# Flyback Transformer Designer — Iterate·Custom Lib·Offline

> Iterate·Custom Lib·Offline (iPhone/iPad app by 建忠 徐.)

- Source: https://appshunter.io/ios/app/flyback-transformer-designer/id6771727431 (this page in markdown: same URL + `.md`)
- Developer: [建忠 徐](https://appshunter.io/developer/1871049057)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 8 MB
- Languages: English, Chinese
- Released: 2026-05-26
- Data updated: 2026-06-25
- User reviews in markdown: https://appshunter.io/ios/app/flyback-transformer-designer/id6771727431/reviews.md

## What is Flyback Transformer Designer?

Flyback Transformer Designer turns your flyback power supply spec into a complete transformer design — core, gap, turns, wire gauge, and loss breakdown — all computed locally on your device, no internet required.

Built for power-electronics engineers who need more than a spreadsheet. Covers all four operating modes: DCM, BCM, QR, and CCM. Supports multi-output secondaries with independent winding design, not a simplified single-output approximation.

Three steps to a finished design:
1. Enter your spec — Vin range, output voltages, power, frequency, and design constraints.
2. Review the top 5 core candidates — gap, Lm, winding layout, wire selection, copper/core losses, and temperature-rise estimates; switch the ranking between balanced, high-reliability, or lowest-loss.
3. Export a professional summary report (PDF or JSON).

Why you'll like it:
- Full core × turns × wire-gauge iteration with built-in AP pre-screening — no more flipping through datasheets by hand.
- Optional Bmax design ceiling — leave it blank and the engine guards against saturation automatically using the material's Bsat×70% margin, so an overly conservative guess won't rule out viable designs; set your own ceiling anytime for an extra constraint.
- Built-in ferrite core library (EE, RM, PQ, ETD, etc.) plus My Database for your own materials, cores, and bobbins.
- Parameter sweep — explore f_sw, load, and Vin sensitivity curves before you wind a single turn.
- 100% local computation; your data never leaves your device.
- Native support for iPhone, iPad, and Mac (Apple silicon); switch between Chinese and English.

14-day free trial — full functionality included. After the trial, an annual subscription (via App Store in-app purchase) is required to continue using steps 2–3, My Database, and export.

Privacy Policy: https://tobebetter2026.github.io/Public-documents-Flyback-Transformer-Designer/privacy-policy.html
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ (Apple Standard EULA)

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Annual subscription | $29.99 | per year |



## Version history (last 2 releases)

### 2.0 — 2026-06-07

1. Switchable ranking for core candidates — re-sort the top 5 by balanced pick, high reliability, or lowest loss, depending on what matters most for your design.

2. More trustworthy core selection — operating points are now self-consistently recomputed from the actual integer  turns ratio, with a new hot-spot gap-permeability recheck that filters out candidates that could drift out of spec at high temperature, so results track real-world winding and thermal behavior more closely.
  
3. Bmax design ceiling is now optional — leave it blank and the engine guards against saturation automatically using  the material's Bsat×70% margin, so an overly conservative guess won't rule out viable designs; set your own ceiling anytime when you need an extra constraint, for a more flexible and realistic filtering process.

### 1.0 — 2026-05-27

No release notes.

## More apps by 建忠 徐

- [Inductor Design Pro](https://appshunter.io/ios/app/inductor-design-pro/id6758878884)

All apps by 建忠 徐: https://appshunter.io/developer/1871049057

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-25.*