This Privacy Policy (hereinafter "Policy") applies to the "Flyback Transformer Designer" application (hereinafter "Application," "we," or "us"). This Policy explains how we handle information related to your device. Please read it before using.
"Flyback Transformer Designer" is a local computation and design assistance tool for flyback transformers, supporting multiple secondary outputs and operating modes such as DCM / BCM / QR / CCM. The interface offers Simplified Chinese and English display; language preference is primarily determined by your device's system or browser language settings and does not change the data handling principles described in this Policy. The application's built-in core and material data are stored on-device via the installation package, not obtained from uploading your device data. We follow the principle of privacy-first with computation and data primarily completed locally on your device: your design content and "My Database" are by default stored only on your device; unless otherwise stated below, we do not collect personally identifiable information for advertising or third-party sharing.
2.1 Basic Principles
This application does not upload your design schemes, transformer specification parameters, or "My Database" contents to the developer's servers; we cannot remotely read such data from your device.
2.2 Information Processed on Your Device
Data you input or generate includes but is not limited to:
PDF reports and JSON design files you generate on your device are created locally; if you share them via system sharing, AirDrop, email, or other applications, they are handled by your chosen recipient according to their terms.
The above information is used solely to present calculation results and export files on your device and is not uploaded to the developer's servers.
2.3 Analytics and Diagnostics (Anonymous)
We may learn of device model, system version, and aggregated usage information through standard mechanisms provided by Apple (such as App Analytics and anonymous crash statistics), without including your design details. You can disable "Share iPhone & iCloud Analytics" and similar options in your device's "Settings" → "Privacy & Security" → "Analytics & Improvements" to limit such reporting.
Design data is primarily stored in the application's on-device sandbox. Uninstalling the application or clearing data will delete local content according to system behavior. If you enable iCloud backup, some data may enter device backup via Apple's iCloud service, the handling of which is governed by Apple's Privacy Policy, and we cannot access your iCloud contents.
A 3-day full-feature trial start time is stored in the on-device Keychain (and, if you enable iCloud Keychain, may sync with your Apple ID) so the trial is not reset by simply deleting and reinstalling the app. This timestamp is used only to determine whether the trial is still active; it is not uploaded to the developer. After the trial, unlocking steps 2–3, My Database editing, and export requires a one-time App Store purchase (non-consumable). Existing annual subscriptions remain valid until they expire and can be restored with the same Apple ID. The application reads valid StoreKit / App Store purchase or subscription transaction status when needed, and may cache unlock status locally for interface display and basic state continuity while offline.
We do not sell design data. In accordance with application distribution, payment, and system service requirements, Apple (App Store, App Store Connect, one-time purchases / remaining subscriptions, and receipts) and network communication recipients you actively choose (such as hosting providers of privacy policy or technical support pages opened in your browser) handle minimally necessary information related to their respective connections according to their own terms.
If you open instructional, privacy policy, or technical support pages provided with the application in your browser, static content is loaded over HTTPS and does not contain embedded tracking scripts for personal tracking. External links such as GitHub Issues are accessed at your own discretion via your browser.
This application is not designed for children under 13 years of age; we do not knowingly collect personal information from children.
You can manage design schemes and "My Database" within the application; uninstalling the application deletes local design content according to system behavior. The 3-day trial timestamp may remain in Keychain as described above. One-time purchases, receipts, and any remaining annual subscriptions are handled by Apple (App Store); related account settings are managed by you in the system and App Store.
We may update this Policy and update the "Last updated" date on this page; material changes will be communicated through app store release notes or appropriate in-application notices. Continued use constitutes acceptance of the updated Policy.
Email: Deepthinker2026@outlook.com
You may also contact us through the support channel on the application's App Store page.
This application is distributed via the Apple platform and supports iPhone, iPad, and can be installed on Apple silicon Macs through the App Store with an iOS/iPad-compatible version (specific app store presentation may vary). Regardless of which device you use, the data handling principles remain the same: design and calculation take place on your current device, and this product does not transmit your design file contents to the developer.
The application requires no location, contacts, microphone, or other unnecessary permissions to use core functionality; core iteration and loss calculation can be completed offline; opening App Store purchases, verifying receipts, or browsing web help requires network connectivity.
On macOS, the system will request Gatekeeper verification of application integrity on first run (Apple's official security mechanism), which requires network connectivity; thereafter, the application can run offline. Design projects are stored in the application sandbox and are not shared with other applications.
The 3-day trial is timed on-device as described above. The one-time purchase (and any remaining annual subscription) is completed via Apple (App Store), as shown in-application and by Apple. We do not use purchases for third-party advertising profiling.