基于共集放大电路的系统设计与性能研究

In order to meet the requirements of high input impedance and low output impedance matching in sensor signal acquisition scenarios, a signal amplification system based on basic co-set amplification circuit (emitter follower) is designed in this paper. The static operating point stability is realized through the voltage-dividing bias network, and the impedance matching problem between the sensor and the post-stage circuit is solved by combining the high input impedance, low output impedance and voltage following characteristics of the common collection circuit. Theoretical analysis and Multisim simulation show that the input impedance of the circuit is 120kΩ, the output impedance is reduced to 80Ω, the voltage gain is 0.98±0.02, and the distortion THD is <0.5% in the frequency band of 10Hz-100kHz, which effectively improves the stability and load capacity of weak signal acquisition, and is suitable for signal buffering and amplification of high-precision sensors.