Glossary
circsim shows a plain-language label first and the technical term second. Hover a dotted-underlined word in the app, or look it up here. The definitions below are the same ones the app shows, and each links to the page that explains it in full.
Chip power pin
Also called: VDD
The positive supply pin of a digital chip. circsim reads its voltage to decide what counts as a logic high.
Read more: Read the warnings & fidelity banner
Connection
Also called: net
Every pad and trace that is wired together. All the points on one net sit at the same voltage.
Gentler solve
Also called: gmin stepping
A fallback the solver uses when a straight solve will not settle: it adds tiny helper connections to ground and removes them step by step. The answer can be less trustworthy, so circsim flags it.
Read more: Read the warnings & fidelity banner
Ground (0 V reference)
Also called: ground net, SPICE node 0
The net every other voltage is measured against. The simulator needs exactly one, so Power On and Run stay disabled until you pick it.
Read more: Set ground & supply
High level
Also called: V High
The voltage the logic output drives when it is set to HI. Set it to match the logic power rail of the chip you are driving.
Read more: Bench instruments reference
Ignore this part
Also called: Stub open
Leave this part's pins unconnected, as if it were not fitted. Right for a part you want removed from the simulation.
Read more: Models & resolution
Live run
Also called: transient simulation
The Run button: the circuit is simulated moment by moment so you can watch voltages change on the scope.
Read more: Probe nets & read the scope
No model found
Also called: unresolved
circsim has no model for this part, so it contributes nothing to the simulation. Fix it in the Model Doctor.
Read more: Fix an unresolved part
Pin matching
Also called: pin map: pad to model terminal
Which pad on the board connects to which terminal of the part's simulation model. Wrong matching gives wrong results, for example a diode that conducts backwards.
Read more: Fix an unresolved part
Placeholder part
Also called: stub
A stand-in used when a part has no real model: its pins are left unconnected, tied together, or driven by hand from a panel.
Read more: Models & resolution
Power supply
Also called: PSU
A bench power supply: an adjustable DC voltage you clip onto a net. Its return goes through your ground.
Read more: Bench instruments reference
Ramped solve
Also called: source stepping
A second fallback: the supplies are brought up from zero in small steps instead of all at once. Like the gentler solve, the result is flagged because it can be less trustworthy.
Read more: Read the warnings & fidelity banner
Replace with a wire
Also called: Stub short
Tie all of this part's pins together, as a jumper, a fitted zero-ohm resistor, or a closed switch would.
Read more: Models & resolution
Simulation settings from the schematic
Also called: Sim.* fields
Optional properties on schematic symbols (Sim.Device, Sim.Pins and so on) that tell the simulator what a part is. Attaching the schematic gives circsim exact pin names and models.
Read more: Attach a schematic
Source resistance
Also called: Series R
The supply's internal resistance. Near zero is an ideal supply; raise it to model a weak source whose voltage sags under load.
Read more: Bench instruments reference
Steady-state voltages
Also called: DC operating point
The voltage on every net and the current through every part once everything has settled and nothing is changing. It is the same as measuring a powered board with a multimeter.
Read more: Energize & read the operating point
The simulator's full log
Also called: raw ngspice log
The unedited text from ngspice, the simulation engine inside circsim. Useful to copy into a bug report; you do not need to read it.
Read more: Read the warnings & fidelity banner
Total resistance
Also called: Total R
The potentiometer value from end to end, before the wiper splits it.
Read more: Bench instruments reference
Unconnected net
Also called: floating node
A net with no DC path to ground, such as an input wired to nothing. The simulator cannot decide its voltage, which is a common reason a solve fails.
Read more: Read the warnings & fidelity banner
Variable resistor
Also called: rheostat
The potentiometer used as a two-terminal resistor whose value you turn between zero and its total.
Read more: Bench instruments reference
Voltage divider
Also called: divider
The potentiometer used with three terminals: the ends sit across a voltage and the wiper gives a voltage somewhere between them.
Read more: Bench instruments reference