Skip to content
Charles Gantt edited this page Oct 11, 2026 · 2 revisions

FAQ

Is it free?

Yes. It is free for personal, educational, and commercial use. It uses the Apache License 2.0. See License for the conditions (keeping the license, the copyright and attribution notices, and the NOTICE contents).

Does it work on my phone?

Yes. The layout adapts to narrow screens. The tab grid becomes four columns on a phone, and the results stack neatly.

Does it need an internet connection?

The tool runs entirely in your browser. After the page has loaded, it does not send your input anywhere, and it does not need a server to decode anything. The picture and the data are all part of the page.

Why did it give me two answers?

Some markings are genuinely ambiguous. 47R can be an EIA-96 code (3.01 Ω) or 47 Ω written in R notation. A 107C can be a ceramic capacitor with a tolerance letter or a 100 µF 16 V tantalum. The tool shows both readings (or lets you choose the type) rather than guessing silently.

It says "tolerance not marked." Why?

Many markings do not encode tolerance. A 3-digit SMD resistor code, for example, only gives the value. Where the style usually implies a tolerance, the tool shows the typical one and says it is an estimate. Otherwise, check the datasheet.

Why does a part number show a different pinout than my datasheet?

Pinouts can differ between manufacturers, even for the same part number. The cards say which maker's order is shown. Your datasheet is the authority for your part.

A part I need is not in the Semiconductors list. Can I add it?

You can request it by opening an issue, or add it yourself. Entries live in js/parts-data.js in the repository. See the Embedding and Customizing page. Please include a source for any numbers.

Can I put it on my own website?

Yes, for commercial and non-commercial sites. You must include the Apache 2.0 license and keep the copyright and NOTICE attribution notices, and we ask that you keep the footer attribution visible. See License and Embedding and Customizing.

Can I change it and add features?

Yes. Modifying and adding are allowed. The license, the copyright and attribution notices, and the NOTICE contents must remain, you should mark files you changed, and you can add your own credit alongside them.

Why do I see the attribution footer even in a single-tab view?

The footer credit is how people trace the tool back to its source and find the User Guide, so it stays visible in every view, including the one-tab embed. We ask that you keep it if you host the tool.

How do I report a bug or a wrong value?

Open an issue. For a wrong value, please include the datasheet or standard that shows the right one.

Is this a safety tool?

No. It helps you identify parts and learn marking schemes. For mains circuits, fuses, and surge protection, always confirm against the manufacturer datasheet and follow your local electrical codes.

Clone this wiki locally