perminvar alloys

例句：

1. 1. The transformeris used to convert alternating currentinto direct current.
   变压器用于将交流电转换为直流电。
2. 2. The variator is adevice that adjusts the voltage level ofan electrical circuit.
   变压器是一种调节电路电压水平的设备。
3. 3. The regulator controls the temperaturein a heating system by varying the amountof gas flowing through it.
   调节器通过改变流过加热系统的气体量来控制温度。