Abstract:

The basic principles and concepts of impedance matching are presented.Impedance matching is commonly used between the amplifiers at all levels,amplifier and load,signal and transmission circuit,and even between microwave circuit and system design.The fundamental reason is that mis-matching of voltage and current in the low-frequency circuit and electromagnetic wave in the high frequency circuit may lead to serious reflection and damage instruments and equipment.Impedance matching is the solution,which is discussed in this paper.

Key words: impedance matching;noise;circuit