1. INTRODUCTION
You are at the best, free online "Basic Electronics Course". Just read the brief blocks of text, view the videos, and check out some of the screened internet links. This is the easiest, fastest way to learn basic electronics. No sign-up requirements and it is free. The menu table above provides easy access to many interesting electronics topics. Print the menu table so you can check off the items as you study them and track your progress. You can enhance, expand and speed your learning by purchasing some of the book selections mentioned below. Take your time and enjoy.
Everyone today is exposed to electronic devices in one way or another. The computer revolution is a good example. Everyone can benefit from additional knowledge of electronics. Even a quick scanning of this page will help. A study of electronics starts with electricity, magnetism and basic electronics. This includes Ohm's law and other basic principles of electricity. Obtain and study various books on electronics - this is really a must as each author will explain things in a little different way to help you grasp the concepts.
All the internet links to other web sites found on 101science.com were screened to provide you with the BEST the internet has to offer on each subject. This will save you many hours of searching for good educational material. This site is for everyone from the beginner to expert electrical engineering professional. There is something here for every level of expertise in the world of electronics. If you just need information on one specific area, use the table above to navigate to the information you need. If you need more instruction - read on.
Maybe you already know some basic electronics and want to test yourself to see exactly how much you do know.
2. BASIC ELECTRICITY
ELECTRICITY AND MAGNETISM BASICS - It all starts with the electrons moving around atoms. Electricity is the movement of electrical charge from one place to another. Electric charges do not exist without their associated electric and magnetic fields. This module will introduce you to many of the basic concepts involved with electricity and magnetism.
MATTER - Matter is physically everything that exists that we can touch and feel. Matter consists of atoms. Now we will introduce you to the structure of atoms, talk about electrons and static charge, moving charges, voltage, resistance, and current. You will learn about the properties of magnets and how magnets are used to produce electric current and vice versa. All matter can be classified as being either a pure substance or a mixture. Matter can exist as either a solid, liquid, or a gas and can change among these three states of matter. In electronics the most important matter are conductive metals, non-conductive insulators, and semiconductors. (Yes, all this is a simplification on purpose to keep the subject easier to grasp. We will leave deeper thoughts to the study of nuclear physics.)
ELECTRICAL CHARGE - Any object or particle is or can become electrically charged. Nobody 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 10^18 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 (V). The unit of measurement of the current (I) or movement of the charge is called an ampere. The resistance, or opposition, to current flow is called an ohm (R).
3. BASIC ELECTRONICS
Now that you have a general background in electricity and moving charges you can move on to learning more about basic electronics. Electronics puts a knowledge of electricity to useful work. Electronics applies electrical current flow of electrical charges to circuits to accomplish specific tasks. Amplifiers can be constructed from glass "tubes" containing metal elements, or more commonly today with solid state diodes, transistors, or integrated circuits. An amplifier is simply a device or circuit that takes a small signal input and controls a larger current as it output. The input signal voltage is small and the output voltage is larger - amplified. A circuit containing wire conductors, resistors, capacitors, inductors and amplifiers can be configured in many ways to build various electronic circuits like oscillators, digital logic circuits, computer circuits, television and video circuits and much more. An oscillator by the way is just an amplifier with some of the output fed back into the input. Sounds like a perpetual motion machine but it isn't as the amplifiers power supply is providing the additional energy that is lost in the circuit and keeps the circulation, i.e. oscillations going.
Basic electronics is all about electrical components and the circuits consisting of those components . Common components are resistors, capacitors, inductors, transistors, and integrated circuits. You will find each of these components described in detail in the following numbered sections. The components are interconnect with conductors, either physical wires or printed circuits. The components make up linear analog amplifiers, oscillators, and filters as examples. They also can be configured to create digital logic circuits such as memories, gates, arithmetic units, and central processing units. So you will find basic electronics in every computer, mp3 player, radio, TV and may other appliances in your home, car, or on your body. Each circuit has a job. Components are interconnected to perform a specific task. First learn about each individual component and how it works then learn about how to interconnect them to make useful end products. Continue your study by reading the numbered sections to follow.
Get the Malvino books below if you need an easy to read but excellent book to learn electronics as a technician.
Testing Unknown Ferrite Cores
Ferrites are roughly divided into two groups. Those with permeabilities up to 850 are usually made from nickel-zinc material and have high volume resistivity ranging from 1x105 to 1x108. Higher permeability ferrites are usually made from manganese-zinc material and have volume resistivity ranging from 0.1x102 to 1x102. Iron powder cores are usually color coded and have very high volume resistivity. An initial test of the material can be made by checking the dc resistance between opposite faces/sides of a core. Low readings indicate a high permeability material. If you can measure inductance at a low frequency (10-100kHz), wind 10 turns of wire on the core and measure the inductance. You can then work back from the ferrite material formula and calculate the AL value, which can be compared with the tables of known cores of the same physical dimensions and so come up with a reasonable match. If 10 turns does not give a measurable reading try 20 or 30 turns.
RF power rating can be roughly checked by using two exactly similar cores each wound with the same primary and secondary turns (say 10 turns each on primary and secondary) and then connecting the cores back to back as shown. This arrangement provides a 1:1 equivalent so that the transmitter sees the correct load. Losses are doubled by using two transformers, but this does not matter for the test. Set the transmitter to the desired frequency and reduce the rf power output to a minimum. Increase the power output in small steps (say 5 -10W per step) holding each setting for 30 seconds then checking the temperature of each transformer. The transformers should only get warm to touch but NEVER hot. When the final temperature of each transformer has reached about 40 degrees centigrade you can say that you have reached the power limit for that particular core. Some cores will get hot at very low power. You have to make a value judgment about the core physical size versus the power rating achieved.
