Experiment: The OCTCA and High-Frequency Response Due to Intrinsic Capacitances

  

Figure 4.15: Circuit for Measuring High Frequency Intrinsic Capacitors

Use the circuit in Fig. 4.15 to perform this experiment.

1.

Measure the voltage gain of this circuit as a function of frequency. Take approximately two measurements per/decade, starting from 10Hz and going to 10MHz.

2.

Analyze the circuit using the Miller approach, and the OCTCA. From your analysis and your experimental results, provide values for the intrinsic capacitor $C_{\mu}$.Assume that due to the Miller effect, is $C_{\mu}$ is dominant, and $C_{\pi}$ can be neglected.

3.

Extra Credit Now that you have determined $C_{\mu}$, try to find $C_{\pi}$. To do this, set R_C=0, and measure $\frac{\Delta v_B}{v_{in}}$ and keep in mind that the capacitance that you calculate will be that of $C_{\pi}$ and $C_{\mu}$ in parallel.