如果采用的网络比文氏电桥的Q值高,那么一个场效应管可提供一个性能优良的频率可变的音频信号源。在使用一个场效应管作稳幅元件时如图1所示的电路,可复盖频率200～2000Hz,而且失真度小于0.02％,追加的频率范围可增到20～200Hz及2～20KHz,在这种情况下,C_2相应地改为10μF或0.1μF。为了使幅度在20～200Hz范围内都相等,可用一个几兆欧的电阻并联在确定颊率的电容器上,或者用一个几百欧的电阻和它串联,从而分别减小在频率范围高 If the network used is higher than the Q value of the Wien bridge, then a FET can provide a high performance, variable frequency audio source. When using a FET as a stable component, the circuit as shown in FIG. 1 can cover the frequency of 200-2000Hz and the distortion is less than 0.02%. The additional frequency range can be increased to 20-200Hz and 2-20KHz. In this case, C_2 is changed to 10μF or 0.1μF accordingly. In order to make the amplitude in the range of 20 ~ 200Hz equal to a few megaohms of resistance can be connected in parallel with a certain cheek rate of the capacitor, or with a few hundred ohms resistor and it in series, respectively, in the frequency range to reduce the high