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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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7 votes
2 answers
416 views

Inductance after core saturation

Looking at the datasheets of some drum core inductors, at higher currents the inductance drops significantly due to ferrite core saturation. But it seems inductance asymptotically approaches a value ...
ac47's user avatar
  • 71
4 votes
1 answer
108 views

Calculating Core Loss Coefficient (Kfe) for Ferrite Materials

I'm having trouble calculating the core loss coefficient Kfe for ferrite materials. I'm referencing Chapter 15 of "Fundamentals of Power Electronics" by Robert W. Erickson and Dragan ...
Hector's user avatar
  • 403
1 vote
3 answers
106 views

Kapton instead of air gap (ferrite core)

I'm working on a flyback converter topology and I want to create a 1 mm air gap in the ferrite core transformer in order to decrease AL. I didn't find one with air gape, I heard of a solution that is ...
Noureddine Bimgdi's user avatar
0 votes
2 answers
170 views

High magnetic permeability material at 100MHz

I'm doing experiments as a hobby and was trying to find a material with good (very good) magnetic permeability at least at 100 MHz (higher frequencies are even better). Ideally the material would have ...
mabeco's user avatar
  • 95
1 vote
1 answer
131 views

4-20mA ferrite bead position

I have done EMC radiated immunity testing on 4-20 mA analog inputs and I noticed bad reading on these inputs when sweeping around 600-800 MHz at 5 cm at 100 V/m (antenna method). To improve the noise ...
JeanB_01's user avatar
0 votes
1 answer
63 views

Understand ferrite core effect - How to derive its common mode impedance?

I would like to understand the "mechanics" of a ferrite core. Id like to know how it blocks common mode currents when placed on a cable with multiple wires. I know that the ferrite, placed ...
stowoda's user avatar
  • 582
0 votes
0 answers
68 views

Oring Diodes: is RC discharge circuit needed for prevent disconnection issue?

I have a new design implemented with oring diodes circuit as shown in picture below, where I have POE_VIN_24V coming from POE+ Module, and PHNX_DC_IN coming from phoenix connector, that is connected ...
Firas Abd El Gani's user avatar
4 votes
2 answers
149 views

Why does the Inductance change on an E-Core Leg when going from Small Copper Wire to Litz Wire?

In the first picture you can see 45 turns of standard 0.4 mm copper wire. The impedance analyzer (e4990) shows an inductance at 20 kHz of 11.5 mH. Which is inside the tolerance of around 12.8 mH +- 20%...
cu 29p's user avatar
  • 71
1 vote
0 answers
93 views

How do you simulate a ferrite clamp in LT Spice?

Someone asked before how to get parameters for ferrite bead simulation. The same method doesn't really work for clamps because almost all of them don't give information about resistance. I began ...
Tony's user avatar
  • 187
1 vote
2 answers
88 views

Ferrite Loopstick Antenna Grounding

I've built a simple tuned frequency radio based a description in Ronald Quan's book. I have two questions about the tuning part of the circuit. The radio has a ferrite core antenna with two separate ...
M. Enns's user avatar
  • 113
0 votes
1 answer
104 views

Ferrite cores ANSYS MAXWELL - where to find more BP curves?

i need more than one BP curve (for different freq.) for loss estimation. But in datasheet there is for only one frequency, so dont know how to solve this? Without mailing distributor, that will be ...
LinejHonzaCZ's user avatar
2 votes
0 answers
244 views

Can I put ferrite cores around the romex in my electrical boxes and breaker panel? [closed]

I've recently replaced most of the breakers in my house with dual-function arc fault/ground fault protection. (I spent five years in forensics, I'm deeply paranoid, don't judge me.) Naturally I'm ...
Stephen Collings's user avatar
2 votes
3 answers
272 views

Ferrite bead value for a LIN bus protection circuit

What is the proper value for FB1 in relation to the surrounding capacitors in this diagram? The FB1 resistance is measured to 0.76ohm and package size is 0603. All components are AEC-Q200 rated. The ...
ajdalshov's user avatar
0 votes
1 answer
140 views

