User guide
How to open a schematic PDF in Schematic Viewer, highlight nets, step through labels with the same name, find parts and export the lists as CSV — screen by screen.
Schematic Viewer is a free web tool that reads the lines and text in a schematic PDF, infers which wires are connected (nets), and overlays the result on the original drawing. It runs in your browser with no installation or account, and your file is never uploaded. This guide walks through the screens in the order you will meet them.
1. Open a schematic PDF
In the tool, choose Choose PDF or drop a PDF anywhere on the page to start the analysis. Dropping another PDF while a drawing is open replaces it; the Open another PDF button at the top does the same.
No schematic at hand? Start with the example schematic — the ESP32-PoE board published by Olimex. The step-by-step example walks through it.
Analysis takes a few seconds depending on page count and complexity. Drawing the original PDF may take a moment longer; a "Rendering drawing" indicator is shown meanwhile.
2. The screen
- Top bar: site logo (back to the home page), file name, page numbers for multi-page PDFs, Open another PDF, and the language switch.
- List: search box, the Nets tab (named nets split into power and signals) and the Parts tab (references and values). It sits on the left on laptops, desktops and phones held sideways, and as a sheet under the drawing on phones held upright.
- Drawing: the original PDF, with only the analysis (highlights, search hits) drawn on top. Use the buttons at the bottom right to zoom or fit the drawing.
3. Highlight a net
Click a wire or a net label and every wire identified as part of the same net is highlighted in cyan while the rest of the drawing fades. The highlighted part itself is left out of the fading so the original lines stay crisp. Picking a name in the Nets tab does the same and zooms to fit the whole net.
Under the list, the selection panel shows the number of wires and junctions, the labels and pin names on the net, and the pages it appears on. Fold it away with the chevron, or press Esc to clear the selection.
Step through labels with the same name
A net listed as +3.3V ×11 has eleven labels with that name. Click the selected net in the list again, or use the Labels ◀ ▶ buttons in the selection panel, to jump to 1/11, 2/11 and so on; the label you land on gets a blinking outline. Labels on other pages are followed across pages.
4. Search
Type any text written on the drawing — a net name, pin name, reference or value — and every match is outlined in amber. After two or more characters and a short pause the view moves to the best match without pressing Enter. Use the ▲ ▼ buttons in the bar above the drawing to go to the previous or next match; Enter brings you back to the current one.
Search matches parts of words, but exact matches always come first. Searching R1 shows R1 before R10–R19, and the bar adds the number of exact matches ("exact 1"). The lists are sorted the same way.
5. Find parts
The Parts tab lists the reference designators found on the drawing (R1, C3, U2 …) with the values written next to them. Click one to jump to it with its reference outlined, or click a reference directly in the drawing. See Finding parts in a schematic PDF for tips.
6. Export the lists as CSV
The Nets CSV or Parts CSV button above the list saves the whole list of the open tab as a CSV file: name, type (power/signal), label count and pages for nets; reference, value and pages for parts. A UTF-8 byte order mark is added so Excel opens it directly, and names such as +5V that spreadsheets would treat as formulas are written so they show as text. The file is created in your browser and downloaded directly; it is not sent anywhere.
7. Moving around and shortcuts
| Action | Mouse and keyboard | Touch |
|---|---|---|
| Zoom | Mouse wheel, + / -, trackpad pinch | Pinch with two fingers |
| Pan | Drag, arrow keys | Drag with one finger |
| Zoom into a spot | Double-click (Shift+double-click zooms out) | Double-tap |
| Fit drawing | 0 or the bottom-right button | Bottom-right button |
| Clear selection / search | Esc | × in the selection panel |
8. On a phone
Held upright, the list folds into a one-line sheet under the drawing so the drawing gets most of the screen. Tap the sheet to open the search box and lists; picking an item folds it again. With a net selected, the sheet shows its name and the label buttons. Turn the phone sideways and the list moves to the left like on a computer; fold it with the ‹ button.
9. Can I trust the result?
Connections are inferred from what is drawn in the PDF and may differ from the netlist in the CAD source. Before a design change or a repair, check against the original drawing and CAD data. Cases that work less well, and what to do about them, are listed in Supported files and troubleshooting.