electronics & communication: 2008

Friday, January 18, 2008

AMATUER RADIO

Don't miss our Amateur Radio Page - CLICK HERE

While you can get by with a make-shift workbench made out of anything handy like a few boxes or boards but a real workbench is a delight. Some use a door laid flat across some saw horses as a start. Building a real sturdy workbench out of two by four lumber is better.

A nice long electrical outlet strip is also most a must. You can see what I mean in the picture at the left. The outlet strip is just below the row of colored plastic bins. A shelf on your workbench to hold your test equipment is also nice. Also, notice the light above the workbench - also a must. You can also add swinging lamps as well. If you can afford it you can purchase a nice workbench like in the picture already built. A good sturdy stool or chair is a must as well.

Lots of additional shelving and storage boxes will help you sort out parts you may have and keep the labeled for easy location when you need them.

Try to keep your workbench free after you complete a job or project. Otherwise you will end up with no bench top space left to start new projects. That is why additional shelf and storage is a must. If you follow these rules you will have a nice looking as well as an efficient place to work. Electrostatic protection of delicate high speed IC's should be considered also when constructing your work space. Carpet on the floor is a no-no because of static electricity it can generate.

Also add a waste basket and a metal storage bin or cabinet of some sort to store chemicals. You will collect control cleaner, glues and various other chemicals that need proper and safe storage

A separate workbench could be added for drilling and other metal working. A nice vise, grinding wheels, and drill press are necessary at times for building metal enclosure boxes. Enjoy your new workbench and work space

SHOP PRACTICES

Step one is to have the proper soldering iron, solder and technique. The soldering iron's tip size and wattage should match the size of the job. If you are working on printed circuit boards a 25 watt pencil sized iron is appropriate with tips 1/8th inch or smaller. Cordless irons work well here and may be less likely to induce unwanted voltages. Bench-top thermostatically controlled irons can be ideal for most work. The temperature of the iron should be adjusted just high enough to heat the part being solder to just above the melting point of the solder. This is usually around 360 degrees F. The tip temperature will need to be somewhere around 460 to heat the part sufficiently and melt the solder. You must also consider the problems of static discharges with any iron if you are working on circuits with installed sensitive integrated circuits or field effect transistors. You may also need to use a heat sink to protect installed parts from excessive heat. Alligator clips or heat sink clamps will help. The main purpose of the iron is to heat the part being soldered to just high enough temperature to melt the solder. The solder (60/40 tin/lead of .025 to .040 inches in diameter) is place on the part being soldered not the iron. Although briefly touching the solder to the iron tip prior to the actual soldering can be helpful in transferring the irons heat to the part. Avoid touching the solder to the iron when soldering; touch the solder to the part. This is insurance against a cold solder joint which is to be avoided. A cold solder joint is one where the part was not hot enough to melt the solder and results in a poor connection. Normally the use of a rosin core solder is sufficient for most soldering jobs. Occasionally for larger work adding a separate soldering rosin paste may facilitate a better job. For larger work a handheld soldering gun is appropriate. Even larger work such as copper water pipes will require the use of a propane torch. For copper water pipes be sure the solder contains no lead. The larger the job the larger diameter solders are appropriate. Regardless of the size of the project the basic principles are the same. The finished soldering job should be smooth and shiny, not dull. On new printed circuit boards it is often helpful to apply a tin coating to the copper runs to insure all the connections are of low resistance and avoid later problems due to corrosion. Click>> for BASIC SOLDERING GUIDE.
SOLDERING

ANTENNA WAVELENGTH CALCULATOR

Enter operating frequency and then click the full wavelength (WL) or 1/2 or 1/4 wavelenth button. to see antenna length required.

MHz
= ft. (or inches.)

Free JavaScripts provided
by The JavaScript Source

--------------------------------------------------------------------------------

TELEVISION VIDEO

Television means "seeing at a distance". It may be described as a system for the conversion of light rays from still or moving scenes and pictures into electric signals for transmission or storage, and subsequent reconversion into visual images on a screen.

