A dipole is an electrical conductor with two poles (also called terminals). An electric circuit is an association of dipoles connected to one another by conducting wires.

In order for a current to flow in the circuit, one of the dipoles must be a source of current (generator) and the circuit must be closed.

• Two dipoles are in series when they share only a single terminal and, between  shared terminals, there is no branching toward another dipole.
• Two dipoles are in parallel (or in a branched circuit) if their two pairs of terminals are shared.

An electrical circuit consists of :

• At least two components (also called dipoles because they have two poles) one of which is the generator (also referred to as the source).
• Conducting wires that connect the components to form a closed loop that enables current to flow.

Numerous forms of transpoort operate using electrical energy. Regardless of the dipole used, an electric motor is connected to the generator (not shown in the photos) by two conducting wires.

The electric power available at the terminals of a dipole is equal to the product of the current (I, in amperes, or "amps") and the voltage (E, for "electromotive force", in volts).

Remark: The colors chosen are not the conventional ones. The voltage and the current  could be direct or alternating.

An electric diagram uses symbols to represent the circuit. It shows how the parts of the real circuit on the left are connected.
All the devices must be connected without any break for electric current to flow around the circuit.

The total electric force experieced by a single charge at a point is equal to the vector sum of the forces due to each source charge. This is the superposition principle.

The total electric force experienced by a single charge at a point is equal to the vector sum of the forces due to each source charge. This is the superposition principle.

This sliding array shows the great differences in the resistance values of conductors and insulators. The superconductors included in the animation are not new elements, but represent a physical phenomenon observable under certain conditions.

This animation  illustrates a  common classroom demonstration of  electrostatic effects – that is, the movement of charges in a conductor as an electrostatic charge is brought near it, as well as when a conducting path is put in contact with the original conductor.  The illustrations include force at a distance,  polarization, the effects of electric fields, electric neutrality and the properties of conductors.

Click on the 'field' button to make the lines of force visible. You will see the field created by the fixed charge at any point, whether or not there is a test charge (blue vector). A force will exist only if you place a charge on this pre-existing electric field (Remember a charge never experiences its own electrical field).

Click once on the screen at the point where you want a positive test charge to be. You will then see the force experienced by this test charge (red vector). According Coulomb's law, the field is function of the distance to the fixed positive charge (the force as well)

Click a second time to release the test charge. The charge is then accelerated outward.

Click once at the point where you want a positive test charge to be. The force will appear in blue. It depends on the distance to the fixed positive charge. Click a second time to release the test charge. The charge is then accelerated outward.

The typical trajectory of the test particle is an ellipse similar to gravitational orbits. Click on the moving charge to catch it, then “throw it” to create new initial conditions.