PC221 Analog Electronics I

LC Circuits

Objectives

1. To examine inductor charging and discharging
2. To examine frequency response of an LC circuit
3. To continue measurement of phase in AC circuits
4. To continue the use of SPICE circuit simulation including AC analysis.
5. To compare results of analysis, measurement, and simulation.

Equipment

• digital multimeter, bench power, oscilloscope
• various resistors and capacitors and inductors
  

Procedure

Here we'll look at a slightly different filter circuit. The difference with this circuit is that it will have a resonance. In other words V_L/V will have either a maximum or a minimum at a specific frequency.

• L = 1.2 mH
• R_L = 1.0 kΩ
• C = 10 μF

Circuit Measurement: Digital Multimeter

1. Measure the component values with a digital multimeter, and fill them in Table 1.
   
   Here's a link on measuring inductance using the TENMA meter.
   
   

   Table 1: Component Values and Voltages
   Quantity	Measured Value	Units
   L
   RL
   C
   V (amplitude)
   V (offset)

   
   
   
2. Perform all of the same kinds of analysis you did for the RC filter circuit so that you can compare the results, and present your results the same way. Remember to use the measured values from Table 1 for your calculations and simulation.
   
   Be sure to measure both V and V_L at each frequency in order to find the resonant frequency. Adjust the input signal, if needed, to keep the same amplitude at each frequency.
   Try to find the resonant frequency as precisely as possible.
   
   For this reason, use at least 10 points per decade in your simulation.
   
   
   
   Show your results to the lab instructor.