What is this black thing on my mouse's cable? Is it related to the mouse not working? [closed]

I was curious so I got an old mouse that doesn't work and decided to try and fix it. I got it open and tested the four wires coming from the cable with a multimeter but nothing anywhere. I thought ...
Keyboard's_Slave's user avatar
4 votes
1 answer
183 views

Boost Inductor Design for three phase Diode Bridge Rectifier for PFC operation

I am doing a simple DCM based control for power factor correction. Please see the topology below . Specifications are as below: 1.) Power 5KW 2.) Input Voltage is 415V L-L Nominal 3.) Inductor ...
Archit Asthana's user avatar
2 votes
0 answers
85 views

Derivation of formula for transformer maximum power

How can I derive the formula for the maximum power handling of a HF transformer with ferrite core utilized in a selected converter topology (push-pull for me). The formulas I have seen so far utilize: ...
andi8086's user avatar
  • 143
1 vote
1 answer
116 views

Ferrite cable core selection best practices for USB 2.0 Full Speed

From signal integrity and best possible EMI suppression perspective should ferrite cable core match the characteristic differential impedance of 90ohms @ 12MHz (for USB 2.0 Full Speed) in order to ...
almnk's user avatar
  • 23
2 votes
1 answer
1k views

How can I calculate the size of a power ferrite core transformer?

I'm working on an amplifier that has to drive a load with 200 W at 100 kHz. I have a tested architecture based on wideband ferrite transformers but for 50 W and higher frequency. My goal is to ...
mtx4's user avatar
  • 91
6 votes
4 answers
1k views

Value of a ferrite bead in PHYs

I have seen a couple of ethernet PHYs whose manufacturer datasheet recommends placing a ferrite bead on the power supply input of the PHY device whose value is, "Generally, a 100-220Ω (at 100 MHz)...
Freshman's user avatar
1 vote
1 answer
48 views

What does float long and float short mean with respect to ferrite core transformer windings? [closed]

I have winding instructions for winding a EE13-06 ferrite core transformer, for secondary it's written 0.23 mm TIW, no. of wire = 1, no. of turns = 66, start = float short, finish = float long. What ...
Yogita Adhikari's user avatar
0 votes
4 answers
555 views

AM Receiver Antenna Coil

In almost all the radio receivers whether FM or AM, custom wire-wound coils are used that are wrapped on a ferrite core usually (not always) of 100 mm x 10 mm dimensions. Is it possible to use fixed ...
Awais Mushtaq's user avatar
1 vote
1 answer
213 views

Push-pull converter: ferrite core transformer dropping voltage [closed]

I am creating a 100 W, 12 V to 120 VAC @50hz inverter. I have implemented a push-pull converter to obtain a 200 VDC link for the H-bridge of the inverter. I am having problems with the push-pull ...
Darren Millington's user avatar
1 vote
1 answer
53 views

Effects of ferrite isolator on waveform

I have recently measured the standing wave signal from a waveguide. I notice that as the frequency is lowered the signal tends towards a sawtooth wave. ** My guess for why this happens is that the EM ...
dk30's user avatar
  • 11
0 votes
1 answer
347 views

High PWM frequency step-up transformer using PWM signal generator and MOSFETs

I am trying to build a high frequency step-up transformer for PWM signals. The signal that I want to step-up with transformer has to be modifiable with the 2 pulse signal generators. So Freq 1 and ...
Javiero's user avatar
1 vote
1 answer
840 views

Should I use a ferrite core on my AC adapter? [closed]

I'm using an AC adapter for a port replicator (it meets the voltage and provides more amps) which doesn't have the ferrite core the original one had. Should I put one of these ferrite cores on it or ...
const314159's user avatar
4 votes
3 answers
5k views

USB 2.0 VBUS Filter

I am reading an old (2013) FTDI application note AN_146 about hardware design for USB 2.0. On the subject of VBUS filtering, it says this: 2.4.4 Ferrite bead use and placement – USB peripheral ...
jemalloc's user avatar
  • 720
0 votes
3 answers
610 views

Value of ferrite bead while connection chassis ground (from RJ-45 connector) to digital ground

I am connecting the chassis ground of the RJ-45 connector to the board's digital ground. In that case, I saw an Evaluation board design that uses a 1000pF 2kV cap to connect both the grounds. My ...
user avatar
1 vote
0 answers
138 views

How to increase output current while maintaining low voltage through a ferrite transformer?

