this circuit works as a SCR and formed using mos and opamp. Input is SINE wave at opamp and Gate terminal is square wave at other terminal of opamp and output is mos output. So its a 3 terminal device with gate and anode as opamo terminal and cathode as mos terminal . It will only pass the wave when gate voltage is more than anode voltage . It simulates SCR and this condition is same as gate triggering.But the fault is that gate does not looses its control after triggering i.e. we can commitatethus device using gate also.