Basically the image formed by the camera lens is focused on a light sensitive material that is scanned in horizontal lines with each line following closely beneath it. The light intensity (and color) is converted into an electrical signal and transmitted over the air or through cables to a receiver. The "TV" receiver converts the electrical signals back into scan lines traced on a cathode ray tube (CRT). The fluorescent material on the face of the CRT is activated by the CRT's scanning electron beam to re-form the picture.

Basic Video information HERE. http://webs.soltec.net/movpic/Video.htm
NTSC signal information: http://www.seanet.com/Users/bradford/ntscvideo.html
Free television and video articles and guides HERE. http://www.videouniversity.com/article2.htm

Understanding & Measuring Video TV-RF Signals http://www.sencore.com/newsletter/Mar02/TVRFpartIII.htm

Click HERE to view a "large list" of links related to television and video.

Electronics Tutorials - Williamson Labs!

Electronics Design
Tutorials on electronics
Basic electronics
Electrical engineering

--------------------------------------------------------------------------------

Unijunction Transistor Tutorial
Biploar Transistor Tutorial
Animated Photonic Transistor Tutorial
Learning to use Transistors and LEDs
The 555 Timer Kit - Oscillators and Pulses
transistors
Helpme for 'UC Berkeley Spice 3f5'
MotionNET.com - Semiconductors - Discretes: Transistors ...
NPN Tutorial
Graphing
No matter what program you have to help you, everyone needs to understand why we produce graphs, and how to interpret them properly. Here's a basic guide, including paper to print out!
Log Graphs - essential for A-level candidates!
FREE Graph Paper! - all popular metric sizes!

--------------------------------------------------------------------------------

COMOS DATASHEETS
http://www.electronics-lab.com/downloads/datasheets/cmos.html

TTL DATASHEETS
http://www.electronics-lab.com/downloads/datasheets/ttl.html

More at http://www.electronics-lab.com/downloads/index.html

--------------------------------------------------------------------------------

NEWS! Click on titles below for the latest breaking news - updated every 15 minutes.

"AT&T Corporation" NEWS.
"Computer Security" NEWS.
"Computer Services" NEWS.
"Consumer Electronics" NEWS.
"Digital Television" NEWS.
"Engineering" NEWS.
"Handhelds" NEWS.
"Hewlett Packard" NEWS.
"IP and Patents" NEWS
"Microsoft" NEWS
"PC Industry" NEWS
"PC Software" NEWS
"Personal Technology" NEWS

TELEVISION TUTORIALS

Williamson Labs!

Television Tutorials 1_ NTSC: Introduction
2_ Scanning, Timing/Sync, Sync Recovery, Numbers
3_ Gain & Offset, D.C. Restoration, Gamma Correction
4_ Resolution, Bandwidth, Spectrum
5_ Color Physics: Eye, CIE
6_ Color Encoding: Color Bars, Camera,
RGB, YIQ, Color Subcarrier
7_ Color Decoding:
8_ Digital TV/Graphics: ADC-DAC, Frame Buffers, Timebase Correction, VGA
9_ VCR: Spectrum, Circuits
10_ Circuits & Practices: D.C. Restore, Proc Amps, DAs

