LTspice Viewer

LTspice from Analog Devices is the free circuit simulator most electronics students, hobbyists and power supply engineers use. Its schematics are .asc files, and they travel everywhere: a lecturer shares the lab circuit, a forum answer attaches a fixed design, a colleague mails an op-amp filter, and Analog Devices publishes a ready-made demo circuit for many of its chips. The catch is that LTspice runs only on Windows and macOS. On a phone, a Chromebook, a Linux laptop or a locked office PC there is nothing to open the file with, and the .asc itself is just a list of coordinates. This page draws it in a few seconds anywhere.

The drawing follows the file exactly. Wires, junction dots, net labels, ground symbols, input and output ports, comments and SPICE directives sit where LTspice put them, and the common parts are drawn from their own outlines: resistors, capacitors, polarised capacitors, inductors, diodes, Zeners, Schottkys, LEDs, voltage and current sources, behavioural sources, controlled sources, switches, NPN and PNP transistors, MOSFETs, JFETs and op-amps, in every rotation and mirror. Reference names and values are printed next to each part, just as you see them in LTspice.

Tap any wire and the whole net lights up, with a line telling you its name and every pin on it, such as Q1.C, RC.B and Cout.B. That makes it quick to check how a circuit hangs together without tracing lines by eye. Below the drawing you get a parts list grouped by type and value (for example R1, R3, R4: Resistor, 10k), the simulation commands such as .tran, .ac or .step, the notes written on the sheet, and the full SPICE netlist with unnamed nets numbered N001, N002 like LTspice.

Parts from LTspice's own chip library, such as a switching regulator IC, keep their drawing in a separate .asy symbol file that is not inside the .asc. They show as a dashed box with the part name, and the page tells you which symbol files are missing. Add those .asy files with the schematic, or drop a ZIP of the project folder, and they are drawn properly and included in the netlist.

Your schematic never leaves your device. The .asc and .asy files are read by code running in this tab, and the images, PDF, netlist and CSV are made on your computer as well. There is no upload, no account and no AI model, so unreleased designs and coursework stay private. Closing the tab clears everything.

This is a viewer, not a simulator. It does not run the circuit or show waveforms, and you cannot edit the schematic. Text that LTspice shows rotated (such as labels on sideways parts) is drawn level so it stays readable, and fonts can differ slightly from LTspice. Hierarchical sheets open one at a time when you add their .asc files together.