You are at the best, free online "Basic Electronics Course". Just read the brief blocks of text, view the videos, and check out some of the screened internet links. This is the easiest, fastest way to learn basic electronics. No sign-up requirements and it is free. The menu table above provides easy access to many interesting electronics topics. Print the menu table so you can check off the items as you study them and track your progress. You can enhance, expand and speed your learning by purchasing some of the book selections mentioned below. Take your time and enjoy.
Everyone today is exposed to electronic devices in one way or another. The computer revolution is a good example. Everyone can benefit from additional knowledge of electronics. Even a quick scanning of this page will help. A study of electronics starts with electricity, magnetism and basic electronics. This includes Ohm's law and other basic principles of electricity. Obtain and study various books on electronics - this is really a must as each author will explain things in a little different way to help you grasp the concepts.
All the internet links to other web sites found on 101science.com were screened to provide you with the BEST the internet has to offer on each subject. This will save you many hours of searching for good educational material. This site is for everyone from the beginner to expert electrical engineering professional. There is something here for every level of expertise in the world of electronics. If you just need information on one specific area, use the table above to navigate to the information you need. If you need more instruction - read on.
Maybe you already know some basic electronics and want to test yourself to see exactly how much you do know.
2. BASIC ELECTRICITY
ELECTRICITY AND MAGNETISM BASICS - It all starts with the electrons moving around atoms. Electricity is the movement of electrical charge from one place to another. Electric charges do not exist without their associated electric and magnetic fields. This module will introduce you to many of the basic concepts involved with electricity and magnetism.
MATTER - Matter is physically everything that exists that we can touch and feel. Matter consists of atoms. Now we will introduce you to the structure of atoms, talk about electrons and static charge, moving charges, voltage, resistance, and current. You will learn about the properties of magnets and how magnets are used to produce electric current and vice versa. All matter can be classified as being either a pure substance or a mixture. Matter can exist as either a solid, liquid, or a gas and can change among these three states of matter. In electronics the most important matter are conductive metals, non-conductive insulators, and semiconductors. (Yes, all this is a simplification on purpose to keep the subject easier to grasp. We will leave deeper thoughts to the study of nuclear physics.)
ELECTRICAL CHARGE - Any object or particle is or can become electrically charged. Nobody 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 10^18 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 (V). The unit of measurement of the current (I) or movement of the charge is called an ampere. The resistance, or opposition, to current flow is called an ohm (R).
3. BASIC ELECTRONICS
Now that you have a general background in electricity and moving charges you can move on to learning more about basic electronics. Electronics puts a knowledge of electricity to useful work. Electronics applies electrical current flow of electrical charges to circuits to accomplish specific tasks. Amplifiers can be constructed from glass "tubes" containing metal elements, or more commonly today with solid state diodes, transistors, or integrated circuits. An amplifier is simply a device or circuit that takes a small signal input and controls a larger current as it output. The input signal voltage is small and the output voltage is larger - amplified. A circuit containing wire conductors, resistors, capacitors, inductors and amplifiers can be configured in many ways to build various electronic circuits like oscillators, digital logic circuits, computer circuits, television and video circuits and much more. An oscillator by the way is just an amplifier with some of the output fed back into the input. Sounds like a perpetual motion machine but it isn't as the amplifiers power supply is providing the additional energy that is lost in the circuit and keeps the circulation, i.e. oscillations going.
Basic electronics is all about electrical components and the circuits consisting of those components . Common components are resistors, capacitors, inductors, transistors, and integrated circuits. You will find each of these components described in detail in the following numbered sections. The components are interconnect with conductors, either physical wires or printed circuits. The components make up linear analog amplifiers, oscillators, and filters as examples. They also can be configured to create digital logic circuits such as memories, gates, arithmetic units, and central processing units. So you will find basic electronics in every computer, mp3 player, radio, TV and may other appliances in your home, car, or on your body. Each circuit has a job. Components are interconnected to perform a specific task. First learn about each individual component and how it works then learn about how to interconnect them to make useful end products. Continue your study by reading the numbered sections to follow.
Get the Malvino books below if you need an easy to read but excellent book to learn electronics as a technician.
Testing Unknown Ferrite Cores
Ferrites are roughly divided into two groups. Those with permeabilities up to 850 are usually made from nickel-zinc material and have high volume resistivity ranging from 1x105 to 1x108. Higher permeability ferrites are usually made from manganese-zinc material and have volume resistivity ranging from 0.1x102 to 1x102. Iron powder cores are usually color coded and have very high volume resistivity. An initial test of the material can be made by checking the dc resistance between opposite faces/sides of a core. Low readings indicate a high permeability material. If you can measure inductance at a low frequency (10-100kHz), wind 10 turns of wire on the core and measure the inductance. You can then work back from the ferrite material formula and calculate the AL value, which can be compared with the tables of known cores of the same physical dimensions and so come up with a reasonable match. If 10 turns does not give a measurable reading try 20 or 30 turns.
RF power rating can be roughly checked by using two exactly similar cores each wound with the same primary and secondary turns (say 10 turns each on primary and secondary) and then connecting the cores back to back as shown. This arrangement provides a 1:1 equivalent so that the transmitter sees the correct load. Losses are doubled by using two transformers, but this does not matter for the test. Set the transmitter to the desired frequency and reduce the rf power output to a minimum. Increase the power output in small steps (say 5 -10W per step) holding each setting for 30 seconds then checking the temperature of each transformer. The transformers should only get warm to touch but NEVER hot. When the final temperature of each transformer has reached about 40 degrees centigrade you can say that you have reached the power limit for that particular core. Some cores will get hot at very low power. You have to make a value judgment about the core physical size versus the power rating achieved.
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