# PHY10004 Question

ECEN 214-516

**Pre-Lab 8**

Sinusoidal Steady State Response of a 2nd Order Circuit

1. Design a Sallen-Key circuit as shown in Figure 8.1. Choose component values so that the circuit produces an underdamped response with a Q-factor of Q = 3/2 and a resonant radian frequency of rad/sec (Hz). Refer to the previous lab to refresh your memory on these quantities if needed. Be sure to choose component values that are available to you in your lab kit. Also, try to avoid using very small resistors (less than a few hundred Ohms) as that may cause bad behavior from your op amp. **Provide a plot of the magnitude and phase response of your circuit similar to the ones provided in Figure 8.3. In your plot, the frequency should be in a logarithmic scale and should range from 10Hz to 10kHz. **

Q |
R1 |
R2 |
C1 |
C2 |

1.515 |
200kΩ |
360kΩ |
1μF |
0.1μF |

**2. **Modify your circuit by exchanging the positions of the resistors and the capacitors as shown in Figure 8.4. Keep the same component values as you used in part A, just move their positions as shown in the Figure. **Develop an equation that provides the relationship between the phasor input and phasor output of the circuit. From this relationship develop a formula for the magnitude and phase response of the circuit. Show your derivations.** **Provide a plot of the magnitude and phase response of your modified circuit.**