基于BJT和JFET的AGC电路的设计和实现  

Design and Realization of AGC Based on BJT and JFET

作　　者：易双[1] 荣军[1] 刘祥松[1] 张积伦 张志华[1] 

机构地区：[1]湖南理工学院信息与通信工程学院

出　　处：《电子技术（上海）》2014年第4期67-68,48,共3页Electronic Technology

摘　　要：设计了自动增益控制电路,能够使放大电路的增益自动随信号强度的变化而调整。该电路通过采用改变BJT的直流工作状态来改变BJT的电流放大系数β,实现电阻分压以及改变JFET的栅源电压来控制放大器电阻的大小。设计的自动增益控制电路阐述了BJT分压、JFET变阻以及AGC电路的工作原理,实现了可控增益范围大约为40dB,对现实教学和应用都有很好的借鉴意义。The paper designs an automatic gain control （AGC） circuit, enabling the gain of amplifier circuit automatically adjusted with the change of signal strength. The circuit changes the current amplification coefficient β of BJT by means of changing the DC working state of BJT, so as to realize the partial pressure and control the resistance of the amplifier by changing the S gate voltage of JFET. The designed AGC circuit describes BJT partial pressure, JFET variable resistance, and the working principle of AGC circuit. The obtained controllable gain range is about 40dB, and the system has very good reference significance for the practical teaching and application.

关 键 词：自动控制 自动增益控制 BJT分压 JFET变阻 

分 类 号：TN386.6[电子电信—物理电子学]