Frequently asked questions
Short answers about ferrite cores, iron powder cores, EMI filters and the quote process. If you can't find your question, ask us directly.
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Technical questions
What is a ferrite core?
A ferrite core is a part made of a ceramic magnetic material that carries the magnetic flux in inductors, transformers and interference suppression components. Because it is a ceramic, it is brittle and sensitive to shock, fast temperature changes and tensile load. Mechanical stress in the core also affects its magnetic properties.
More information →Source: TDK: Ferrite core data and cautions
What is the difference between MnZn and NiZn ferrite?
They are different ferrite material families that work in different frequency ranges. High-permeability materials are effective at lower frequencies and lower-permeability materials at higher frequencies. For interference suppression, MnZn materials are mainly used against conducted noise and NiZn materials against radiated noise. The effect also depends on core shape, size and number of turns, and should be tested on the actual device.
How to choose a cable ferrite: diameter, frequency and installation →Source: KEMET: Ferrite material and frequency range
What is the AL value of a core?
The AL value (inductance factor) gives the inductance per turn squared for a core set and is stated in nH/turns². Inductance is approximately L = AL × N², where N is the number of turns. The AL value applies to a specific set, air gap and test condition, so read it together with its tolerance and the set it refers to.
How to choose an EE ferrite core: EE25 and EE42 replacement checks →Source: Ferroxcube: U25/20/13 inductance factor
Why is an air gap used in a core?
In inductors and flyback transformers, almost all of the energy is stored in the air gap; the high-permeability core provides an easy flux path that links this energy to the winding. The gap lowers the effective permeability and sets how much energy the core can store. Fringing flux outside the gap can cause extra losses and an inductance different from the expected value.
ETD29, ETD39 or ETD44: how to choose a ferrite core for an SMPS →Source: Texas Instruments: Inductor and flyback transformer design
What is a current-compensated (common-mode) choke?
It is a choke with two windings on the same core, used to suppress common-mode interference on mains lines. The operating current flows through the two windings in opposite directions, so their magnetic effects largely cancel and the core is not saturated by that current. Common-mode noise flowing in the same direction on both lines meets a high impedance. These chokes can be built on ring, U, D or frame cores.
How to choose a single-phase EMI filter: current, leakage and installation →Source: TDK: Power line chokes
From the technical guides
Is a cable ferrite the same as a PCB ferrite bead?
Both can suppress interference, but their mechanical construction and application differ. A core fitted around a cable should not be recommended as a direct replacement for a ferrite bead soldered to a PCB. This guide covers cable-mounted products.
How to choose a cable ferrite: diameter, frequency and installation →
Is the cable diameter enough to select a part?
Diameter narrows the mechanical candidates. Electrical suitability cannot be confirmed without frequency and application information. Describe the device and the observed problem as well as the cable dimensions.
How to choose a cable ferrite: diameter, frequency and installation →
Can I use ETD39 instead of ETD29?
Do not assume a direct replacement: dimensions, winding and mounting conditions may change. Check the new core, bobbin and electrical design together.
ETD29, ETD39 or ETD44: how to choose a ferrite core for an SMPS →
Can every product marked CF139 use the same datasheet?
Verify which manufacturer owns the material designation and whether the supplied part actually uses that material. A similar label alone does not justify transferring another manufacturer's data.
ETD29, ETD39 or ETD44: how to choose a ferrite core for an SMPS →
Can an iron-powder toroid directly replace a ferrite toroid of the same size?
Do not assume a direct replacement. Check the material, inductance, operating current, losses and temperature conditions. Matching geometry does not replace these checks.
Ferrite vs iron-powder toroids: which core suits your inductor? →
Is a higher AL always better?
No. AL is one input to the target inductance and winding decision. It is not a standalone measure of quality or suitability without checking operating-current behaviour, losses and winding space.
Ferrite vs iron-powder toroids: which core suits your inductor? →
Is an external filter needed if the power supply already has one?
The requirement depends on the complete equipment, whose conditions may differ from the power supply's standalone test. Cable arrangement and load can create a need for additional filtering. Support the decision with measurements.
How to choose a single-phase EMI filter: current, leakage and installation →
Can two filters with the same current rating replace each other?
Current is only one criterion. Compare voltage, temperature, leakage current, attenuation conditions, terminal construction and mounting compatibility too.
How to choose a single-phase EMI filter: current, leakage and installation →
How many watts is an EE25 suitable for?
Size alone does not establish a fixed power rating. Topology, frequency, material, winding arrangement and permitted temperature rise must be assessed together.
How to choose an EE ferrite core: EE25 and EE42 replacement checks →
Do matching dimensions and AL prove equivalence?
No. Material losses, tolerances, gap arrangement and mechanical fit still need checking. Matching two parameters completes only part of the assessment.
How to choose an EE ferrite core: EE25 and EE42 replacement checks →
Can I enquire with only a sample?
For an initial review, share sample photographs, readable codes, dimensions and application information. The measurements or documents needed to resolve missing electrical information can then be identified.
What information is needed for a custom transformer quote? →
Should I choose the core before asking for a quote?
Share a core designation if your existing design specifies one. For a new design, provide the space and operating requirements rather than making an unconfirmed core choice mandatory.
What information is needed for a custom transformer quote? →
Is -52 always the better choice?
No. The identity of the documented material and the application's electrical, thermal and mechanical conditions determine suitability. A single loss comparison does not settle the whole design.
Does core colour prove its material?
Colour can help within a documented manufacturer's coding system. It cannot establish the material of a part with an unknown manufacturer.
What is the difference between a UU core and a UI core?
A UU set consists of two U halves; a UI set consists of one U half and a straight I piece. The UI combination has a shorter magnetic path, and for the same U part the AL value is higher.
How to choose a UU ferrite core: checklist for line filters and power transformers →
How many watts can a UU core handle?
Core size alone does not give a fixed power rating. Material, frequency, winding arrangement and permitted temperature rise must be assessed together. Power statements in manufacturer documents only apply to the stated conditions.
How to choose a UU ferrite core: checklist for line filters and power transformers →
What currents are UU-core line filter chokes used for?
That depends on the choke design. As an example, TDK lists its current-compensated U-core choke series for 0.4–2.6 A and 300 V AC.
How to choose a UU ferrite core: checklist for line filters and power transformers →
Quotes and contact
Why can't I see product prices on the site?
The site is Artek Elektronik's product catalog and does not show prices or stock. Prices are quoted according to the part definition and the required quantity. You can send an enquiry from the product page, by WhatsApp, by phone or by email.
What information should I send for a quote?
Send the part name or full dimensions, the existing manufacturer and part number if available, a photograph or drawing, the application (frequency, current, voltage) and the required quantity in a single message. If you do not know a value, mark it as unknown instead of guessing. The technical guides include detailed checklists for each product group.
What information is needed for a custom transformer quote? →
Which certificates does Artek Elektronik hold?
Artek Elektronik holds ISO 9001:2015 quality management, ISO 45001:2018 occupational health and safety management, and ISO 10002:2018 customer satisfaction management certificates. The documents state the scope as wholesale trade of electronic devices and parts; they do not certify each catalog product separately.
How can I contact Artek Elektronik?
You can reach Artek by phone (+90 212 252 11 68 or +90 532 718 33 64), WhatsApp, email (artek@ferritnuve.com) or the contact form. Address: Erişteci Sokak Abed Han No: 7/1, Karaköy, İstanbul, Türkiye.