EIA 1956 Video Resolution Chart for printing

http://www.bealecorner.com/trv900/respat/EIA1956.pdf

BASIC DIGITAL ELECTRONICS

Digital electronics is based on electronic switches. A circuit is either on or off represented by the presence of a voltage or not or in some cases two different voltages. A string of on or off conditions are made to represent numbers. These are usually binary numbers but could be based on a variety of mathematical bases. For example, "Hexadecimal" or a base of 16. But the most common is binary. Any number can be represented in a binary based system with a series of ones' and zero's (voltage on/off conditions). Here is a short table of some binary numbers and their decimal equivalents. The binary numbers place values from right to left as shown in the table are; one, two, four, and eight. So, binary 1111 is the same as adding 1+2+4+8 from right to left and that equals 15. See the samples below then study the chart.
1 1 1 1 = 15 binary 1 0 0 1 = 9 binary 1 0 1 1 = 11 binary
8+4+2+1 = 15 decimal 8+0+0+1 = 9 decimal 8+0+2+1 = 11 decimal
DECIMAL=
BINARY
DECIMAL =
BINARY
0
0000
8
1000
1
0001
9
1001
2
0010
10
1010
3
0011
11
1011
4
0100
12
1100
5
0101
13
1101
6
0110
14
1110
7
0111
15
1111
For an online course on digital electronics and how binary mathematics is used in LOGIC blocks visit this web site: http://www.gamezero.com/team-0/articles/math_magic/micro/comb.html
Digital Projects: http://www.eleinmec.com/category.asp?3
These basic concepts are the building blocks for more sophisticated configurations of digital electronic integrated circuits. Today digital integrated circuits combine hundreds and thousands of switches per IC package. It is not necessary to know exactly what the internal circuitry is but you must know the fundamentals to understand how to use the IC's together to build digital equipment. Our computer industry today depends upon many people knowing and using these same basic fundamentals.
Digital Electronics Online Problem - http://science-ebooks.com/electronics/digital_electronics.htm
Digital Electronics & Superconductors http://www.ece.rochester.edu/~sde/cool/coollinks.html
Howstuffworks "How Electronic Gates Work"
Digital Electronics Corporation
Digital Electronics II
Digital Logic
TTL Logic
Digital Logic and Computer Systems College Course http://www.physics.mcmaster.ca/phy4d6/ McMaster University, Hamilton, Ontario, Canada.
Digital electronics Book recommendation: Digital Systems, by by Ronald J. Tocci (Author), Neal S. Widmer (Author)

EXCELLENT!
Reviewer: A readerI use this book for a digital course im taking. Its GREAT at conveying information in a manner that you can understand. It starts of SIMPLE (things like number systems), and takes you to the basics of circuits (AND, OR, NOR, NAND, NOR, gates), and then takes you into some very detailed things. By the time your done with this you will be able to design your OWN circuits and impress your friends :-)

CHAPTER3: REACTANCE AND IMPEDANCE -- INDUCTIVE
AC resistor circuits
AC inductor circuits
Series resistor-inductor circuits
Parallel resistor-inductor circuits
Inductor quirks
More on the ``skin effect''
Contributors
CHAPTER4: REACTANCE AND IMPEDANCE -- CAPACITIVE
AC resistor circuits
AC capacitor circuits
Series resistor-capacitor circuits
Parallel resistor-capacitor circuits
Capacitor quirks
Contributors

Chapter 3: REACTANCE AND IMPEDANCE -- INDUCTIVE
AC resistor circuits
AC inductor circuits
Series resistor-inductor circuits
Parallel resistor-inductor circuits
Inductor quirks
More on the ``skin effect''
Contributors
Chapter 4: REACTANCE AND IMPEDANCE -- CAPACITIVE
AC resistor circuits
AC capacitor circuits
Series resistor-capacitor circuits
Parallel resistor-capacitor circuits
Capacitor quirks
Contributors

CHAPTER 2: COMPLEX NUMBERS
Introduction
Vectors and AC waveforms
Simple vector addition
Complex vector addition
Polar and rectangular notation
Complex number arithmetic
More on AC ``polarity''
Some examples with AC circuits
Contributors

VOLUME2-AC

Chapter 1: BASIC AC THEORY
What is alternating current (AC)?
AC waveforms
Measurements of AC magnitude
Simple AC circuit calculations
AC phase
Principles of radio
Contributors

Chapter 3: ELECTRICAL SAFETY
The importance of electrical safety
Physiological effects of electricity
Shock current path
Ohm's Law (again!)
Safe practices
Emergency response
Common sources of hazard
Safe circuit design
Safe meter usage
Electric shock data
Contributors
Chapter 4: SCIENTIFIC NOTATION AND METRIC PREFIXES
Scientific notation
Arithmetic with scientific notation
Metric notation
Metric prefix conversions
Hand calculator use
Scientific notation in SPICE
Contributors

