## 3.15 `L`: Inductor

### 3.15.1 Syntax

#### Device

`L`*xxxxxxx n+ n– value*

`L`*xxxxxxx n+ n– expression*

`L`*xxxxxxx n+ n– value*
{`IC=`*initial-current*}

`.inductor` *label n+ n– expression*
#### Model (optional)

`.model` *mname* `TABLE` {*args*}
### 3.15.2 Purpose

Inductor, or general flux storage element.
### 3.15.3 Comments

*N+* and *n–* are the positive and negative element nodes,
respectively. *Value* is the inductance in Henries.

The (optional) initial condition is the initial (time = 0) value of
the inductor current (in Amperes). Note that the initial conditions
(if any) apply only if the `UIC` option is specified on the `transient` command.

You may specify the *value* in any of these forms:
- A simple value. This is the inductance in Henrys.

- An expression, as described in the behavioral modeling chapter. The
expression can specify the flux as a function of current, or the
inductance as a function of time.

- A
*model*, as described in the behavioral modeling chapter. The
`table` model describes a table of flux linkages vs. current.

### 3.15.4 Probes

The following probes (Transient, DC, and OP analysis) are available in
addition to those available for all basic elements. See the `print` command for documentation.
`DT`-
Time step. The internal time step used for this device for numerical
integration. It is not necessarily the same as the global time step.

`TIME`-
Time. The time of the most recent calculation of this device. It is
not necessarily the same as the global time.

`TIMEOLD`-
The time of the previous calculation of this device. It is not
necessarily the same as the global time.

`TIMEFUTURE`-
The latest recommended time for the next sample, as determined by this
device. The actual time will probably be sooner than this.

`DTREQUIRED`-
The required approximate maximum time step, usually based on
truncation error estimation.

`FLUX`-
The flux linkages stored in this inductor, in Weber-turns.

`INDUCTANCE`-
The effective inductance of this device. For a fixed inductor, it
be its value. For a nonlinear inductor, it is the effective
inductance at this time, or ∂ ϕ / ∂
*v*.

`DLDT`-
The time derivative of inductance. For a linear inductor it will be
zero.

`DL`-
The change in inductance compared to the previous sample. Its
primary use is in debugging models and numerical problems. For a
linear inductor it will be zero.

`DFDT`-
The time derivative of flux. Hopefully this is the same as voltage,
but it is calculated a different way and can be used as an accuracy
check.

`DFLUX`-
The change in flux linkages compared to the previous sample. Its
primary use is in debugging models and numerical problems.