Introduction to ECSE

ECSE-1010 Fall 2017

Laboratory 05: LC Circuits

(Edit this document as needed)

Partner 1: ______

Partner 2: ______

Partner 3: ______(if needed)

Part A.1

Brief description of the experiment

Sketch of the Diode circuit, including labels where connections to the Discovery Board are required.

One sentence description of the measured voltage across R1 when considering a sinusoidal source voltage.

Voltage plots from the Discovery Board, including the sine wave input (W1), the voltage across R1 (W2), and the difference between the two plots (using the ADD feature). Label the voltages at several points on your plots.

Based on the plots, what impact does the diode have on the circuit?

Voltage plots from the Discovery Board, including both channels when the input is a square wave. Label the voltages at several points on your plots.


Sketch of the LC circuit.

1.  Calculated frequency at which the LC circuit oscillates

ωo (calculated resonant frequency) / [rad/s]
fo (calculated resonant frequency)
(remember, ω = 2πf) / Hz

Voltage plots of LC circuit from the Discovery Board, including both channels when the input is a square wave. Label the voltages at several points on your plots.

Time/div setting for the above plot.

Time/div

Period of oscillation

T / [s]

What triggering level did you use?

VTrigger / [V]
Rising or Falling

2.  Measured frequency of oscillation

ωo (resonant frequency) / [rad/s]
fo (resonant frequency)
(remember, ω = 2πf) / Hz

Voltage plots of LC circuit from the Discovery Board, including both channels when the input is a square wave with 1V and -2V output levels, with annotations.

Time/div setting
Measured period of oscillation, T

Describe how you set up the triggering.

Describe what happens when you change triggering.

Verification of experiment and plots : TA/Instructor’s initials ______

3.  Oscillation frequency

measured fo = 1/T
(resonant frequency) / Hz

Is your measured frequency a little smaller or a little larger than the calculated value?

Verification of experiment and plots: TA/Instructor’s initials ______

4.  Describe the waveform

Provide a description of the waveform and how it differs from theory.

What properties exist in an inductor that change the waveform from the expected plot?

Voltage plots of LC circuit from the Discovery Board, including both channels when the input is a square wave with 1V and -2V output levels, with annotations.

5.  Comparison of waveforms.

Describe the differences between the waveforms produced by the two different sources.

Experimentally, determine the oscillation frequency of the inductor by itself.

Measured period of oscillation, T
Measured fo = 1/T
(resonant frequency) / Hz

6.  Parasitic capacitance

Using the oscillation frequency equation, estimate the parasitic capacitance associated with the inductor.

Parasitic Capacitance / C

Measured resistance of the inductor.

RProbeWires / [Ω]
RInductor / [Ω]

Spec sheet value of inductor resistance

RSpecSheet / [Ω]

7.  Resistance effects on oscillation

How does your measured value compared to the reported value?

How does resistance affect the oscillation?

What aspect of the oscillating signal you measured for the LC circuit is caused by the resistance?

8.  (Extra Credit) Your answer to question 6 is likely to be incorrect if you have not taken the input capacitance of the scope into account. Correct your result using this additional information. Hint: Redraw the circuit including both the parasitic and input capacitors.

J. Braunstein Revised: 9/17/2017

Rensselaer Polytechnic Institute Troy, New York, USA