Chapter 2: OHM's LAW
How voltage, current, and resistance relate
An analogy for Ohm's Law
Power in electric circuits
Calculating electric power
Resistors
Nonlinear conduction
Circuit wiring
Polarity of voltage drops
Computer simulation of electric circuits
Contributors

ALL ABOUT CIRCUITS

VOLUME1-DC
Chapter 1: BASIC CONCEPTS OF ELECTRICITY
Static electricity
Conductors, insulators, and electron flow
Electric circuits
Voltage and current
Resistance
Voltage and current in a practical circuit
Conventional versus electron flow
Contributors

CALCULUS

Scared of calculus symbols? No need to be as they are not meant to scare you. They are really very simple once you know how to think about them and know what they represent. For example, often you will see the symbol d or perhaps dx in a formula. Well, d simply means a small amount of something. So, dx simply means a small amount of whatever x represents. Don't try to multiply the two (d and x), they are not meant for that, just think of dx as a small amount of x, period. The symbol dx is called a differential. Also, you might have seen this symbol, called an integral. Now that is scary, right? No, not any more because I know it is simply a tall skinny S. Now how can a tall skinny S scare anyone? If you think of as meaning "the sum of" (the word sum starts with an S) well, that isn't scary either. I know that 4 is the sum of 2 + 2 already. Let's say you wanted to add up all the little bits of x and determine the sum of all the dx's you have. Now putting these two symbols together,dx simply represents "the sum of", all the "little bits of x" that you have. This process is often called integration. Integral calculus involves adding up little bits of things. A better definition might be, "the part of calculus that deals with integration and its application in the solution of differential equations and in determining areas or volumes etc." For more information and explanation of the definitions of integral and differential calculus see this page - HERE - and more HERE.
So how does calculus help us in electronics? The whole purpose of calculus is to make very difficult calculations easier. Yes, sometimes down right easy or usually at least somewhat easier. Most people think calculus is designed to make simple calculations difficult to impossible. But that is only because they really don't speak or understand calculus. It is sort of a foreign language. Learn to understand the language like we did above and calculus gets a lot easier. One example is calculating a transformer rate of change in output voltage at any one given instant. A much easier problem to solve if you use calculus. Who dreamed this calculus stuff up any way? If you want to read about the history of calculus go HERE. If you want another clear explanation of calculus read this - HERE.
See some examples of differential calculus and how it it used in electronics HERE.
Useful calculus links
Rules for limits
Derivative of a constant
Common derivatives
Derivatives of power functions of e
Trigonometric derivatives
Rules for derivatives
The antiderivative (Indefinite integral)
Common antiderivatives
Antiderivatives of power functions of e
Rules for antiderivatives
Definite integrals and the fundamental theorem of calculus
Differential equations
Calculus Reference
Calculus Resources - Comprehensive!!
Calculus Tutorial
Calculus Explained with Pictures
Calculus Aids - Reference - Solutions - Formulas
Calculus Without Tears
GREAT CALCULUS Java Applets for Learning
Understanding CapacitanceInductance Formulas - Science Forums and Debate
A function is something whereby you can put in some variable and get a different, dependant variable out. So, if f(x)=2x-3, you can put in some value, say 6, and get f(6)=2(6)-3=9.Differentiation of a function is the generation of another function for which the "y-value" (value of the dependant variable at a given "x-value," or independant variable) of the second is equal to the gradient, or slope, of the first.For example, take the function y=f(x)=x^2. For any given x, there is a y that is equal to x^2. The derivative of this function happens to be f1(x)=2x, meaning that for a given point on the original curve, its slope can be represented by 2x. So, at x=4, f(x)=4^2=16, and its slope at that point, f1(x)=2(4)=8, or 8 units up for every 1 unit over.The dy/dx means instantaneous change in y divided by instantaneous change in x. An explanation: Slope is measured by change in y divided by change in x. So between two points on a curve, the y-value of the second minus the y -value of the first, all divided by the x-value of the second divided by the x-value of the first, will give you the slope of the straight line between those two points, also called the secant. But we want the slope at a point, which poses some problems. How can there be any change at one point? Well, there can't, really, but what we can do is find the change between two points which are closer to one another than any finite distance. We can determine through algebra that as you make the distance between them smaller and smaller, the change in y over change in x gets closer and closer to some definite ratio, which is the "limit" as the distance between them "approaches zero." Thus, the "dy/dx" is that ratio at an infinitely small distance, thereby effectively being the slope at one point.Understanding CapacitanceInductance Formulas - Science Forums and Debate
If it's an upper case sigma then that means the sum of a sequence.
It's got everything to do with integrals. An integral is the sum of the rectangles under the curve, change in x (width) times height, the change in width approaches zero and the number of rectangles approaches infinity. Sums are where integrals come from. It's basically "the sum of all y-values."Understanding CapacitanceInductance Formulas - Science Forums and Debate
For AC electronics, designing circuits is easily done, using complex numbers.Imagine a voltage source with a angular frequency ω and amplitude A, so as function of time you have V(t) = A*cos(ωt).Now, replace this with a voltage X(t) = A*exp(ωt). Now, the real voltage can be written as the real part of X(t), being Re(X(t)) = A*cos(ωt).Using this formalism, you can treat every passive linear component as a complex resistor Z. For lumped devices there are basically three types:Capacitor with capacity C: Z = 1/jωCResistor with resistance R: Z = RInductor with inductance L: Z = jωLHere the number j has the property j² = -1.Now I'll give an example with three nodes, GND, VIN, VOUT. Between GND and VIN there is a voltage source X(t). Between VIN and VOUT there is a resistor R. Between VOUT and GND is a capacitor C. What is the output voltage as function of input voltage?This now can be easily solved. We introduce a complex voltage XOUT and XIN.We have a series connection of two resistors. Using basic circuitry for resistors you findXOUT = XIN * (ZC / (ZC + ZR)), where ZC is the capacitor's complex resistance and ZR is the resistor's complex resistance.Now XOUT = XIN *(1/jωC) / (R + (1/jωC)) = XIN / (1 + jωRC)So, you have XOUT as function of XIN and the angular frequency ω.The amplification as function of frequency ω can be written as 1/sqrt(1+ω²R²C²). There also is a phase shift, between input and output. That is -arg(1 + jωRC). For small ω (close to DC), the phase shift is close to 0, for high ω, the phase shift is almost 90 degrees.If you understand complex numbers, then this should be easy to grasp, otherwise it indeed will be very difficult for you to determine transfer functions of capactive and inductive circuits.The key to understanding these things is"transfer function""complex arithmetic""bode plot""poles and zeros""laplace transform"http://en.wikipedia.org/wiki/Transfer_function
__________________
Understanding CapacitanceInductance Formulas - Science Forums and Debate

