The .NODESET statement provides initial guesses for node voltages to help the DC operating point solver converge. Unlike .IC, these are suggestions rather than forced values.
.NODESET V(<node1>)=<value> [V(<node2>)=<value> ...]
| Parameter | Description |
|---|---|
V(<node>) |
Node name wrapped in V() |
value |
Suggested initial voltage |
.NODESET V(OUT)=5 V(MID)=2.5
| Feature | .IC | .NODESET |
|---|---|---|
| Effect | Forces initial voltage (with UIC) |
Suggests starting guess for solver |
Requires UIC |
Yes | No |
| Use case | Transient initial conditions | DC convergence help |
| Overridden by solver | No | Yes — solver refines from guess |
Use .NODESET when the DC operating point solver has difficulty converging:
Bistable circuit
R1 VCC OUT1 10k
R2 VCC OUT2 10k
Q1 OUT1 OUT2 0 NPN_MODEL
Q2 OUT2 OUT1 0 NPN_MODEL
V1 VCC 0 5
.model NPN_MODEL NPN(Is=1e-14 Bf=100)
.NODESET V(OUT1)=5 V(OUT2)=0.2
.OP
.SAVE V(OUT1) V(OUT2)
.END