Magnetism and Electromagnetic Devices

Magnetic Attraction and Repulsion

Magnetism and Electromagnetic Devices In this section, you will learn about basic magnetism and electromagnetism. Three important electromagnetic devices are introduced: the relay, the generator, and the motor. All of these devices are important in renewable energy systems. Relays are commonly used in many applications to switch current on and …

Read More »

Conductors, Insulators, and Semiconductors

Electricity consists of moving charge. When we think of the path for electricity, we think of wires most of the time. In metallic solids, electrons make up the charge that moves; however, the charge can also move through certain liquids and gases as well as space itself. In this section, …

Read More »

Series and Parallel Circuits

Four Examples of Parallel Circuits 1

Series and parallel circuits are two basic arrangements of the source and loads. Series and parallel circuits are often combined to form complex circuits that can be understood on the basis of simpler series and parallel arrangements.  Series Circuits A series connection is one with a single path. A series circuit has …

Read More »

Power and Watt’s Law

Watt Law

When there is current through a resistance, electrical energy is converted to heat or other forms of energy such as light. A common example of this is the incandescent light bulb that becomes too hot to touch when it has been on for a short time. The current through the …

Read More »

Resistance and Ohm’s Law

Cutaway View of a Carbon-Composition Resistor

With the exception of a special class of materials called superconductors, all materials have resistance, which is the opposition to current. Conductors are generally metallic materials with low resistance, whereas insulators are materials with high resistance. When there is current through a resistive material, heat is produced by the collisions …

Read More »

Electrical Current: Definition & Formula

Complete DC Circuit

The original idea of current was based on Benjamin Franklin’s belief that electricity was an unseen substance that moved from positive to negative. Conventional current is defined based on this original assumption of positive to negative. The original definition is widely used, although there is another definition of current called electron flow. Electrons move …

Read More »