There's electrical engineering and electronic engineering and cross-breeds, such as electro-mechanical engineering. They are all different, and yet all the same.
The sameness comes from the fact that engineering is about making things happen. Science, gives us theories and proofs and data. The real world of work and industry sets us problems and challenges.
The job of the engineering team is to use a bit of science, a bit of creativity and a lot of hard work to create machines, systems and structures which overcome those problems and meet the challenges—all within the specified time and budget, and in reasonable safety.
So electrical engineering is about overcoming challenges which involve things measured in volts, ohms and watts—or more commonly, kilovolts and megawatts. Electrical engineering is usually about shifting energy and power from one place or function to another, with as little loss as possible.
Electronic engineering is also about stuff measured in volts, ohms and watts, but more often, these things are measure in microamps and milliwatts, and the important thing is to convey information, rather than raw power. Like electrical engineering, the engineers try to minimise the losses—and again, all this has to be done at reasonable expense.
A lot of people think an engineer's job is about making stuff work. That is true, but the bigger task is making it work, within a budget. It is easy to make anything work, if you have unlimited time and money. The trick is to do it at minimum cost, so that it is economically viable, and the skill is in judging what costs and corners can be cut without affecting the overall functionality.
And the costs are broken down into initial capital costs of the basic system, and running costs. More sophisticated models look at total cost of ownership (initial cost, plus cumulative running costs, repair costs, etc). The best designs minimise total cost of ownership, while maximising the functionality.
One of the first things an engineer learns is that all engineering is about compromises. The job is to balance costs and time against functionality. If you want a system to do more, it usually takes more time to design, and it usually costs more. Not always, though, and that's half the fun of engineering: trying to find things which are cheaper, quicker and better.
An electrical engineer will be involved in the design and construction of any system where there are currents of more than a hundred amps or so, or where the voltages typically rise above a few kV, or where the electrical supply is based around the industrial three-phase standard. These might include the following types of object (and many more):
One of the special skills an electrical engineer needs is the ability to reduce the amount of real power and imaginary power used. Reducing real power is obvious: the less power used, the less it all costs. But it is even more important to reduce the imaginary power. Although it seems a bit counter-intuitive, some circuits—especially those with large coils of wire, such as motors—will consume only small amounts of real power (measured in watts) yet, they operate at huge currents and voltages. The imaginary power (measured in VARs –Volt-Amps reactive) does not create heat, but nevertheless, the currents are very real, and will be charged by the electricity supply company at the normal rate—or sometimes above normal, as this reactive power is difficult to balance in many power circuits.
Another skill is load balancing. Most domestic circuits use a single phase supply, which requires a live, a neutral and an earth line. Industrial circuits by contrast use a three-phase supply, which has three live lines and a return. Just as in a domestic supply, the earth should carry no current, in a three-phase supply, the return line should not carry any current, because the vector sum of the three phases is (or should be) zero. However, if the load on each of the three phases is not correctly balanced with the other phases, then the return line will carry some current, and this is wastefuland can be dangerous. Ensuring that the load on each of the three circuits is balanced both in terms of real load, reactive load and across time is a special skill.
Mathematics: the Swiss army knife of the professional engineer. One cannot succeed at any type of advanced engineering without a thorough knowledge of mathematics. However, the focus is very much on applied mathematics. For instance, differential equations are essential for solving problems related to electrical and magnetic fields. Vector analysis is important for load balancing and phase calculations. Vector field theory very important in broadcasting systems, for example.
Electromagnetic theory: This is the fundamental science of how electrical fields and magnetic fields interact and propagate. A good understanding of electromagnetism is absolutely essential for anyone wanting to work with rotating machinery, power lines, transformers or other systems involving large currents and voltages.
Rotating machinery Electrical engineering grew out of the design of motors and generators. These are lumped together under the common term, rotating machines, because they all involve spinning coils and magnetic fields and moderately large current densities.
Analog circuits: An essential course for anyone intending to use or create conventional electrical and electronic circuits. It covers the basic theory of how voltages and currents get split up when faced with multiple current paths. It also covers individual components like resistors, capacitors, inductors, as well as more modern components such as diode and triode valves, and transistors. This enables students to calculate the theoretical voltages and currents at any point in the circuit, at any given time, and to allow for real-world variations from the theoretical analysis. Analog circuit analysis is divided into steady-state conditions, and transient conditions, such as at switch-off and switch-on. Transients are much more difficult to analyse.
Digital circuits: Another fundamental course, but this one covers the analysis and design of digital circuits, where current flows are less important that voltages. In a digital circuit, the signal can only take one of two values: on or off. The on state is usually represented by a voltage above about 2V aor 3V, while the off state is usually represented by a voltage below about 1.5V. Digital circuit design includes Boolean logic, and the use of the various logic gates described by expressions such as Nand, Or and Not
Information theory: This is a fundamental science, but is often not well understood. In modern thinking, information theory is primarily concerned with ways to transmit and store a piece of information using the minimum data. Information is the stuff our brains need to trigger a thought or idea—such as a picture. Data is the digital stuff we need to represent the information—such as a JPG computer file. Information theory attempts to describe how much data we need to satisfactorily describe the information to an appropriate level. As noted above, the engineer's job always involves compromise, and while it is expensive, or slow to transmit or store images, information theory allows us to use the minimum bandwidth while delivering as much useful information as possible. MP3, DVD disks and the JPG format are all triumphs of data compression, made possible only by sophisticated information theoreticians.
Signal processing: Again, a required course for anyone involved in transmitting data or information, and closely wrapped up with information theory. Signals always degrade with time and distance. It is a fundamental fact of life. The signal processing unit attempts to show how we can improve a signal by filtering or other enhancement. The idea, at its most fundamental, is to find methods of extracting the maximum information from impure, damaged or corrupted data. Anyone who has used the SETI@homesoftware is watching some very sophisticated signal processing in action.
Control theory: this topic deals with how to make your machine do what you want it to do. A simple example is the cruise control on your car. Set the cruise control and the control system allows more fuel into the engine as you ascend a hill, and restricts the fuel as you descend the other side, in order to maintain a constant speed. The amount of fuel is governed by a relatively simple control algorithm. Control theory is all about how to set the parameters of such systems, how sensitive to make them, how to know when they might become unstable and how to deal with it when they do. Control theory is heavily mathematical, but quite beautiful in the way it describes all sorts of natural and manufactured systems.
Many other courses: there is simply not enough space to list all these courses in detail, but a few that the prospective engineer might come across include: Technical drawing, probability, programming, non-linear systems, risk analysis, economics, mechanical engineering laboratory, VLSI design...
The distinction between electrical engineering and electronic engineering is growing less obvious with time. Over the last 10 years or so, it has become much easier to implement ideas and designs using standard, off-the shelf digital hardware than to create a standard analog circuit. It has become easier to build a control system in software, and apply it to different types of hardware. It has become easier to model a nation-scale electrical power distribution system on a standard workstation, and then test it as a virtual entity, than to build a physical test rig.
Unlike the chemical engineers the electrical engineer is not often in charge of a major ($100 million) project, more often he or she ihas a part of the project to run. In the case of a power station, the architects and civil engineers would have overall control of the project. In the case of a chemical plant, the chemical engineer would bring the electrical engineers in when looking at the overall power requirements of the plant.