Digital Logic

Keep in mind that computers work on an electrical flow where a high voltage is considered a 1 and a low voltage is considered a 0. Using these highs and lows, data are represented. Electronic circuits must be designed to manipulate these positive and negative pulses into meaningful logic.

Logic gates are the building blocks of digital circuits. Combinations of logic gates form circuits designed with specific tasks in mind. For example, logic gates are combined to form circuits to add binary numbers (adders), set and reset bits of memory (flip flops), multiplex multiple inputs, etc.

ELECTRICITY AND MAGNETISM BASICS - This module will introduce you to many of the basic concepts involved with Electricity and Magnetism. We will introduce you to static charge, moving charge, voltage, resistance, and current. You will be able to discover Ohm's law. We will learn about the properties of magnets and how magnets are used to produce electric current. Exactly what is electricity?

Any object or particle is or can become electrically charged. No one completely understands what this charge consists of but we do know a lot about how it reacts and behaves. The smallest known charge of electricity is the charge associated with an electron. This charge has been called a "negative" charge. An atoms nucleus has a positive charge. These two un-like charges attract one another. Like charges oppose one another. If you had 6,250,000,000,000,000,000 electrons in a box you would have what has been named; one coulomb of charge. An easier way of thinking about a large number like that is called "powers of ten" and it would look like this 6.25 x 1018 electrons. It is simply a way to let you know to move the decimal point to the right 18 places. When electrical charges are at rest, meaning they are not moving, we call that static electricity. If charges are in motion we then have a flow of charge called electrical current. We have given the force that causes this current a name called electromotive force and it is measured by a unit called a volt. The unit of measurement of the current or movement of the charge is called an ampere. The resistance, or opposition, to current flow is called an ohm.

Around a charge is an electric field. With every electric field there is a magnetic field. While we can't see these fields, or yet know exactly what they consist of, we can measure them with instruments and tell a great deal about their behavior. We can then use this knowledge to our benefit. The design and construction of electric motors, computers, radios, televisions, stereos, and many other electrical and electronic devices depend upon a knowledge of these basic principles of electricity. As you can see we have given names to these phenomenon to make it easier for us to study and use. We could have called them Dick, Jane and Mary but instead we named them for the scientists that discovered or first studied them; Volt, Ampere, and Ohm. Mr. Volt, Mr. Ampere, and Mr. Ohm spent many years of their lives studying electricity. They were not alone however as many other scientist were studying and learning more about electricity as well.

Electric Circuits - Basic & Advanced

Direct Current (DC) Electricity

Direct current or DC electricity is the continuous movement of electrons from an area of negative (−) charges to an area of positive (+) charges through a conducting material such as a metal wire. Whereas static electricity sparks consist of the sudden movement of electrons from a negative to positive surface, DC electricity is the continuous movement of the electrons through a wire.

A DC circuit is necessary to allow the current or steam of electrons to flow. Such a circuit consists of a source of electrical energy (such as a battery) and a conducting wire running from the positive end of the source to the negative terminal. Electrical devices may be included in the circuit. DC electricity in a circuit consists of voltage, current and resistance. The flow of DC electricity is similar to the flow of water through a hose.