在模拟控制、计算和转换系统中,以适当的速度和高精度的转换模拟信号是一个重要课题。迄今为止,人们已经在这方面化费了大量的人力和物力,取得了很大的进展。模拟开关的发展大体上经历了由机电开关、双极型晶体管开关到结型和MOS型场效应晶体管开关的过程,产品则由分立元件逐渐转化到集成电路。如果不考虑速度,机电开关可以看成是近乎理想的开关(接通阻抗为零;断开阻抗为无限大)。双极型晶体管开 In analog control, calculation and conversion systems, the conversion of analog signals at an appropriate speed and accuracy is an important issue. So far, people have already spent a great deal of manpower and material resources in this regard, and great progress has been made. The development of analog switch generally goes through the process of switching from electromechanical switch to bipolar transistor to junction and MOS type field effect transistor, and the products are gradually transformed from discrete components to integrated circuits. If you do not consider the speed, the electromechanical switch can be regarded as a nearly ideal switch (on impedance is zero; off impedance is infinite). Bipolar transistor on