# Name Section  Introduction to ac simulation

 ECE 213 Electrical Circuits Lab II LAB #9 Fall 2013 Name ___________________ Section ______________ Introduction to AC Simulation OBJECTIVE: Each student will be able to use: (a) Simulation program to determine voltage and current amplitudes and phase angles in an AC circuit, and (b) the AC sweep capability of the simulation program to compute and plot the frequency response of a circuit. COMPONENTS AND EQUIPMENT: Oscilloscope Function Generator Digital Multimeter Personal Computer Simulation Program (PSPICE, LTSPICE (free), Cadence, TINA) PROCEDURE: Single-Frequency Analysis: The circuit has L = 210 mH, R = 1 kΩ, C = 480 nF, and the sinusoidal source shown in the figure is described by the equation: Figure - Circuit Diagram vg = 3sin(2πf t) V where f = 1 kHz The voltage 3V is the amplitude of voltage (Vpeak = 3V). Solve the circuit by finding voltages on each node, voltage across each component, and the current across the circuit. Show all the calculation. Then Find out real and reactive power in each component. Use amplitude voltage for calculation. Use simulation to find the magnitude and phase of each node, VL, VR, VC (across component), and the current in the series circuit; Check the simulation results against an analytical solution. Report percent error. Construct the circuit and measure the voltage on each node including phase, voltage and phase across L, R, and C, and current. Capture the waveform from Oscilloscope. Tabulate the result in the report. If possible, take a picture of the constructed circuit. A schematic representation of this circuit is shown below. N1 N3 N2 Figure - Circuit Schematic Swept Frequency Analysis Part A: AC Sweep Place Node 1, 2, 3… on all the connector between each component. Place voltage marker on the node 2 and 3. Select AC Sweep as the type of analysis. Since we only need a single frequency, set the Start and End “sweep” frequencies to the same value and Number of Total Points to 1. Screen shot the node voltage. Note that we must specify the source file frequency in Hertz. Then set the Number of Total Point to 100, frequency from 10Hz to 2kHz. Sweep and plot the Voltage node, voltage across R, L, and C. Capture the waveform with results shown in the plot. Label the node voltage at 1kHz. Does the value agree to calculation? Find out the resonant frequency of the circuit at VR (Voltage acorss R) by plotting a range of frequency. The resonant frequency is frequency where voltage is at peak. Output the simulation values and open them in a spreadsheet. Values can be saved in either Rectangular or Polar form. Put a portion of this output into your lab book. Parametric Analysis This part is to vary the R1 in several difference values. Change the schematic by replacing the value of R with a "global parameter" named r_value contained in curly brackets: {r_value}; the curly brackets are used to indicate a global parameter. “r_value” can be x, y, z. It’s just a variable. Find the part call “PARAM”. The default value of such a parameter is specified using the part named PARAM. Double click the PARAM part to specify a default value of r_value; do not use the curly brackets here. Set the default value of r_value to 1 kΩ, the original value of R. During a swept frequency analysis, a global parameter can also be swept using a "parametric sweep". Examine the Parametric option under Options and notice the type of information required to specify the Sweep Variable Type and Sweep Type. List the possible Sweep Variable Types and the possible Sweep Types. Use what you have just learned about AC Sweep analysis and about parametric sweeps to examine the effect of the resistor value on the magnitude response. Use the following list of values (Use List Value in configuration): 500 Ω, 1 kΩ, 2k, and 5 kΩ. Label the results at 1kHz. Paste the waveform in your report. Example of a schematic is shown below. Plot Vout (Node 3: between R and C). Capture the waveform. Figure – Example: AC Sweep with Parametric Analysis Figure - Parametric Analysis QUESTIONS: Explain what AC Sweep is and the usage of it. Explain what Transient Analysis is. Explain the Parametric Analysis What is the voltage between the inductor and resistor at 0.6kHz from simulation? Think of an application where you will need to use RLC circuit.