding inductances ...
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Where to get the core for an electromagnet?

I understand that using a soft iron core or a ferrite core for an electromagnet increases the strength compared to an air-core. I'm going to be using DC current and want the core to be 5-8mm in ...
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Multiple windings on single ferrite ring vs multiple ferrite rings

My question is does putting cables through multiple identical ferrite rings the same as winding them multiple times on a single ferrite ring? I have my current setup as follows with multiple ferrite ...
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3 answers
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Can a ferrite bead accidentally rectify RF?

If the ferrite is designed to filter out in the lower region, up to 100 MHz, and the pass-band signal is even way lower, 60Hz, I'm thinking that the ferrite is constantly saturated along with the 60Hz ...
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Difference between ferrite pipe core and full ferrite core?

Disclaimer: I’m computer scientist It is possible to buy ferrite pipe core coils and full ferrite core coils. The seller sell them for audio applications. I’m considering using the coil to measure a ...
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Short circuited ferrite bead on PCB

I'm analyzing a circuit (USB game console.) Three identical ferrite beads (805 or 603 package) are used in the circuit. It was working but I tried something on circuit. Now it is not working. I ...
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203 views

Loopstick (ferrite rod) antenna circuit model

A ferrite rod antenna circuit equivalent is usually given as so: The numbers are made up, I didn't calculate the exact C you need to have to make it resonate at 1 MHz. Here's a slightly more ...
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4 votes
3 answers
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EMC 30-50 MHz emssions

I was trying to pass EMC tests for my 48V 5A BLDC driver and failed in 30-50 MHz range. I think I found the problem in my drive circuit, but I have a few questions that got me thinking, maybe someone ...
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1 answer
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Why multiple coils on a ferrite rod antenna?

I'm trying to build some ferrite rod antennas to test some avalanche rescue technology and I've been looking at the internals of an old BCA Tracker avalanche beacon to figure out how I should go about ...
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Ferrite bead placement

I have a question regarding ferrite beads. I have this kind of circuit: Where IC1 and IC2 are digital ICs. The voltage supply for the opamps is obviously analog. I want to place a ferrite bead ...
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Ferrite underlay impact on chip antenna performance

I'm designing a small wireless chargeable IoT device which also has TX/RX in subGhz frequency (LoRa). The idea is to stack everything on top of each other starting with charger RX coil, then ferrite ...
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Ferrite Magnet as Ferrite Inductor Core?

I have a toroidal “ferrite” ceramic magnet lying around and am wondering what the similarities are (if any) between one of these that has been put in the oven to remove most of its magnetization and a ...
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The frequency rating of the snap ferrite

Snap on ferrites for power cables that are available on the the market are rated for frequencies varying from 1 to 300 MHz (most of them 100 MHz). I do not want any frequency to pass outside over my ...
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1 answer
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What is ferrite foil used for?

There is "ferrite foil" available on the market, often with self-adhesive layer on one side. What are typical use cases for this foil? How and where it is applied? I was surprised not to ...
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4 votes
5 answers
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Question on EMI filtering

I have seen people using ferrite beads to suppress EMI from switching power supplies. Recently, I came across the following blog post where the author successfully re-models a switching power supply ...
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3 votes
1 answer
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DC Inductor design for boost converter

I am working on the design and prototyping of a boost conductor. With that task in hand I have to design a DC inductor for a boost converter. I am using the material EPCOS N27 since its the only one ...
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2 votes
1 answer
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Core loss kW/cm³: UNFAMILIAR FACTOR

Looking at a datasheet picture, I assume this is an SI system value Pcv core loss kW/m³. I haven't found this mentioned in my studying material. What does it mean? Also, related question, how come in ...
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2 votes
1 answer
291 views

Please Identify this adjustable inductor (ferrite-core bobbin)

Can anyone identify this component and suggest where to get more of them---or provide a manufacturer/model number? I need more for an HF radio project but haven't found them. These are for hand-...
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Ferrite core StepUP Transformer Design

So, I want to make a High-Frequency Ferrite transformer that can convert my 150-volt peak Square wave into 100000 Volt Peak. I am using UUR6440 Ferrite Core. Material is CF139 https://www....
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6 votes
2 answers
1k views

How to compare a magnetic loop antenna to a conventional antenna

I want to build a compact 1 MHz receive coil (antenna for very near field). For that I need to make a choice on whether to build a simple RF coil only consisting of wire and capacitors or using a coil ...
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Gate drive transformer for lower frequency (25 kHz)

I am doing this half bridge to generate High voltage from 300VDC.(Around >10000Volts for a corona discharge tube to produce ozone) I have gone through many application notes for making one GDT for ...
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Inductor Core Material

I need to design an Inductor of 9.717μH to be used in a DC-DC Buck chopper for current of 10A. I finished the calculations using 3C94 core material. When I calculate the copper loss, it is 0.35W, and ...
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5 votes
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Ferrite rod antenna for DCF77 simulator

Where I live, in central Italy, the signal of DCF77 (the German longwave time signal and standard-frequency radio station, which operates at a frequency of 77.5 kHz) is so weak when it arrives, that ...
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1 vote
1 answer
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Is there an easy way to interface a receiving 457kHz ferrite rod antenna with a microcontroller (BeagleBone Black)?

I have a (actually two crisscrossed) 457kHz ferrite rod antenna from the internals of an avalanche beacon where 196uH <= L < 204uH and C = 560pF. I need to be able to evaluate the data from the ...
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3 votes
1 answer
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What material can I use to insulate NFC tags so they can be placed almost back to back?

I have posters with "Tap me to check in/out of this meeting room" drawn on them. I have NFC Stickers behind each poster to send the user to a specific URL in the application. They are being placed on ...
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10 votes
5 answers
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Why do toroid inductors have a square cross-section?

What is the reason behind the square cross-section of most toroid inductor cores? Correct me if I am wrong, but would not a circular cross-section give the lowest resistance since it has the smallest ...
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Calculating inductance of inductor that has ferrite core and a large air gap

I'm working on a coil on a PCB that will have a small ferrite core place in the center, with a large gap. I'm trying to come up with a decent equation to estimate the inductance of this inductor. I'...
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Comparing transformer set ups

Is it practical to connect the output of a ferrite-core 1:40 transformer in series with the input of a 1:6 ferrite-core transformer as a means of acquiring 240 V?What would the pitfalls be of this ...
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