## 3.19 `S`: Voltage Controlled Switch

### 3.19.1 Syntax

`S` xxxxxxx n+ n– nc+ nc– mname {ic}
`.VSWitch` label n+ n– nc+ nc– mname {ic}

### 3.19.2 Purpose

Voltage controlled switch.

### 3.19.3 Comments

N+ and n– are the positive and negative element nodes, respectively. Nc+ and nc– are the controlling nodes. Mname is the model name. A switch is a resistor between n+ and n–. The value of the resistor is determined by the state of the switch.
The resistance between n+ and n– will be RON when the controlling voltage (between nc+ and nc–) is above VT + VH. The resistance will be ROFF when the controlling voltage is below VT - VH. When the controlling voltage is between VT - VH and VT + VH, the resistance will retain its prior value.
You may specify `ON` or `OFF` to indicate the initial state of the switch when the controlling voltage is in the hysteresis region.
`RON` and `ROFF` must have finite positive values.

### 3.19.4 Model Parameters

`VT` = x
  Threshold voltage. (Default = 0.)
`VH` = x
  Hysteresis voltage. (Default = 0.)
`RON` = x
  On resistance. (Default = 1.)
`ROFF` = x
  Off resistance. (Default = 1e12)