Basic Electronics Cliffnotes
Written by Edvin Eshagh   

Basic Electronics

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"
The zinc assumes a strongly "negative" charge"
 When the copper is placed in a solution it becomes very "weakly" charged with a "negative" charge.  The copper acts as if it is "positive" with respect to the zinc.
, if a wire is connected between the zinc and the copper a current of electrons will flow from the "zinc" to "copper"

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
"force" between charges using "tosion balance"

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


The smallest piece of a compound is a 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 -
free electrons are free to move around between atoms

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:
1) chemical reactions
2) rubbing things together
3) radiant energy such as sunlight
4) Influence of magnetism on conductors

10^12 Tera
10^9  giga
10^6  mega
10^3  Kilo
10^2  Hecto
10^1  deca
10^-1 deci
10^-3 mil
10^-6 micro
10^-9 nano
10^-12 pico

Columb = The electrical charge carried by 6.24 x 10^18 electrons

I = Current
Q = Charge in Columbs
I = Q/T

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 :
hysteresis losses occur when magnetic material resist being magnetized.  It results in heat being developed in the magnetic materials.
copper losses are caused by the resistance of the copper wires in the motor coils and connection leads.
eddy current are circulating currents in the iron of the electromagnetic cores used in motors.

In a serries motor, all of the current flows through both the armature windings and the field windings.
as the current increases, the magnetic field increases in both field magnets and the armature. This makes series motors have high torque, but they can also "run away" and spin so fast that they self destruct

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:
1) extra electrons on the negative plate
2) a deficiency of electrons on the positive plate
3) an electrostatic field in the insulator caused by the opposite charges on the plate

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 + ...
Serries Capacitors CT = (C1 * C2) / (C1 + C2)

Time Constant t = RC

 Inductance is caused by energy stored in an electromagnetic field

As a current in a inductor increases, a magnetic field also increases, which induces a counter electromotive force (CEMF).

Unit of inductance is in Henries, and its symbol is H
The symbol for inductance is L

Inductance is the characteristic of an electrical conductor that opposes a change in current flow

An inductor is a device that stores energy in a magnetic field

Resistor-Inductor circuit Time Constant formula: T = L / R
It is the time required to increase 63% or to decrease 36%


Inductors in Serries:  Lt = L1 + L2 + L3 + ..... + Ln
Inductors in Parallel: Lt = 1 / ( 1/L1 + 1/L2 + ... + Ln )

transformers transfer "AC electrical power" from from the primary coil to secondary coil of the transformer. They may also change the voltage and current. If they raise the voltage they lower the current, or If they raise the current they lower the voltage

A transformer is made up of two coils and a Core

The primary and secondary coils of a transformers are not electrically connected to provide "electrical isolation" between two different circuits

voltage is increased from the primary of a transformer to the secondary, the current must "decrease"

"Autotransformer" has only one coil that acts as both the primary and secondary. It is tapped at different locations on the coil to give different voltages

Eddy current losses are found in a transformer's core

The input coil of a transformer is called the "primary"
and the output coil is called the "secondary" coil

A step-down transformer increases the "current" in the secondary

The turns ratio of a transformer lists the "number of turns of wire"

"Silicon" element has the symbol Si and atomic number 14.  It is semiconductor with 4 electrons in the valence (outer) shell. It is the second most abundant element in the Earth's crust, making up 25.7% of it by weight. It occurs in clay, feldspar, granite, quartz and sand, mainly in the form of silicon dioxide (also known as silica) and silicates (compounds containing silicon, oxygen and metals).

Germanium chemical element in the periodic table has the symbol Ge and atomic number 32. It is a lustrous, hard, silver-white, metalloid that is chemically similar to tin. Germanium forms a large number of organometallic compounds and is an important semiconductor material used in transistors.

The most energetic electrons are found in the highest orbitals of an atom

Covalent bonding is the sharing of electrons between atoms in a crytal formation

Semiconductor materials have electron energy band characteristics between conductors and insulators

Intristic Semiconductor is the pure semiconductive material that has not been doped

Doping is the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor in order to change the electrical properties of a semiconductor.

Pentavalent material is a material with 5 valence electrons; like arsenic and antimony

Carbon semiconductor material forms crystals known as diamonds

Trivalent doping material is an element with 3 valence electrons; like indium, gallium

N-type material - has electrons as majority
P-type material - has holes as majority carriers

Bipolar transistor - When a third layer is added to a semiconductor diode to form two separate P-type and N-type junctions. It can be best thought as a combination of a forward and a reverse biased diode.

Three parts or regions of a bipolar transistor are called:  emitter, base, and collector

PNP transistor - Type of transistor which contains two P-regions that are separated by an N-type material

NPN transistor - Type of transistor which contains two N-regions that are separated by a P-type material

The symbol for the emitter part of a NPN transistor is an outward pointing arrow.
For an NPN transistor symbol, the arrow symbol designates the emitter, points opposite to electron flow, points outward.

The correct biasing for an NPN transistor is negative on emitter, positive on base, positive on collector

A common integrated circuit amplifier is the "operational" amplifier

Charge (Q) measured in Coulombs (C)
Current (I) measured in Amperes (A)
Voltage (V or E) measured in Volts (V)
Resistance (R) measured in Ohms (Ω)
Power (P) measured in Watts (W)
Capacitance (C) measured in Farads (F)
Inductance (L) measure in Henries (H)

 

Electronics formula sheet