Because of the stability of LED current, these designs provide an expanded input-ac-voltage range, which may be useful for a multistandard ac-powered gadget;
由于LED电流的稳定性，这些设计使输入交流电压的范围扩大，其有利于多标准交流供电设计；
2
An ACpowered source usually has a significant level (often several volts) of line frequency common mode voltage.
交流供电的源通常具有很高电平的电源频率共模电压(常常有几伏)。
3
The Pinnacle is battery powered when in operating mode ensuring that potentially harmful 110 V AC power is kept away from your patient.