Struct PentodeModel 

pub struct PentodeModel {
    pub mu: f64,
    pub kp: f64,
    pub kvb: f64,
    pub ex: f64,
    pub kvb2: f64,
    pub vg2_default: f64,
    pub kg1: f64,
    pub kg2: f64,
    pub rp: f64,
}

Pentode model parameters using a screen-referenced Koren equation.

Pentodes have five electrodes: cathode, control grid (g1), screen grid (g2), suppressor grid (g3, usually tied to cathode), and plate. The screen grid acts as the “effective plate” for controlling current — the plate merely collects it, giving pentodes their characteristic flat plate curves and high output impedance.

The screen-referenced Koren equation:

E1 = Kp * (1/mu + Vg1k/Vg2k)
Ip_base = (Vg2k/Kp * ln(1 + exp(E1)))^Ex
Ip = (Ip_base / KG1) * atan(Vpk / KVB)

The atan term models the pentode’s plate saturation characteristic — plate current is nearly independent of Vpk in the normal operating region. KG1 scales the absolute plate current magnitude.

Fields

mu: f64

Amplification factor (mu), screen-referenced. EF86 ≈ 38, EL84 ≈ 19.

kp: f64

Plate resistance factor. Affects output impedance.

kvb: f64

Knee voltage constant for the screen-referenced Koren equation.

ex: f64

Exponent (typically 1.3-1.5). Affects transfer curve shape.

kvb2: f64

Knee voltage for pentode plate saturation (V). Controls how quickly plate current saturates with Vpk. Smaller = sharper knee. EF86 ≈ 12, EL84 ≈ 20.

vg2_default: f64

Default screen grid voltage (V) for typical operating point.

kg1: f64

Plate current scaling factor (KG1). Scales the absolute plate current magnitude in the Koren equation.

kg2: f64

Screen current scaling factor (KG2). Reserved for future screen current modeling (requires separate WDF current source).

rp: f64

Plate resistance at typical operating point (Ω). Used as virtual resistance in WDF tree construction. Power pentodes: 15k–50kΩ. Signal pentodes (EF86): ~2.5MΩ.

Trait Implementations

impl Clone for PentodeModel

fn clone(&self) -> PentodeModel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PentodeModel

impl Debug for PentodeModel

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

Formats the value using the given formatter.