drag from palette onto grid · click part then canvas to place · in wire mode drag pin → pin
grid0,0toolselectV select · W wire (drag pin→pin) · R rotate · Del remove · ⌘Z undo · F fit
Schematic editor
Toolbar:File for new/open/save/export/clear; Simulate for DC analysis; ? for this help; gear for display options.
Editing: drag symbols from the palette or arm one and click the canvas; V select, W wire (pin→pin or two grid clicks); rotate and mirror on the strip below the filter.
How it worksModified nodal analysis
Every net in the schematic is one unknown voltage. The DC solver writes Kirchhoff's Current Law at each non-ground net (current in = current out), expresses every branch current in terms of node voltages and Ohm's law (I = (V₁ − V₂) / R), and gets a linear system G v = i.
Voltage sources add a constraint row: V+ − V− = E, plus an extra unknown (the current through the source). Solve via Gaussian elimination; every node voltage falls out at once. That's how SPICE has done DC analysis since 1973.
This editor handles resistors, voltage sources, current sources, ammeters, and voltmeters. Diodes / transistors / op-amps draw but don't simulate (they need iterative Newton, out of scope for this lesson).