Volume Functions A Maximization Problem
Calc 101 Automatic Calculus Solutions
AP Physics & Calculus Problems of the Week From Kentridge High School
Interactive Calculus - Teachers can write Ron Larson odx@psu.edu for a free subscription.
AP Calculus from the College Board
Physics and Calculus Problems of the Week
Finite Mathematics and Applied Calculus Resource Page
Alvirne HS Problem of the Week A gold mine of current and archived problems
Visual Calculus
Dave Slomer's Calcu Page
The Rental Car Problem from CCP
Mr. Calculus
The rise of calculus For the history buffs among us
www.calculus.net
AP Calculus on the Web from Sandy Ray
First Semester Calculus The Continuity-Differentiability Issue
The Calculus Hater's Homepage The other side heard from (poor fellow)
Karl's Calculus Tutor Lots of information
AP Distance-Learning Project
Dr. Papa's Course at Rice U. complete with exams
Integral Calc Exam from U of Pitt
Differentiation Problems from U of Pitt
Integration Problems Same Place
CalculusQuest
Learning Calculus A How-To-Be-Successful List of Tips
The MATHMAN Something about teaching Calculus to 7 year olds
Dr. Sloane's Calculus 1 and 2
I Love Calculus
Need to understand electronics, with or without the math? Everyone needs this book. The title is a little misleading but believe me you don't want to be without this clearly written, hands on, basic electronics book.

