Simplified model of m
triodes for alternating current, each built from two antiparallel thyristors.
thyristor1
has to be fired during the positive halfwave of the voltage.
thyristor2
has to be fired during the negative halfwave of the voltage.
Note: A real triac is fired in positive direction (thyristor1
) by a positive gate current and in negative direction (thyristor2
) by a negative gate current.
The triac goes in blocking condition when the current falls to zero.
This behaviour is simulated by the two firing gates fire1
and fire2
:
fire1=false
and fire2=false
: gate current = 0, stay in blocking conditionfire1=true
and fire2=false
: gate current > 0, fire thyristor1
fire1=false
and fire2=true
: gate current < 0, fire thyristor2
fire1=true
and fire2=true
: forbidden