Chem 8153 January 2009 1 Laboratory 1 Solving Circuits: Microcap The objectives of this laboratory session are: (1) Learn how to use Microcap to solve basic circuits and represent their behavior. (2) Reinforce the concepts of frequency and time dependence of AC measurements. (3) Design a circuit, predict its behavior and test it experimentally. Introduction Microcap is a software package useful to define and solve circuits. The time initially invested in learning the software quickly pays off as it makes it possible to draw complex circuits, obtain current and voltage values at various nodes, determine the power dissipation at each component, and generate various representations in the frequency and time domain. Other features can be found at, http://www.spectrum-soft.com/demo.shtm. This laboratory consists of two parts: (A) Practice the use of Microcap by solving assigned circuits, and (B) Design your own circuit, solve it using Microcap, and test the solutions by making the actual circuit in a Proto-Board. Prelab Prior to this lab session, gain access to Micro-Cap 9 and look at the General Demonstration in the Help Menu. Components and Equipment Needed 1. Microcap software 2. DMM 3. Proto-Board 4. Oscilloscope and probes 5. Resistors and capacitors 6. Jumper wires A. Practice the use of Microcap Before beginning the circuits below, make sure that you have watched the Microcap tutorial. When drawing the circuit some helpful hints are: press the left mouse button and click on the right mouse button to rotate circuit components; use the spacebar to toggle between the pointer and the active function. When solving circuits some helpful hints are: use the right mouse to find out what parameters are available. When copying your graphs and circuit for export to word documents, etc., “copy to clipboard”. Then you may paste in the desired application.Chem 8153 January 2009 2 Always analyze Microcap results and determine if they make sense. There are some glitches in the program. Please note that the program assigns positive (+) and (-) ends to resistors and capacitors. Keep the (+) end connected to the expected high voltage side. Otherwise, the reported values will have the opposite sign. Introduction. In this part of the laboratory session your goal is to get acquainted with the use of Microcap. You will be drawing circuits, using the software to calculate the voltages at nodes and across circuit elements and to plot the time and frequency dependence of your circuits. The goal is not only to prepare the plots, but also reinforce the concepts of impedance, phase shift, filtering, and voltage amplitudes. Thus, it is important that you carefully examine these plots and understand them as a function of these concepts. 1. DC circuit. Calculate the voltages at nodes B, C, and E using the general principles and theorems given in class. Confirm your results using Microcap. There is no need to report these results. 30 k!+-A BE60 k!5 VD80 k!40 k! CF70 k!90 k!50 k! 2. AC circuit. Sketch the voltages at A and B as a function of time. Assume a frequency of 1 MHz. Compare your sketch with the plot obtained when you analyze this circuit with Microcap. There is no need to report these results. 3 k!A B3 k!C˜ 30 V 3. RC circuit. Sketch the voltages at points A and B as a function of time. Assume a frequency of 200 MHz. Compare your sketch with the plot obtained when you analyze this circuit with Microcap. Using Microcap, plot in the same graph the voltage drop across the resistor and the inductor as a function of time (i.e. VAB, VBC,Chem 8153 January 2009 3 respectively) and the source voltage. Using Microcap, plot in the same graph the amplitudes and phases of the voltage drop across the resistor and the inductor as a function of frequency. Report these graphs (with the three traces each). For the time plot include the VAB, VBC amplitudes, and the phase shifts. For the frequency plot include the breakpoint frequency. Make sure that you have 3-4 cycles in your graph. 3 k!A BC˜ 6 !F30 V 4. RL circuit. Sketch the voltages at points A and B as a function of time. Assume a frequency of 0.1 MHz. Compare your sketch with the plot obtained when you analyze this circuit with Microcap. Using Microcap, plot in the same graph the voltage drop across the resistor and the inductor as a function of time (i.e. VAB, VBC, respectively) and the source voltage. Report these graphs (with the three traces each). For the time plot include the VAB, VBC amplitudes, and the phase shifts. For the frequency plot include the breakpoint frequency. Make sure that you have 3-4 cycles in your graph. 3 k!A BC˜ 9 mH30 V 5. Resonance circuit. This type of circuits can selectively transmit or block a frequency. We have not covered this circuit in class yet, but Microcap can help you solve it now. Using Microcap, plot in the same graph the voltage drop across the resistor, the capacitor and the inductor as a function of time (i.e. VAB, VBC, respectively) and the source voltage. Report these graphs (with the four traces each). For the time plot include the VAB, VBC amplitudes, and the phase shifts. Report the resonance frequency. Make sure that you have 3-4 cycles in your graph.Chem 8153 January 2009 4 A BC˜ 1 V1 k!1 mH1 !F Report. In your report include the Microcap version used. The graphs requested in 3, 4 and 5 above. B. Designing your own circuit (When planning your circuit, keep in mind the power that can be dissipated by the components that you will be using). Introduction. In this part of this laboratory session you will select a few components, draw a circuit, solve it in Microcap, build the circuit on a Proto-board, and test the output of this circuit. Procedure. See the instructions and notes from the Experiment #1 when building and testing circuits. a. Find 5 components in the drawers. Include at least one resistor and one capacitor. Determine their values using a DMM. b. Draw a circuit of your own using the components that you chose. Select a measuring point and label it as A, B. See