Voltage divider with AC bypasses capacitor:

Figure: Voltage divider with capacitor

The standard voltage divider circuit that is discussed above faces a drawback - AC feedback caused through resistor R_E reduces the gain. This can be prevented by placing a capacitor (C_E) in parallel with R_E, as displayed in circuit diagram.

This capacitor is generally selected to have a low enough reactance at the signal frequencies of interest such that R_E is necessarily shorted at AC, so grounding the emitter. Hence feedback is only present at DC to stabilize the operating point, in which case any AC benefits of feedback are lost.

Certainly, this idea can be employed to shunt only a portion of R_E, hence retaining some AC feedback.