電子火牛既原埋及想DIY一個,請問有冇d簡單d既電子火牛電路圖??

去鴨記搵啦。坊間好多書都有講。但題目不是 電子火牛 而是 開關式電源變壓（或穩壓）器 Switching power Supply。基本上電腦火牛及大部份的手機充電器都是電子火牛。

Sorry typing in Chinese is too difficult, i have to switch back to english.

a switching power supply can be DC-DC / AC-AC / AC-DC / DC-AC and can also step up or step down. basically it use PWM (Pulse Width Modulation) to control the output voltage. compare to linear transformer, it have high efficiency (typical 75%-80% in PC power supply) generate less 'waste' heat and lighter weight (use less copper). However since the pulse width modulation part use high frequency, switching power supply is not recommended in analog or normal audio application.

if you want to go in depth refer to the following links

http://www.smpstech.com/
http://www.smps.us/