MATH FOR ELECTRONICS

Do you need math skills to understand electronics? Yes! All sciences including electronics (a division of physics) requires a certain understanding of mathematics. If you are interested in electronics only as a hobby then general math may be all you will need, to get by. If you are serious about becoming an electronic technician then you will need at least a basic understanding of algebra and and be able to use and make graphs. Electrical engineers need advanced mathematics training through calculus.
Why, you may ask? Basic electronics involves the use of equations. For example, Ohms law requires a basic knowledge of algebra to fully understand it and to be able to use it effectively. Electronic technicians will use Ohms law and other algebraic formulas frequently in typical day's work. Some knowledge of trigonometry would be helpful. Electrical engineers need to know how to calculate various rates of change in electrical parameters in a quick and relatively simple manner. Without the appropriate skills at your level of interest you will be greatly handicapped in your work. There are substitutes for many situations such as pre-printed charts, databases, cookbook circuits, and internet resources. But they may not quite serve your current purpose and will take time to research and find. It is best to obtain basic math skills to a level required by your specific work.
Learn algebra here.
Learn about graphs here.
Learn about graphs of a line here.Learn about graphing a function here.
Learn more about domain and range here.
Learn about geometry HERE.
Learn about statistics for electronics HERE
Learn about trigonometry here.
Learn calculus here. (Don't miss this - click)
Learn about using MathCad for electronics problems.
See our mathematics section for more math links.

RESONANT CIRCUITS

Resonance[PDF] Sophomore Physics Laboratory Analog Electronics: Resonant Circuits[PDF] ELEC290: Linear Circuits (Electronics II)Electronics 38 RESONANT CIRCUITS AS FILTER CIRCUITS CASPOC - Power Electronics Simulation Software Resonance in series-parallel circuits - Chapter 6: RESONANCE Electronics Technician - Program Outline Electronics - T Interactive Power Electronics Seminar (iPES)
Also see, ALL ABOUT CIRCUITS: http://www.allaboutcircuits.com/vol_2/chpt_9/1.html
Electrical Circuit Theorems - EngPlanet.com: Library of Electrical Circuit Theorems http://www.engplanet.com/redirect.html?1900
Resonant Circuits:
Parallel Resonant Circuits Resonant Circuits I Resonant Circuits II resonance RESONANT CIRCUITS III RESONANT CIRCUITS AS FILTER CIRCUITS[PDF] Resonant Circuits by Time and Frequency[PDF] Sophomore Physics Laboratory Analog Electronics: Resonant Circuits Resonant Circuits in a Magnetron Tube A Composite Capacitor/Inductor Assembly for Resonant Circuits
SOFTWARE
CaMF1.zip
51k
LP or HP filter and matching circuit calculation. See notes on CaMF
CaLC3.zip
46k
General impedance calculations, LC circuits calculations. Textfile describes, how to use it.
CaNI1.zip
41k
RX front-end IMD and noise figure calculations
CaIT1.zip
48k
Toroidal coil calculations
CaIW1.zip
45k
Wire coil calculations
CaQI1.zip
39k
Inductance and Q measurement helper program
Ca2LQ1.zip
42k
Inductance and Q measurement for coils with parasitic capacitance
CaXtal1.zip
44k
Quarz crystal calculator. It calculates equivalent circuit values from a measurement in a 50 ohm line
CaRA1.zip
44k
Resistive attenuator calculations
Xline1.zip
49k
Microstrip stub design, general tapered stub with reactive termination
Tline2.zip
54k
Impedance transform in a transmission line with microstrip calculations
Ferrite (software program) is used to calculate the number of turns required on toroidal ferrite cores to achieve the desired millihenry-value inductance. 15 different ferrite toroids are included in this application. This program will calculate the winding data for an inductance range of 0.001 to 27 millihenries.Style: CONSOLE , File size: 64K , zipped 31K.Bug Fixes: Thanks to PA3CKR for the bug report ; fixed Jan 19/99.Current Version is 1/19/99Download the ferrite.zip file
Summary of Basic Electronics Fundamentals
Ohm's Law
Resistance
Capacitance
Inductance
Reactance
Resonance
Q of a Circuit
Tuned Circuit
Transformers
Audio
Freq. vs. Wavelength
Antennas

