Question

Difference between unbypassed and bypassed emitter bias circuit

Answer 1

Emitter Bypass Capacitor. When an emitter resistance is added in a CE (Common Emitter) amplifier, its voltage gain is reduced, but the input impedance increases. Whenever bypass capacitor is connected in parallel with an emitter resistance, the voltage gain of CE amplifier increases.

unbypassed current is that... that is not passes through conductor

Answer 2

The difference between an unbypassed and bypassed emitter bias circuit is that in an unbypassed emitter bias circuit, the capacitor is connected as shown in the figure while in bypassed emitter bias circuit, the capacitor is connected parallel to the emitter resistance.

Explanation:

• The emitter bias circuit is the common emitter configuration amplifier circuit which can be of two types, i.e., unbypassed and bypassed.
• The differences between the unbypassed and bypassed emitter bias circuit are given below.

    Unbypassed emitter bias circuit:

• The unbypassed emitter circuit is shown in the first figure.

• In the unbypassed emitter bias circuit, the resistance $\[{R_E}\]$ called the emitter resistance, provides the feedback and output stability to the circuit.
• But it also decreases the voltage gain and due to this, AC signal and noise also increase in the output.

Bypassed emitter bias circuit:

• To improve the performance of an unbypassed circuit, a capacitor is connected parallel to the emitter resistance.
• Now, this circuit is called bypassed emitter circuit.
• The capacitor $\[{C_E}\]$ connected parallel to $\[{R_E}\]$ is called the emitter bypass capacitor which bypasses the AC signal and decreases the noise in the output.

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