Hi,
I am trying to amplify the ac input signal but any input value results in 0V output, Can anyone what's wrong with my circuit? I don't want to use a voltage divider bias configuration.
Variations in bias due to temperature and beta may be reduced by moving the VBB end of the base-bias resistor to
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Why is voltage divider bias a more stable bias than a collector feedback bias?
I have to make some assumptions about what you are really asking. There are 2 major ways to bias a bipolar junction transistor (BJT). The first is with a resistor in the emitter and a voltage divider to the base. Works great. The emitter resistor raises the input impedance and controls the gain. The second way is to connect a resistor between the collector and the base with the normal collector pull-up resistor to Vcc. Also works great. This method lowers the input impedance and controls the gain.
There is one disadvantage of the shown bias scheme if compared with the Re method (emitter resistor):
The input resistance is reduced (Miller effect) whereas RE will increase the input resistance.
For this reason, I think that the Re-feedback is the preferred method for stabilizing the Q-point,
Yes, although the input impedance is likely dominated by the low Rbe of a grounded-emitter amp (in the neighborhood of a few kΩ, depending upon the emitter current).
Interesting, the distortion of a grounded emitter amp due to the non-linear input current versus input voltage, can be reduced if the base drive is a high-impedance (constant-current) source, such as from the collector of a common-emitter input stage.