Auster 隨手亂彈

自鎖式按鈕開關(帶燈開關)做為後級開關用,但這開關上有五個pin
其中兩個pin是給開關上LED燈用的,接+12V電壓,另三pin才是控制開關,GND, NC (Normal Close),NO (Normal Open),
想一按下去Power On時同時LED燈亮,但此接法只能接+12V電源的開關,若接110V會導致燒毀LED燈

單純點燈就不必再買變壓器，參考以下的電路：

12V/1W Zener Diode 可選用 1N4742(1N4742A) 或 13V/1W 的 1N4743(1N4743A)，
因用電是 110Vac，那麼 220nF/250V 數值要加倍，可以在 330nF~560nF 之間依實驗修正決定最妥當。

12 Volts Transformerless Power Supply

This 12 Volts transformerless power supply take advantage of the fact that a Zener diode is also a normal diode that conducts current in the forward direction. During one half wave, the current ?ows via D1 through the load and back via D4, while during the other half wave it ?ows via D3 and D2. Bear in mind that with this circuit (and with the bridge rectifier version), the zero voltage reference of the DC voltage is not directly connected to the neutral line of the 230-V circuit.