power transistor features
1. On-state characteristics: modulation effect occurs in the base area and collector area under large injection, and the on-state voltage drop is very low
2. Switching characteristics: current concentration phenomenon during turn-off: due to the self-bias effect in the base area, the edge of the emitter is reversely biased during the transistor turn-off process, the edge is turned off but the center is still turned on, so current concentration occurs phenomenon
3. The secondary breakdown characteristics are the same as all relays. It is worth noting that after the first avalanche breakdown, the ability added to the BJT exceeds the critical value before the secondary breakdown occurs, which means that the secondary breakdown requires energy.