Assume first that SCR1 is on and SCR2 is off so that CI is fully charged, with its LMP2 end positive. The
state of the circuit can be changed by pressing S2. As SCR2 turns on, it turns SCR1 off capacitively via its anode. Capacitor CI then recharges in the opposite manner (i.e., the left end is now positive). The state of the circuit can be changed again by pressing SI, thus driving SCR1 on by way of its gate, and driving SCR2 off capacitively via its anode.