需求
“Draw a 12 V car battery overcharge alert with a fuse, reverse-polarity diode, zener threshold, transistor, buzzer, red overcharge LED and green power LED.”
接著試試Change the overcharge threshold to 14 V.Add a relay output for an external alarm.
這張圖裡有什麼
看懂背後的決策。
01
Use a series reverse-polarity diode and fuse for input protection
02
Set threshold with a 13V zener and base resistor
03
Drive buzzer and red LED with NPN transistor; green LED shows normal power
Reuse for low-side switched alarms where a battery or DC voltage should trigger audible and visual warning above a set threshold.