avalanche current การใช้

SPADs, like avalanche photodiodes ( APDs ), exploit the photon-triggered avalanche current of a reversely biased p n junction to detect an incident radiation.
This voltage happens at the point where the processes of base current generation and the bipolar transistor turning on are in balance : the collector-emitter current of the bipolar transistor decreases the collector voltage, which results in a lower electric field, which results in a smaller impact ionization or avalanche current and thus smaller base current, which weakens the bipolar action.