Between the peak point and the valley point of UJT emitter characteristics, we have negative resistance region
Peak-Point Emitter Current (Ip): It is the emitter current at the peak point. It represents the minimum current that is required to trigger the device (UJT). It is inversely proportional to the inter-base voltage VBB.
Valley Point Voltage (VV): The valley point voltage is the emitter voltage at the valley point. The valley voltage increases with the increase in inter-base voltage VBB.
Valley Point Current (IV): The valley point current is the emitter current at the valley point. It increases with the increase in inter-base voltage VBB.