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一、概述晶体三极管的瞬态热阻Z_(th)是确定器件在脉冲工作状态下的集电极最大允许耗散功率P_(cmp)和确定其安全工作区的重要物理参数,对快速研究器件的热特性和检测器件的热性能参数亦有很大的实用价值。瞬态热阻Z_(th)的定义为:脉冲宽度为τ的单次功率脉冲加至被测管后,其等效结温Tj和给定的外部基准点温度的温差(小功率管为环境温度T_a,大功率管为壳温T_c)与脉冲功率P_(cp)之商。即:Z_(th)=Tj-T_a(或T_c)/P_(cp)………(1) 由(1)式可知,T_a(或T_c)和P_(cp)都是很容易测定的,而T_j则无法直接进行测试,只能通过器件的热敏参数V_(BE)(IEC所推荐使用的热敏参数,单位:mv)及其温
First, an overview of the transistor transient thermal resistance Z_ (th) is to determine the device in the pulse state of the maximum allowable collector power dissipation power P_ (cmp) and to determine the safe working area of the important physical parameters of the rapid study of the device Thermal characteristics and thermal performance parameters of the detection device also have great practical value. The transient thermal resistance Z_ (th) is defined as the temperature difference between the equivalent junction temperature Tj and the given external reference point temperature after a single power pulse of pulse width τ is applied to the pipe under test Temperature T_a, high-power tube shell temperature T_c) and pulse power P_ (cp) of the business. That is, Z_th = Tj_T_a or T_c / P_cp According to (1), T_a (or T_c) and P_ (cp) can be easily measured, and T_j can not be directly tested, only through the device thermal parameters V_ (BE) (IEC recommended thermal parameters, unit: mv) and its temperature