Electrical engineers design and build electrical circuits, install and maintain electrical wiring, and repair damaged electrical components. The field of electrical engineering contains many neologisms and jargon, as well as familiar words used in a specific sense.

All engineering disciplines deal with physical quantities and use units to measure those quantities. In electrical engineering the main quantities are charge, current, voltage and resistance. These are measured in coulombs, amps, volts and ohms respectively. Charge is the property of being electrically charged. Current is a flow of electrical charged particles. Voltage is the potential difference caused by two areas of differently charged material. Resistance describes a material's resistance to the flow of current.

In addition to the basic and familiar wires, batteries and light-bulbs; electrical engineers use a wide range of less well-known electrical devices. These include resistors, capacitors, inductors, diodes and transistors. Resistors are simply sections of wire with particular known resistances. Capacitors store energy in an electrical field. Inductors store energy in a magnetic field. Diodes allow current to flow in one direction only. Transistors are electronically controlled switches that enable the functioning of modern digital computers.

Tools specifically used by electrical engineers include voltmeters, ammeters, soldering irons and oscilloscopes. Voltmeters measure the voltage, also known as the potential difference, between two points in an electrical circuit. Ammeters measure the flow of current in a circuit. Soldering irons are used to join electrical components using a molten metal. Oscilloscopes are used to detect and display signals in electrical circuits.

There are a number of fundamental formulas used in electrical engineering. One of these is Ohm's Law. This states that for an Ohmic conductor the voltage between two points in the conductor is equal to the product of the current and the resistance. Another way of saying this is "V = IR." Another important formula is "P = IV." This means that electrical power is equal to the product of current and voltage.