1. Chapter 5 Engineering Tools for Electrical and Computer Engineers

2. Introduction  Many tools are available for electrical and computer engineers in their everyday work.  These tools include meters used to measure voltages, currents, field strengths; oscilloscopes used to view waveforms, and a variety of computer based software and hardware.

3. General Ideas and Safety Considerations  When working with electrical equipment safety should have the uppermost priority.  Mistakes or carelessness pose danger to the user and others, and may damage expensive equipment delaying the completion of the project or experiment.

4. General Ideas and Safety Considerations  When dealing with new equipment you should start by studying the operation manual.  This first step ensures that the type of measurement being attempted is possible with that instrument  You should determine the maximum levels of voltages and currents that can be applied to the instrument and, that the values expected in the experiment do not exceed these maximum values.

5. General Ideas and Safety Considerations  When connecting a circuit it is safest to ensure that the power source is connected last and disconnected first.  When dealing with DC circuits it is standard to use red wires for positive voltages and black wires for negative voltages.  Never assume that a circuit is dead just because the switches are off, mechanical switches may be damaged causing serious injury to the user or even death.

6. General Ideas and Safety Considerations  Use a voltage meter every time to make sure that the voltage is what you expect it to be.  The application of the measurement instrument introduces error to the quantity being measured.  It is the responsibility of the person taking the measurement to know the characteristics and limitations of the measuring instrument to be able to predict the amount of error it introduces to the measured quantity.

7. Meters  Meters used in measuring electrical quantities include analog and digital types.  Analog meters are read by noting the position of a needle on a scale.  Newer meters are digital, these have numerical or digital readouts.  The most common type of meters is VOM meter, this reads voltage, resistance, and current.

8. Meters  The quantity being measured and the range are adjusted by knobs on the face of the meter.  It is important to choose the proper range for the quantity being measured, to avoid burning the meter it is best to start with the maximum range and go down to the proper range.  Cheaper instruments are expected to introduce larger errors.

9. Oscilloscopes  An oscilloscope is used to observe time-varying voltages or currents on a screen.  Computers can also be used as virtual oscilloscopes when equipped with the proper hardware and software.  There are many controls on an oscilloscope, so it takes practice before you master it.

10. Computers  Computers can be used to control electrical test equipment such as meters and oscilloscopes, they can also be used to record measurement parameters and test data.  Computers can be used to coordinate the activities of several test equipment tools through a local network, this would require writing a simple program to interface the computer and the test equipment.  Computers can be used as virtual instruments.

11. Application Software  Software tools are used to aid in designing new devices, analyzing the operation of existing devices, and to help with tasks such as data analysis.  Following are some types of these tools.

12. Problem Solving Software  These help in solving complicated problems with matrices, complicated integrals, and large systems of simultaneous linear equations.  These include packages such as: MATLAB, MATHCAD, Mathematica, MAPLE.  Advanced software packages can do image processing, signal processing, control system design.

13. Circuit Simulation  Circuit simulators allow an engineer to enter all the circuit components and interconnections to a computer program.  The program collects data about how the circuit operates and all the output and parameter values involved, and predicts the behavior of the circuit when a certain parameter is varied, it also provides plots for the outputs.  Examples of these programs are Pspice, EWB.

14. Data Acquisition and Control  When testing the performance of a circuit or system. The parameters of the circuit need to be set and meters connected, the data is then recorded and the parameters are changed and new data recorded, finally graphs of this data are produced to help understand the results. Doing this manually is tedious and takes a long time.  Data acquisition software such as LABVIEW, the test equipment is connected to a computer, the program then does all the tasks describe above in a much shorter time.

15. Spreadsheets  Spreadsheets can import data generated in experiments and perform calculations on that data.  The data can be exported from spreadsheets to other applications to plot them or do further processing.  Excel, Lotus123 are examples of spreadsheet softwares.

16. Databases  Database software such as Access, are used to store large amounts of information, label it according to one of its attributes, and then retrieve the information according to these labels.  They also allow for graphing of the data and aid in the preparation of reports.

17. Graphing  Plots of data can be very helpful to an engineer in understanding and predicting the behavior of their devices.  MATLAB has powerful graphing capabilities.  Some plotting software allow for graphing special types of plots such as Smith charts used in electromagnetics to plot the behavior of the transmission line.

18. Word Processing  Engineers are often required to communicate their ideas and their work in the form of written reports.  Word processors such as Word or WordPerfect allow them to easily compose and edit documents, and produce high quality printout, graphs and tables generated by other software packages can be easily imported and pasted into the word processor.

19. Presentation Preparation  Engineers are often required to make oral presentations of their work.  Software such as Powerpoint help in producing high quality, visually exciting presentations.  It is also possible to import graphs, pictures in other software packages to combine them in the presentation.  These programs can also run projectors that display the presentations.

20. Programming languages  An engineer must master one or more of the available high-level languages to be able to write a program for performing the different tasks encountered in his line of work.