Struct JfetVariableResistor 

pub struct JfetVariableResistor {
    pub model: JfetModel,
    /* private fields */
}

JFET operating as a voltage-controlled variable resistor.

In phaser circuits, JFETs operate in the triode region with small Vds, where they act as voltage-controlled resistors. The drain-source resistance Rds varies with the gate-source voltage Vgs:

Rds = Rds_on / (1 - Vgs/Vp)²

where:

• Rds_on = 1 / (2 × β × |Vp|) — resistance at Vgs = 0
• Vp = VTO — pinch-off voltage (negative for N-channel)

This replaces the full Newton-Raphson JFET solver for LFO-modulated JFETs that serve as variable resistors (e.g., Phase 90 all-pass stages).

Fields

model: JfetModel

Implementations

impl JfetVariableResistor

pub fn new(model: JfetModel) -> JfetVariableResistor

pub fn set_vgs(&mut self, vgs: f64)

Set the gate-source voltage and update Rds.

pub fn vgs(&self) -> f64

Current gate-source voltage.

pub fn rds(&self) -> f64

Current drain-source resistance.

pub fn rds_on(&self) -> f64

Resistance at Vgs = 0.

pub fn process_root(&self, a: f64, rp: f64) -> f64

Process as a WDF root: simple resistor reflection.

Returns the reflected wave for a resistive termination with resistance Rds at the root port with tree port resistance Rp:

b = a × (Rds - Rp) / (Rds + Rp)

Trait Implementations

impl Clone for JfetVariableResistor

fn clone(&self) -> JfetVariableResistor

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ControlledResistance for JfetVariableResistor

fn set_control(&mut self, value: f64)

Set the control value (0.0 = minimum effect, 1.0 = maximum effect).

fn effective_control(&self) -> f64

Get the current effective control level (after any internal filtering).

impl Copy for JfetVariableResistor

impl Debug for JfetVariableResistor

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl WdfLeaf for JfetVariableResistor

fn port_resistance(&self) -> f64

Port resistance seen looking into this element (Ω).

fn reflected(&self) -> f64

Produce the reflected wave given the current state.

fn set_incident(&mut self, _a: f64)

Accept the incident wave after scatter_down phase.

fn set_sample_rate(&mut self, _sample_rate: f64)

Update sample rate (for reactive elements C, L).

fn reset(&mut self)

Reset internal state to zero.