Calculate an R/I/V DC operating point

Use these steps in Altifigence Cloud 2.1.2.10. Sign in, select an organization with an active paid plan eligible for SPICE DC analysis, and open a Cloud project. The calculation runs locally in your browser.

Prepare the circuit

Create or open a .cir file in your workspace. Use a title on the first line, resistor and independent DC current- and voltage-source statements, one .op, and a final .end. Node 0 is ground. Give each node a resistor or voltage-source path to ground.

Keep the saved input within 64 KiB, 4,096 lines, 256 nodes including ground, and 1,024 elements. The total of non-ground node voltages and voltage-source currents can be at most 256 unknowns.

DC voltage-source example
V1 supply 0 DC 5
R1 supply load 1k
R2 load 0 1k
I1 load 0 DC 1m
.op
.end

Run the operating point

1. Save the .cir file.

2. In Flow Navigator, open Simulation → SPICE DC operating point (R/I/V).

3. Under Saved workspace .cir file, select or enter the saved file's workspace path.

4. Select Run DC operating point.

Read and save the results

Read Node voltages in volts and Branch currents in amperes, including the current through each voltage source. A positive voltage source sets its first terminal above its second terminal by the specified voltage. Positive branch current follows the first terminal to the second terminal written in each statement.

The result shows the input SHA-256, IR SHA-256, KCL residual, voltage constraint residual, and fixed tolerances. Select Download result JSON to save the result, or Download table CSV to save the tables. To view a saved JSON result later, select Open saved result JSON.

Correct a circuit diagnostic

If the panel shows a diagnostic with a source line, use its Open … at line …, column … link to open that statement. Correct the circuit, save it, and select Run DC operating point again.

See Digital Design Studio for the project workspace.