|Basic Electronics Cliffnotes|
|Written by Edvin Eshagh|
The entire Universe is composed of "matter"
The very force that holds matter together has an "electrical" nature
An "element" is the basic building block of matter found in the periodic table. There are more than 92 of them known today
An "attom" is the smallest piece of an element that still retains the characteristics of the element
The smallest possible amount of an element would be an "atom"
According to the video "Principles of Electricity", the size of an electron is 100 feet, compared to an atom as big as the United States (3000 miles or 16,000,000 feet wide).
The atomic nucleus has "positive" charge
A "balanced or nutral" atom has the same number of electrons as protons
The establishment of "balanced" charges is the principle of the generation of electricity.
In a copper-zinc cell (battery), when the zinc is placed in the chemical solution, some of the zinc atoms go into the solution leaving behind some of their "electrons"
Unbalance of charge is cause of electricity (electric current)
Work done by electricity requires a flow of current
3 primary factors that effect the flow of electricity : 1) voltage 2)current 3)resistance
An excess of electrons at one end of a conductor such as a wire and/or a deficiency at the other end creates a kind of electrical pressure and is often called a "potential" difference
The Unit of electrical pressure or potential difference is the "volt"
The flow of electrical charge is called "current"
One ampere of current is a "6 billion 300 million billion (6.24x10^18)" electrons passing a point in a second. This number is called a coulomb.
Current (or amperage) is the number of electrons that pass by a point in a given time
Resistance is the collision of electrons with atoms in a conductor, causing heat
Electrical pressure is the urge of unbalanced charges
Conductorts have a large number of free electrons
Conductors: iron, aluminum, silver, copper
Insulators: rubber, plastic, glass, dry wood, ceramics
electrons are not free to move around like in a metal, they have to stay with their atoms
Electrons are free to move around in a metal among the atoms
Difference between conductor and insulator is the availability of free electrons
Unit of resistance = ohm
"Electromagnetic generator" is the "workhorse" that pushes electrons through wires using magnetism, and supplies most of our electricity
Electrons act like tiny magnets
Groups of electrons in a material that point their magnetic fields all in the same directions are said to form a "domain"
Materials like copper in which electrons cannot be aligned are called "non-magnetic" materials
number of electrons in outermost shell most effects electrical characteristics of an element
To this day it is conventional to speak of electricity as flowing from positive to negative, even though it is known that electrons move from negative to positive
AWG = American Wire Gauge
cross sectional area in circular mils of a wire 10 mils in diameter is 100 circular mils
Glass + Silk attracts Wax+wool
Rubber ballon + Cloth, fur, hair
When rubbing a piece of wax with a piece of wool, the wax became "negative, while the wool became "positive"
Some early electrical experimenters speculated that "invisible fluids" were being transferred from one object to another during the process of electrification, and that they were able to effect a physical force over a distance
"Charles Dufay" is famous for discovering and demonstrating that there were two types of changes created when rubbing certain pairs of objects together.
The hypothetical fluid that caused objects to attract or repel each other when it was transferred became known as "charge"
"Ben Franklin" came up with idea that electricity behaved like a single fluid transferred between objects
all matter around us contains electricity in the form positive and negative charge
Charles Coulomb did experiments to measure the
The unit of electical charge is "coulomb"
The name of the "electron" and the word "electronics" is derived from "a Greek term for hardened tree sap"
The attraction of the electrons toward the protons in the nucleus Keeps the electrons in orbits within the atom
There are microscopes that use electrons instead of light to make images of atoms
Type of element an attom is, is determined by the number of "protons" contained inside its "nucleas"
ion - an atom with too much or too few electrons
Atomic nucleas has postive charge
compound - chemical combination of different kinds of elements. Smallest peace of molecule
Compound - 1) Carbon Dioxide (CO2), 2)Sufuric Acid (H2S04), 3) Water, 4) Protien
Water is NOT an element on peridic table
In periodic table: oxygen, silicon, hydrogen, lithiumm, carbon
Pure element form: liquid, gas, solid
atomic number (weight) - Type of element that an atom is, is determined by # of protons in nucleus
1836 electron weigh as much as proton
isotopes - Atoms of the same element with same number of protons in the nucleus but with different numbers of neutrons
Ionization is caused by: light, firction, radiation, electrons
More energy required to ionize an atom of a given element, as you move to the right in the periodic
valence shell - outermost electron orbit -
Conductive materials have a large number of free electrons
superconductors - Perfect condutors at low temperatures
net movement of more electrons in one direction than other directions is electric current
Basically, electricity is the flow of electrons through a conductor
The invisible force field around a charged body is called an "electic field"
matter - anything that occupies space and has weight
Voltage is defined as the measure of the "work" required to move a unit of "charge" from one location to another against the "force" that tries to keep the charges "balanced"
Source of voltage:
Columb = The electrical charge carried by 6.24 x 10^18 electrons
I = Current
DMM = A digital multimeter
three parts of a basic electric circuit: Voltage source, conductors, load
Power - the rate that energy is used over time
Piezoelectric effect - Some crystals will produce a voltage when they subjected to pressure
Photovoltaic cell - generate electricity via light
Zinc-carbon batteries provide 30 watt-hours per pound versus 45 watt-hours per pound for the more expensive alkaline batteries
Secondary voltage source are typically rechargeable batteries, which can include Nickel-Cadmium (Ni-Cad) batteries, Nickel-Metal Hydride (NiMH), lead-acid
Mutual induction - a changing magnetic field due to one coil creates a current in a nearby coil
ferromagnetic - Materials whose atoms can arrange themselves in domains when influenced by a magnetic field - Iron, cobalt, Nickel
High Permeability - A material that will easily accept magnetic flux
The elements iron, nickle and cobalt are natural magnetic materials "they each have two valence electrons spinning in the same direction"
The armature is the moving part of a motor
Commutator acts as a "switch" in a DC or universal motor to keep the magnetic fields of the armature and commutator chasing each other
Generator cores are typically laminated to reduce eddy current losses
Causes losses in Generators :
In a serries motor, all of the current flows through both the armature windings and the field windings.
The shunt motor uses parallel wiring
Period - time required for an AC signal to complete one full cycle
The period of an AC waveform is measured in "seconds"
Frequency - # of cycles per second
The effective value - The value of an AC sine wave that exactly produces the same amount of heat in a load as a DC signal
Triangle wave, square wave, sine wave
V peak = Vrms * .707
The voltage rating stamped on a capacitor should not to be exceeded
two parts of any capacitor are dielectric and metal plates
symbol for capacitance is C, and is Measured in (F)arad
Capacitors store their electrical charges as:
Electrolytic capacitors differ from most other types of capacitors in that they are "polarized (have +/-)"
Since connecting capacitors in series increases the effective thickness of their dielectrics, this decreases their total capacitance because it effectively increases the distance between the plates
Parallel Capacitors CT = C1 + C2 + C3 + ...
Time Constant t = RC
Inductance is caused by energy stored in an electromagnetic field