CIRCUIT File

What are CIRCUIT files and how to open them

Are you having problems opening a CIRCUIT file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CIRCUIT files.

What is a CIRCUIT file?

A .CIRCUIT file is a KTechlab Circuit Design file.

KTechlab circuit design files store edited schematics of electronic circuits, including digital, analog, and mixed‐signal elements, created for design and simulation in the KTechlab application. They capture both the visual layout (component placement, orientation, wiring) and the behavioral parameters (values for resistors, capacitors, logic gates, etc.), so that circuits built with components can be simulated, probed for voltages or currents, and modified in either form.

These files are produced and read by the KTechlab program, an open‐source IDE that runs on Linux under KDE. Users draw circuits by placing components from a library, connect them (either manually or via automated routing), set numeric or string parameters for each part, and save the whole design all in one file. Upon opening, the file allows continuing construction or simulation of the circuit, including viewing component values, altering layout, and inspecting connectivity.

Internally the design files are stored in XML. The root includes a doctype declaration identifying the document as type circuit. Items representing components ("item" elements) declare component types (resistor, capacitor, logic gate, external connection, ground etc.), position (x, y, z), orientation (angle, flip), and parameter data (e.g. resistance, capacitance, numeric or string values). Connections are represented using "connector" elements with attributes like start‐node, end‐node, manual route data, and "node" elements record node coordinates and identifiers.

As a technical signature the file begins with something like "<!DOCTYPE KTechlab>" followed by "<document type="circuit">". Internally it uses tags and attributes such as item, connector, node, data, with identifiers like id, type, angle, flip, start-node-parent, end-node-child, manual-route.

How to open CIRCUIT files

Important: Different programs may use files with the CIRCUIT file extension for different purposes, so unless you are sure which format your CIRCUIT file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single CIRCUIT opener which you will find listed below.

Last updated: August 31, 2026

Various apps that use files with this extension

These apps are known to open certain types of CIRCUIT files. Remember, different programs may use CIRCUIT files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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