# Electronic – Help With Simulating Common Collector Amplifier In PSPICE

amplifierbjtsimulationspicetransistors

I have included as much information as possible, so it should just be a matter of pointing out something simple (hopefully).

I am trying to model a biasing circuit for a Common Collector BJT Amplifier. I am running a Transient Analysis on the circuit and am receiving the following simulation results (attached images), which I am having trouble interpreting. I have also listed my minimum specs for the circuit and my theoretically computed values. As far as I can tell, I am doing everything correctly, although I am not seeing how to choose the Collector Resistance since it does not appear in any of my equations. I am also not seeing the voltage gain nor the Q-point as computed by PSPICE in the simulation Output File.

MINIMUM SPECS:

Input Resistance >= \$5\$k\$\Omega\$
Output Resistance = \$50\Omega\$
Voltage Gain \$\geq 0.95\$ with \$5\$k\$\Omega\$ load
Output Voltage Swing of at least \$2\$Vpp across \$5\$k\$\Omega\$ load
\$V_{cc} \leq 20\$V

FORMULAS USED:

Input Resistance: \$R_1 || R_2 || (\beta+1)R_E\$
Output Resistance: \$R_E || r_{\pi}/(\beta+1)\$
Voltage Gain: $$\frac{R_E(\beta+1)}{r_{\pi} + R_E(\beta+1)}$$
\$G_m\$: \$I_c/0.026\$
\$r_{\pi}\$: \$\beta/G_m\$

COMPUTED VALUES:

\$R_1\$: \$36k\Omega\$
\$R_2\$: \$50k\Omega\$
\$R_e\$: \$10k\Omega\$
\$R_c\$: ?
\$r_{\pi}\$: \$5075\$
\$g_m\$: \$0.0197\$
\$I_c\$: \$5.122 \times 10^{-4}\$
Voltage Gain: \$0.995\$
Vb: \$5.772\$V
Input Resistance >= \$20.5\$k
Output Resistance = \$50\$
Output Voltage Swing of at least \$2\$Vpp across \$5\$k load
\$Vcc \leq 10\$V

• As you can see, I do not have a value for \$R_c\$, as I do not see how it affects any of my equations.

Circuit Image: Simulation Waveform Image: Simulation Waveform Cursor Values Image (Corresponds To Previous Waveform Image): Simulation Output File: • Where is the Q-POINT?