Simulation Of Analog And Digital Circuits With The Electronic Workbench

The improvement of software to simulate electrical circuits has been tremendous in recent years. The new version of Electronic Workbench for Windows (EWB 4.0) is a user friendly simulation program [1]. This paper will focus on providing information on how to use the EWB 4.0 simulation software in the classroom. Students can use this program to design and simulate their Analog, and Digital circuit assignments prior to actual building of the circuit(s) in the laboratory. This paper intends to familiarize the reader with simulation software, in particular, with the Electronic Workbench for Windows version 4.0. Introduction: We will first explain the commands, and the method of drawing an electric circuit on the EWB 4.0 screen. Then, we will describe the Component Icon groups, and the Instrument Icons. Five examples will show the convenience and the speed of Electric and Electronic circuit simulations. In the first example we will discuss the use of a function generator, oscilloscope, multimeter, ammeters, and voltmeters to supply and display AC and DC signals. The second example will be a two-stage amplifier with a voltage gain of two. In the third example, the Bode Plotter will be used to display the magnitude, and phase shift of a notch Operational Amplifier (Op-Amp) filter. In the fourth example, the Logic Converter is used to construct a Combinational Logic circuit from a Truth Table. Next, we will use the Word generator, and the Logic Analyzer to display the Timing Diagram of the digital circuit. Finally, in the last example, we will analyze a Sequential and Hybrid Logic circuit. Also, we will show how to simulate four-way switches using single-pole, single-throw (SPST) switches. Analog Circuit Simulation: We select the components by clicking on the component and dragging it to the desired position on the screen. We may use the Circuit command to select the appropriate component group prior to the component selection. Once we have placed the components on the circuit, we should connect wires to complete the circuit. Click on a node of a component, and drag the mouse over to a node on another component. The two components will connect. 1 Double click on the wire, and select the color for that wire. Note that we use different wire colors in order to have multicolor signals on the Oscilloscope. After completing the circuit, we are ready to use the instruments available in the software to analyze the circuit. Figure 1 displays the Electronic Workbench’s analog instruments. ~ .,,,> {~~j 1996 ASEE Annual Conference Proceedings ‘O$lylly P ge 188.1 Figure 1. The Analog Instruments Several AC/DC Voltmeters, and Ammeters can be used in a circuit, but there is only one Multi-meter available to be used. “Double Click” on the instrument to expand its Icon, in order to see the function buttons on the instrument. Figures 2 through 5 display the Multimeter, the Function Generator, the Oscilloscope, and the Bode Plotter, respectively. Note that the Instrument’s functions emulate very closely the actual instruments. Figure 2. The Multimeter Figure 3. The Function Generator ?$!iii’ } 1996 ASEE Annual Conference Proceedings ‘.,,<~ym’,.$ P ge 188.2