SPICE Shell

SPICE Shell #

The SPICE Shell shows the full SPICE netlist that Breadpad generates from your breadboard, and lets you run it directly. Breadpad’s engine is ngspice, a modern, open-source implementation of Berkeley SPICE. This is the place to add simulation directives that aren’t exposed in the standard oscilloscope modes, or to run an imported netlist.

Opening it #

Open the oscilloscope and choose SPICE Shell. You’ll see the netlist for your current circuit, which you can review, edit, and run.

Netlist basics #

Each line describes a component or a directive:

  • Components start with a type letter — R resistor, C capacitor, L inductor, D diode, Q transistor, V voltage source.
  • Nodes are names or numbers; node 0 is ground.
  • Comments start with * or ;.
R1 1 2 1k   ; 1k resistor between nodes 1 and 2

Useful directives #

Because you’re editing the raw netlist, you can use ngspice analysis directives directly — including sweeps that don’t have a dedicated oscilloscope mode:

  • .op — operating point
  • .tran <step> <stop> [<start> [<max-step>]] — transient
  • .ac <dec|oct|lin> <points> <start> <stop> — AC small-signal
  • .dc <source> <start> <stop> <step> — DC sweep
  • .temp <value> — set the simulation temperature
  • .model / .subckt … .ends — define models and subcircuits
  • .save <vars> — choose which outputs to keep

Importing & exporting netlists #

Breadpad opens PSPICE and LTspice netlists (.spice and .cir) and runs them directly. You can also review the generated netlist here before sharing a design.

Tips #

  • Start from the auto-generated netlist and make small, documented changes.
  • Use comments so you remember what each custom directive does.
  • For convergence trouble, see Troubleshooting.

Learn more #