A WONDERFUL PHYSICS SITE: Hyper Physics http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

TOROIDS-FERRITE CORES

Today you must learn about powdered iron cores and ferrite materials for winding your own toroidal coils. Click here for basic background information on powdered iron and ferrite materials. You will need to know the formulas for calculating toroidal core inductors; click HERE for FORMULAS. The cores will be made from different materials. You will also need information on powdered iron material. Now you have all the information you need to wind toroidal coils for your electronics projects. For core material table: http://www.hills2.u-net.com/electron/induct.htm#Ferrites For core material for RF applications: http://www.amidoncorp.com/ace_iptcforrf.htm
To calculate the approximate inductance of a toroid, use the JAVA calculator found here: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indtor.html#c1 Courtesy of Carl R. (Rod) Nave, Georgia State University. Be sure to visit their main site loaded with JAVA calculators and other science information at: HyperPhysics http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html including an offer of a CD containing of all their fine materials.
Toroid Approximate Inductance CALCULATOR - Toroid CALCULATOR
Introduction - Use of Ferromagnetic Cores
Choice of core material - choice of material is of prime importance
What size toroid core? - Design examples are given
Using the data tables
Winding hints
Line filters and chokes
Switched mode supplies
Variable coil forms
Suppression beads
Bobbin core
Balun cores
Core cross references
Downloads
RFI suggestions
Magnetic formula
Australian resellers
Price lists
Ordering information
Links
Torroid Inductance charts: http://www.electronics-tutorials.com/basics/toroidcharts_mcq.htm
http://home.sandiego.edu/~ekim/otherjunk/inductor.pdf
Impedance/Reactance http://www.kpsec.freeuk.com/imped.htm
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 deg.C 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.
Useful hints concerning winding toroid coils.
Building a toroid http://www.hamradio-online.com/1999/apr/w6bky-10.html
Toroid Inductance Charts http://www.electronics-tutorials.com/basics/toroidcharts_mcq.htm
A GREAT Inductor Impedance CALCULATOR online - http://www.cvs1.uklinux.net/cgi-bin/calculators/ind_imp.cgi
A GREAT Tuned Circuit Impedance CALCULATOR online - http://www.cvs1.uklinux.net/cgi-bin/calculators/tuned_circuit.cgi

INDUCTORS

Inductors are usually made with coils of wire. The wire coils are wound around iron cores, ferrite cores, or other materials except in the case of an air core inductor where there is no core other than air. The inductor stores electrical charge in magnetic fields. When the magnetic field collapses it induces an electrical charge back into the wire. Inductors are associated with circuit capacitance and can form a tuned circuit and resonate at a particular frequency. Two coils close to one another, as they are in a transformer, literally transfer charge from one coil to the other. This is called mutual inductance.
Inductor Calculators:
Inductor Calculator SMIrC Laboratory - Spiral Inductor Calculator Shavano Music Online - Cross-Over Network; Air Core Inductor Jim Hawkins' Java Radio Calculators Inductor Calculator RF Cafe - Inductor Calculator Spreadsheet DC Choke Design Calculator The educational encyclopedia, datasheets Circuit Sage: Inductor Tools and Links The Engineers' Club Online Service - Engineering Calculators

