情境
When a laptop loses power and its charger is reconnected, this circuit automatically presses the power button for a short duration, turning the laptop on without manual intervention.
這張圖裡有什麼
看懂背後的決策。
01
Use an RC differentiator (C1/R2) to generate a low trigger pulse on VCC power-up.
02
Select Rt and Ct to set a pulse width long enough for the laptop's power button hold time (typically 100–500 ms).
03
Drive a relay via a transistor to isolate the laptop's power button pins.
Useful for laptops used as servers, kiosks, or unattended systems that must power on automatically after AC power is restored.