In the identical working tempt the difference between tempt on the surface and the working tempt is even greater and that reduces the working life of the heatingfilament.
同样工作温度，丝表面温度与工作温度相差更大，从而降低电热丝的寿命。
2
The heater is composed of a housing, a heatingfilament arranged in the housing, and a switch, a transformer and a power plug sequentially connected with the heatingfilament.
加热器由外壳，设于外壳内的加热丝，以及与加热丝依次连接的开关、变压器、电源插头构成。
3
Semiconductor devices have no filament or heaters and therefore require no heating power or warm-up time.