Capacitor Information (GOOD!) http://www.interq.or.jp/japan/se-inoue/e_capa.htm
Capacitance Value Calculator: http://www.fis.unb.br/Fis3Exp/fcim.csdc.com/fcimis/compid/caps/cap6.html
Capacitor Codes: EngPlanet: http://www.engplanet.com/redirect.html?3804
How To Read Capacitor Codes http://xtronics.com/kits/ccode.htm
Another capacitor code link: http://www.alfalima.net/condensator.htm
A GREAT Capacitor Impedance CALCULATOR online - http://www.cvs1.uklinux.net/cgi-bin/calculators/cap_imp.cgi
A GREAT RC Time Constant CALCULATOR online - http://www.cvs1.uklinux.net/cgi-bin/calculators/time_const.cgi
Visit the electronic calculator home page - http://www.cvs1.uklinux.net/calculators/index.html
Calculating capacitor combined value when in series or parallel:
Page 217 is a Very nice calculator Parallel and Series Capacitors Series and Parallel Capacitors Series and Parallel Circuits Series / Parallel Capacitor Calculator Series and parallel capacitors - Chapter 13: CAPACITORS - Volume I Adding Capacitors in Series and Parallel (DC)[PDF] Capacitors in Series & Parallel Parallel: Series:Capacitors in Series Parallel-Plate Capacitors
Resistance, Frequency, Capacitance Calculator: http://www.opamplabs.com/rfc.htm
CAPACITOR CIRCUITS
AC capacitor circuits - Chapter 4: REACTANCE AND IMPEDANCE Parallel resistor-capacitor circuits - Chapter 4: REACTANCE AND Capacitor Circuits ilar pages Discover Circuits - Super Capacitor Circuits Incomplete capacitor circuits www.sweethaven.com/acee/forms/frm0903.htm www.sweethaven.com/acee/forms/frm0902.htm[PDF] Application Brief 109 - Switched Capacitor Circuits Provide [PDF] ∫ ∫ ∫Lab 206 Capacitor Circuits

capacitor

A capacitor is a device that stores an electrical charge when a potential difference (voltage) exists between two conductors which are usually two plates separated by a dielectric material (an insulating material like air, paper, or special chemicals). Capacitors block DC voltages and pass AC voltages. They are used as filters, AC coupling capacitors and as by-pass capacitors. They are also used in conjunction with resistors and inductors to form tuned circuits and timing circuits. A capacitors value C (in Farads) is dependent upon the ratio of the charge Q (in Coulombs) divided by the V (in volts). Common capacitors come in values of microfarads or Pico farads. Often you will have to convert between Pico farads and micro farads. A chart is provided below to assist in the conversion. For a list of capacitor terms defined: Click HERE. Measuring capacitance requires a capacitance meter. This is separate piece of test equipment. There are attachments for multimeters that allow measurement of capacitance directly. Also read this tutorial on how to test capacitors.
CAPACITOR Value Conversions:
Some capacitors may be marked in micro farads and others of the same capacitance value marked in Pico farads. One Pico farad equals one micro-micro farad. You may need to make conversions between the two equivalents.
Prefix
Power of 10
Example
Mili
10-3
.001
Micro
10-6
.000001
Nano
10-9
.000000001
Pico
10-12
.000000000001
Micro F = Pico FPico = uuf so; .01uf = 10000 pf .001uf = 1000 pf .005uf = 5000 pf .009uf = 9000 pf .0001uf = 100 pf .0005uf = 500 pf .0009uf = 900 pf

A capacitor marked 104M is a .001 uf +- 20% A capacitor marked 103M is a .01 uf +- 20% A capacitor marked 102M is a .1 uf +- 20%

Electronic Analog circuits

Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.
Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuit is usually called "mixed signal."
Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.

[edit] Digital circuits
Main article: Digital circuits
Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low" and "High". Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.
Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digital circuits. Digital Signal Processors are another example.
Building-blocks:
Logic gates
Adders
Binary Multipliers
Flip-Flops
Counters
Registers
Multiplexers
Schmitt triggers
Highly integrated devices:
Microprocessors
Microcontrollers
Application-specific integrated circuit(ASIC)
Digital signal processor (DSP)
Field-programmable gate array (FPGA)

[edit] Mixed-signal circuits
Main article: Mixed-signal integrated circuit
Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits and digital circuits combined on a single semiconductor die or on the same circuit board. Mixed-signal circuits are becoming increasingly common. Mixed circuits are usually used to control an analog device using digital logic, for example the speed of a motor. Analog to digital converters and digital to analog converters are the primary examples. Other examples are transmission gates

electronics & communication