三点式振荡器是指LC回路的三个端点与晶体管的三个电极分别连接而成的电路，如图4-1（a）所示。图中三个电抗元件X1、X2、X3构成了决定振荡频率的并联谐振回路，同时也构成了正反馈所需的反馈网络。从相位条件看，要构成振荡器，必须满足： (1)极相连的两个电抗X1、X2性质相同。 (2)X1与X2、X3的电抗性质相反。-three-point refers to LC oscillator circuit with three transistors endpoint of three electr

RFID卡片与读头电路频率谐振电路调试工具。-RFID card reader circuit with frequency resonant circuit debugging tools.

以改变输入回路的高端谐振频率，使之始终低于本机振荡频率465kHz。所以微调电容C主要用于调整波段高端的接收灵敏度。-To change the resonant frequency of the input circuit of the high-end, so that is always lower than the local oscillation frequency 465kHz. It is mainly used to adjust the trimmer capacitor C