How to remove degradation in voltage gain when replacing the original \$R_L\$ with a small value resistor

amplifierbjttransistors

For the following common-emitter amplifier, the original \$R_L = 4.7\space kΩ\$. When I replace it with a small value resistor (\$100\spaceΩ\$), the voltage gain will drop. Is there any way to drive the new low-impedance load without causing the degradation in the voltage gain?


Circuit Diagram

Circuit Diagram


SetUp Details

\$
\space \space \space \space \space \space \space \space R_G=600\space Ω \\
\space \space \space \space \space \space \space \space R_1=82\space kΩ \\
\space \space \space \space \space \space \space \space R_2=15\space kΩ \\
\space \space \space \space \space \space \space \space R_C=4.7\space kΩ\\
\space \space \space \space \space \space \space \space R_E=910\space Ω \\
\space \space \space \space \space \space \space \space R_L=4.7\space kΩ
\$


Thank you for your help.

Best Answer

Your output resistance is mostly controlled by Rc, which is 4.7k, so you are going to get a lot of loss driving such a small load resistance. To maintain gain and drive the low resistance you need a common collector buffer, as Photon said.