A circuit element, named bistable resistor (or biristor), is proposed. The biristor has two stable resistance states. A high resistance state and low leakage current are maintained until an applied voltage reaches a latch-up voltage to trigger an avalanche effect. A low resistance state and high current are attained at voltage above the latch up. The low resistance state is latched until the applied voltage decreases down to the latch-down voltage. Bistable resistance states are achieved between the latch-down and the latch-up voltage. In addition, an optical stimulus appears to reduce the latch voltages.