QUESTIONS & ANSWERS

摘要

I am not sure why the charging circuit on my weed charger fried (guessing battery went bad as it will no longer hold a charge), but the parts are not recognizable. The resulting fire appears to be localized to the transistor, and melted adjacent parts. I would like to fix the circuit board. My questions are: guess for the replacement of the TO92 transistor (or a better upgrade) and pass diode? 1.Why do other charging circuits typically heatsink the transistor? 2.What is the value of what looks to be a zener diode?