# 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 VL/V will have either a maximum or a minimum at a specific frequency.

You'll be using the circuit shown, with the components as follows: V is a 1V AC sine wave (of varying frequency) source with a DC offset of 5V, like this:

The other values are;
• L = 1.2 mH
• RL = 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.

Quantity Table 1: Component Values and Voltages 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 VL 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.

Before you leave the lab, have the lab instructor sign your lab notebook immediately after your last entry.

## Resources

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Since this page uses cascading style sheets for its layout, it will look best with a browser which supports the specifications as fully as possible.

If you are looking for an office package, with a word processor, spreadsheet, etc., you might try LibreOffice which is
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Go to the main page for the Department of Physics and Computer Science.

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