Thyristor (SCR)

Single-phase thyristor / silicon-controlled rectifier (SCR). A gate-triggered, latching switch: it turns ON when the gate signal exceeds its threshold AND the device is forward-biased (anode above cathode), then conducts like a diode with a forward-voltage drop and low on-resistance. The gate has NO turn-off control — once latched the device stays ON and only turns OFF by natural (line) commutation when its forward current falls to zero. Use as the controllable valve in phase-controlled rectifiers and line-commutated converters (e.g. HVDC).

Category: Single-Phase / Switching

Ports

Name	Direction	Value type	Notes
a	electrical	double
c	electrical	double
g	input	double

Parameters

Config

Name	Label	Type	Default	Units	Description
v_forward	Vf	double	0.7	—	Forward conduction threshold / on-state voltage drop in volts.
resistance_on	R_on	double	0.05	Ohms (Ω, kΩ, MΩ)	Conducting (latched-on) resistance. Pick a unit from the dropdown.
resistance_off	R_off	double	1000000	Ohms (Ω, kΩ, MΩ)	Blocking (forward- or reverse-blocking) resistance. Pick a unit from the dropdown.
gate_threshold	V_th(g)	double	0.5	—	Gate input threshold; a gate signal above this fires the device while it is forward-biased.
measure_current	Measure current	enum (Off / On)	0	—	Emit branch current as a simulator observable.

Current Monitoring

Name	Label	Type	Default	Units	Description
current_name	Current name	string	I	—	Signal name for the measured branch current (A, anode → cathode). Change the default `I` when you have multiple measured components — duplicate ids collide.

Observables

Signal	Type	Default name	Enable	Description
branchCurrent	signal	from current_name	measure_current	Branch current through the thyristor (A, anode → cathode).