一、引言众所周知,晶体管有放大信号的功能,但当输入交流信号频率升高时,晶体管放大能力要下降,这是所有晶体管的共性.然而实际测量表明:不同晶体管放大能力显著下降的频率各不相同,例如有的晶体管(低频管)的放大能力在几十千赫就开始下降了,但高频和微波晶体管一直可以工作到几百兆赫甚至更高,而且同一种型号的晶体管的放大能力也相差甚多.这些都说明了合理和正确测量晶体管的高频特性就显得极为 I. INTRODUCTION As we all know, the transistor has the function of amplifying the signal, but when the frequency of the input AC signal increases, the amplification capability of the transistor needs to be reduced, which is the commonality of all the transistors. However, the actual measurements show that the frequencies of different transistors have significantly decreased Similarly, the amplification capability of some transistors (low-frequency tubes), for example, starts to decline at tens of kilohertz, but high-frequency and microwave transistors can work up to several hundreds of megahertz or even more, and the amplification capability of transistors of the same type A lot of difference between these shows that the reasonable and correct measurement of the high frequency characteristics of the transistor becomes extremely