Engineering notes
Technical guides
Core selection, choke sizing, filter design and what to send with a specification — written by the people who wind the parts, for the people who have to choose them.
- 2 min read
Bay note 01 — The print that gets a quote in one exchange
A winding-bay checklist of the eight numbers, plus a worked peak-current strip so the first sample is the right sample.
Read the guide - Ferrite Transformers2 min read
Bay note 02 — Core geometry before core size
EE, ETD, PQ and RM are not interchangeable blanks. Geometry decides leakage, window and heat — with an area-product worked example for a 65 W flyback.
Read the guide - Ferrite Transformers2 min read
Bay note 03 — Turns, AL and the gap (flyback math that sticks)
From Faraday to AL·N² with a full numerical strip: primary turns, secondary turns, gap intuition and why AL is the number on the core box.
Read the guide - Common Mode Chokes1 min read
Bay note 04 — Common-mode choke from the noise floor up
Size Lc from the dB you must kill, not from a catalogue guess — with a worked 150 kHz LISN example and the ferrite vs nanocrystalline fork.
Read the guide - Power Inductors1 min read
Bay note 05 — Power inductor: Isat against DCR
A buck/boost inductor strip that faces saturation current, ripple ratio and copper loss as one decision — not three separate catalogue filters.
Read the guide - Toroidal Power Inductors1 min read
Bay note 06 — Toroidal when the field must stay home
Why a closed magnetic path changes EMI, mounting and winding cost — with a comparison strip against bobbin ferrite for the same inductance.
Read the guide - 1 min read
Bay note 07 — Copper loss, core loss and the temperature you actually get
A thermal strip that adds winding loss and core loss, then translates watts into rise — so sample approval is not a surprise on the hot plate.
Read the guide - Ferrite Transformers1 min read
Bay note 08 — Isolation and creepage on purpose
Functional vs reinforced is a winding architecture, not a sticker. How tape, margins and bobbin choice change when the barrier is mains-referenced.
Read the guide - Line Filters1 min read
Bay note 09 — Line filter stages without guesswork
X caps, Y caps and CM/DM chokes as a sequence — how to specify a line filter so the bay builds a stage, not a lucky LC.
Read the guide - 1 min read
Bay note 10 — From sample to identical production
What is allowed to change between prototype and volume — and the three things that must be frozen on the print so the hundredth part matches the first.
Read the guide - Drum Core Chokes1 min read
Bay note 11 — Drum core when an open path is correct
Open magnetic path, cheap mounting, real EMI cost — when a drum-core choke is the honest answer for a power rail.
Read the guide - Air Core Inductors1 min read
Bay note 12 — Air core: linearity without a ferrite
No core loss, no saturation, more turns — when air-core inductors earn their board space in RF and precision paths.
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