Lab Report Day Twenty - Phasors: Passive RL Circuit Response

Phasors: Passive RL Circuit Response

 

In this lab assignment, we measure the gain and phase responses of a passive RL circuit and compare these measurements with expectations based on analysis.

 

In the pre-lab, we predict the amplitude gain and phase difference with 3 different frequency: Wc, Wc/10, and 10Wc, where Wc is 2.2*10^5 Hz. We also find the cutoff frequency for the circuit. When W= Wc, we expect amplitude gain = 0.0321 and expect phase difference = -45degree. When frequency = Wc/10 expected amplitude gain = 0.0452 and expected phase difference = -5.711 degree. When frequency = 10Wc expected amplitude gain =4.52*10^-3 and expected phase difference = -84.3 degree. 

 

We use a 22 ohm resistor and a 100 uH inductor to build the circuit.

At f=35k Hz, Vin=989.4 mV, and I=31.25 mA. phase difference is -37.8 degree. Gain is 0.0316. 

At f=3.5k Hz, Vin=973.4 mV, and I=38.55 mA. phase difference is -6.3 degree. Gain is 0.0452. 

 

At f=350k Hz, Vin=994.8 mV, and I= 5.665 mA. phase difference is -78.12 degree. Gain is 5.695*10^-3. 

 

This is a summary table of our experiment including our percent difference, experimental value, and theoretical value for phase difference and gain.

 

Summary:

Today, we analyze the steady-state response of electrical circuits from sinusoidal inputs. We can find the amplitude gain by comparing the Vin and Vout. We also learn how to analyze AC circuits using different methods of analysis including nodal analysis, mesh analysis, superposition, Thevenin and norton analysis.