By applying a forward-biased voltage to this triac L4004L5 thyristor manufactured from Littelfuse the bistable switch will continue to stay on. This device has a surge current rating of 40 A. Its repetitive peak forward blocking voltage is 400 V, while its repetitive peak reverse voltage is 400 V. This SCR thyristor has an operating temperature range of -40 °C to 110 °C.