Discover Electronics

Lesson 1

Ariel Churi — Sat, 23 Oct 2010 14:23:03 +0000

With lesson one the idea is to get familiar with some of the basic concepts and terminology as well as the solderless breadboard.

Electrical Pressure

Ariel Churi — Fri, 22 Oct 2010 15:18:50 +0000

All matter is made of atoms. Atoms are made up of tiny particles we call electrons, protons and neutrons. Protons and, usually, neutrons form the center (nucleus) of the atom. Electrons spin around the nucleus.
All matter is made up of these few parts. It is only the number and arrangement of the particles that makes one type of matter different from another.

These particles can have an electrical charge. Protons have a positive electrical charge and electrons have a negative electrical charge. Positive and negative are attracted to one another while like charges repel one another.

Lithium Atom

The electrons spin in different levels called electron shells. Electrons in the smaller/closer electron shells have less energy then electrons in the further/larger shells. Electrons and protons usually balance out so the overall electrical charge of an atom is neutral. Not positive or negative.

If the protons and electrons are out of balance the atom has an electrical charge. An atom with more electrons then protons has a negative electrical charge. Electrons can move from one atom to another because it is attracted to positively charged atoms and repulsed by negatively charged atoms.

Conductors are materials that conduct electricity well. Conductors, like a copper wire, are made up of atoms that gain and lose electrons easily. Allowing the electrons to be passed down the wire. Insulators are materials that do not allow electrons to move easily, like the rubber coating on your copper wire.
The electrons actually move down the wire quite slowly. As they move they repulse the electrons in front of them creating a wave of repulsive force which moves down the wire very quickly.

These electrons can have a number of different effects as they move. The can bump into atoms on the way and cause them to move around which is heat. They can move up and down the electron shells of atoms. If they move down to lower energy shells they give up the excess energy in the form of photons (light). They also create invisible electromagnetic waves as they travel. These waves can create electric current in matter that they touch as well as create motion by the attraction and repulsion of magnetic waves.

We use all of these properties of electrons in different ways. We create heat to cook food and keep us warm. We create light to see by. We create motion to turn fans and push trains. We also use it to send and receive information. We can use electricity to send information through the wires or create electromagnetic waves to send information through the air.

Stay tuned for the next article in our series where we will talk about electric voltage, current, and resistance.

Solderless Breadboard

Ariel Churi — Fri, 22 Oct 2010 15:17:16 +0000

Powering your breadboard with the 7805

Ariel Churi — Fri, 22 Oct 2010 15:16:44 +0000

Further Learning:
Linear Regulators on Wikipedia

Your First Circuit : The LED Driver

Ariel Churi — Fri, 22 Oct 2010 15:14:55 +0000

Further learning:
Wikipedia: LED circuit

Volts, Amps, and Ohms

Ariel Churi — Fri, 22 Oct 2010 15:13:42 +0000

An electrical circuit allows electrons to flow from one side of the circuit to the other. The two ends of the circuit have a difference in electrical charge. One side is more positively charged then the other. Electrons are attracted to the positive side and move through the circuit. The electrons move from the negative side of the circuit to the positive but we say the electrical current flows from the positive to the negative. It is the attractive force emanating from the positive side of the circuit that we call the current.

This diagram shows a simple LED driver circuit. When the battery is connected the positive end of the battery pulls electrons from the negative end of the battery and through the circuit. This circuit has three basic properties we can use for measurement and analysis. They are voltage, current, and resistance.

Voltage
The amount of difference in electrical charge between the two sides of the circuit is called the voltage. Higher voltage power sources will have more attractive force. Voltage can be considered electrical pressure pulling electrons through a circuit.

Current
While the voltage moves the electrons through the circuit they cannot all go at once. The rate at which the electrons move through the circuit is called the current. We measure the current in amperes. One amp is about 6.241×10¹⁸ electrons passing through a point in a circuit in one second.

note: 6.241x10¹⁸ is an easier way to write a big number. It stands for the number 6,241,000,000,000,000,000.

Resistance
Because of the electrical pressure the electrons would like to move at a very high current but some materials conduct electricity better then others. Materials that have a high resistance conduct electricity less well. Resistance limits the flow of electrons between the two ends of the circuit. We measure resistance in units called ohms (Ω). One ohm is defined as the amount of resistance you have in a conductor when applying one volt of electrical pressure creates one amp of current.

So lets’ recap. Voltage is like electrical pressure. It is the amount of difference in charge between the two sides of the circuit. Current is how quickly the charge moves from one side to another. Resistance holds back the electrical pressure, impeding the current. Higher voltage creates high current. High resistance causes lower current.

Troubled Circuits

Ariel Churi — Fri, 22 Oct 2010 07:18:48 +0000

Comment on the Troubled Circuits section here.

Light Emitting Diode

Ariel Churi — Thu, 21 Oct 2010 20:09:13 +0000

Futher learning:
MAKE presents: The LED
LED circuit tutorial
Notes on LEDs at Gizmology
The Electronics Club: LEDs
TheLEDlight.com: LED basics

Resources:
LED calculator

Lesson 2

Ariel Churi — Mon, 27 Sep 2010 21:16:29 +0000

For this lesson we continue to get familiar with the basics of volts, amps, and ohms. We will look at a voltage divider, the difference between series and parallel, and Ohm’s law.

It is probably best to review some of the previous videos before continuing.

Welcome to the Discover Electronics online course.

Ariel Churi — Tue, 21 Sep 2010 13:20:37 +0000

This course is an introduction to hobby electronics with a focus on building your own small projects. It is part of the Discover Electronics kit available here.

To take full advantage of this course watch some of the videos all of the way through before you start. As the course progresses I will add more resources to this site as well as assignments for you to complete.
The course group has a forum as well as a documents section that we will use for additional materials. In your profile you will find a place to upload photos you would like to share.