I'm building a circuit to generate a 4600 Hz square wave signal and couple that signal to household 120 V, 60 Hz AC mains. This remotely turns on and off a receiver device plugged into an outlet in ...
Dewster's user avatar
  • 11
0 votes
2 answers
79 views

MC34063A ferrite bead

The converter works in the inverter mode and gives an output of -5V. I present a diagram based on the documentation. I want to eliminate the output voltage ripple with a ferrite bead. Unfortunately, I ...
grandzello's user avatar
0 votes
1 answer
191 views

How to measure the leakage inductance of LLC Split bobbin transformer with two auxiliary windings

Let’s say I am having ETD core and split bobbin for LLC Design I have 4 windings in that transformer primary secondary primary aux secondary aux I am winding the primary and primary aux windings in ...
Venkatesh's user avatar
0 votes
1 answer
1k views

Confused about which impedence value to pick for ferrite bead

Per the vendor's recommendation, I need to add a ferrite bead to the 2.5 V power supply. An evaluation board used the BLM31PG601SN1. It has an impedance of 600 Ω at 100 MHz and a rated current of 1500 ...
Matty's user avatar
  • 217
5 votes
1 answer
2k views

Is this a good idea to separate Grounds via ferrite beads?

is this a good idea to separate the GND of different parts of a circuit trough Ferrite Beads? I have different parts in my board: 1- Microcontroller unit 2- Digital Inputs 3- Digital Outputs 4- Analog ...
Eric Matevosian's user avatar
9 votes
5 answers
3k views

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 ...
Shannon's user avatar
  • 379
0 votes
1 answer
178 views

Issues Choosing Flyback Transformer Specs & General Direction Help

I'm working on trying to figure out how to wind transformers myself and picking values etc. I currently have PQ26/25 Bobbins with PC95PQ26/25Z-12 ferrite cores (N95). I have some smaller E cores ...
jonny5556's user avatar
0 votes
1 answer
149 views

determining the Bmax for inductor design

at this moment of this youtube video following graph is presented for selecting the proper maximum flux density. the considered proper amount of core loss is 100mW/cm^3. is this a general amount for ...
WeTech's user avatar
  • 735
2 votes
1 answer
809 views

What are the differences between these ferrite cores?

The ER, EC, and ETD ferrite cores are presented in a datasheet but visually I don't see any difference between them. The search results also say the same thing.
WeTech's user avatar
  • 735
0 votes
1 answer
98 views

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 ...
NoobPointerException's user avatar
2 votes
2 answers
306 views

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 ...
Mantabit's user avatar
  • 343
1 vote
0 answers
138 views

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-...
MagTun's user avatar
  • 251
4 votes
1 answer
269 views

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 ...
WeTech's user avatar
  • 735
1 vote
2 answers
759 views

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 ...
sarath's user avatar
  • 11
1 vote
1 answer
816 views

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 ...
Horror Vacui's user avatar
  • 1,397
3 votes
3 answers
457 views

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 ...
Horror Vacui's user avatar
  • 1,397
2 votes
1 answer
953 views

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 ...
Lorenzo Marcantonio's user avatar
1 vote
1 answer
208 views

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 ...
Expoespa's user avatar
2 votes
2 answers
952 views

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 ...
rubund's user avatar
  • 141
0 votes
1 answer
538 views

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 ...
Israr's user avatar
  • 249
0 votes
2 answers
147 views

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/...
Paul Jurczak's user avatar
0 votes
0 answers
64 views

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 ...
Karakoncolos's user avatar
0 votes
0 answers
291 views

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 ...
Jake Poznanski's user avatar