1, common emitter:
The negative electrode of the power supply serves as a common ground. The positive terminal of the power supply is connected to the C terminal through the load resistance. E pole is grounded. Indirect bias resistance between B and C poles, and the signal is capacitatively coupled to B. After amplification, the coupling capacitor is produced from the C pole.
The negative electrode of the power supply serves as a common ground. The positive terminal of the power supply is connected to C, and the E terminal is grounded through the load resistance. The B pole is connected to the positive terminal of the power supply through the bias resistance. The signal is capacitatively coupled to B. After amplification, the coupling capacitance is generated from the E pole.
The load resistance size is selected by the signal size such as several hundred to several K. The size of the bias resistance to the load resistance voltage drop is about 1\/2 of the power supply.