# OLB Viewer

Free online OLB viewer. Open and preview OrCAD library files (.olb, .dra) directly in your browser — no upload, no software.

> Canonical page: https://elysiatools.com/en/viewers/olb

- **Category:** Diagrams

- **Supported formats:** .olb, .dra

## Overview

This OLB viewer renders OrCAD library files directly in your browser. OLB (.olb) is Cadence OrCAD's symbol library format, storing electronic component symbols for schematic design. DRA (.dra) is the drawing format. Pick a sample library or choose your own .olb / .dra file to preview its contents instantly, with no upload.

## When to use

- You received an .olb file from an OrCAD user and want to inspect it.
- You need a quick, private preview of component symbols.
- You want to check OrCAD library contents without the software.

## How it works

- Select a built-in sample library or choose your own .olb / .dra file.
- The viewer parses the OrCAD binary format in your browser — nothing is uploaded.
- Inspect the library parts, symbols and pin definitions.

## Use cases

- Previewing OrCAD component libraries.
- Checking schematic symbols without OrCAD.
- Inspecting PCB design library exports.

## Samples

- **Sample OLB**: A OLB sample for in-browser preview

## Frequently asked questions

### What is an OLB file?

OLB (.olb) is Cadence OrCAD's library file format for storing electronic component symbols used in schematic capture. It contains part definitions, graphical symbols, pin assignments and package information in a proprietary binary format based on Microsoft's Compound File Binary (CFB) structure.

### What is a DRA file?

DRA (.dra) is Cadence OrCAD/Allegro's drawing file format, storing the physical layout artwork for PCB components including padstacks, package outlines and silkscreen markings.

### Are my OLB files uploaded?

No. Files you open from your device stay on your device and are parsed locally. Only the public sample file is requested from the server.

## Related content

- [Draw.io Viewer](https://elysiatools.com/en/viewers/drawio): Open and preview Draw.io diagrams (.drawio, .dio) directly in your browser — no upload, no software.
- [Excalidraw Viewer](https://elysiatools.com/en/viewers/excalidraw): Open and preview Excalidraw diagrams (.excalidraw) directly in your browser — no upload, no software.
- [Mermaid Viewer](https://elysiatools.com/en/viewers/mermaid): Open and preview Mermaid diagrams (.mermaid, .mmd) directly in your browser — no upload, no software.
- [PlantUML Viewer](https://elysiatools.com/en/viewers/plantuml): Open and preview PlantUML diagrams (.plantuml, .puml) directly in your browser — no upload, no software.
- [XMind Viewer](https://elysiatools.com/en/viewers/xmind): Open and preview XMind mind maps (.xmind) directly in your browser — no upload, no software.
- [GeoJSON Viewer](https://elysiatools.com/en/viewers/geojson): Open and preview GeoJSON geographic data (.geojson) directly in your browser — no upload, no software.