(ii) When MT2 is negative w.r.t. MT1 and appropriate gate current is allowed in the gate circuit, SCR2 is turned ON and SCR1 is OFF. In terms of transistor equivalent circuit, Q3 an Q4 are forward biased while Q1 and Q2 are reverse biased. Therefore, transistors Q3 and Q4 will conduct as shown in Fig. 21.7 (i). As explained above, the current in load RL will quickly attain a large value. The circuit will behave as if a switch is closed between MT2 and MT1.