Mumbai University > Electronics Engineering > Sem 4 > Discrete Electronic Circuits

Marks: 5M

Year: May 2015

Figure 1: Circuit diagram of CS amplifier.

Above figure shown the circuit diagram for CS amplifier where $C_g$, $C_d$ acts as coupling capacitor and $C_s$ acts as bypass capacitor.

The small signal ac equivalent circuit is shown below:

Figure 2: Small signal equivalent circuit of CS amplifier.

The above circuit is drawn for mid-band frequency range where all the capacitor acts as short circuit. Hence $C_s$ makes $R_s$ short circuit.

Voltage Gain:

$A_v = \frac{Vo}{Vin} = - g_m (R_D || r_d)$

Input Resistance:

Rin = $R_1 || R_2$

Output Resistance:

Ro = $R_D || r_d$