Electronic Engineering Students Help

Introduction

2010-12-15T01:14:00.002+05:00

Hello,
In this Blog, students of Electronic/Electrical/Computer Engineering will find the Topics & Materials which will be helpful to them.

Note that this blog will keep updating on regular basis, so please keep visiting for updates.
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Electronic Engineering blog .. electronic engineering articles, electronic engineering universities , technology , engineering ,electronic instruments tools. circuits ,basic circuits, projects

SSUET Section:

2010-02-22T20:14:00.025+05:00

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Engineering EBOOKS III

2010-01-22T14:24:00.009+05:00

Numerical Methods using MATLAB 3rd Ed NEW

Internetworking Technologies Handbook 4th ed

Data Communications and Networking by Behrouz A Forouzan 4th ed

Signal Processing & Linear System by B.P Lathi
Modern Digital & Analog Communications Systems-Third_Edition-B.P Lathi

Digital Signal Processing (Third Edition) by
John G. Proakis & Dimitris G. Manolakis.pdf

The CCNA Study Guide by Todd Lammle

Data And Computer Communications 5th - William_Stallings

The 8051 microcontroller and embedded systems by MAZIDI

Programming 16-bit PIC Microcontrollers in C Learning to fly the PIC 24 Embedded Technology

Microcontroller Projects in C - 8051

Serial Port Complete by Jan Axelson

Encyclopedia of Electronic 1000 Circuits

Embedded C Tutorial-8051

Electronic Projects in the Car-1979

Electronic Failure Analysis Handbook Techniques and Applications for Electronic and Electrical Packages, Components, and Assemblies

Electronic Devices and Circuit theory-Floyd- 7th Edition
In order to view this Ebook, you will have to download DJVU Reader. To dowload DJVU Reader, Click HERE

Digital Logic and Computer Design by Morris Mano 2nd Edt

Digital Fundamentals-Floyd- 9th Edition
In order to view this Ebook, you will have to download DJVU Reader. To dowload DJVU Reader, Click HERE

CRC Press Microcontroller Programming The Microchip PIC .Dec-2006

C & the 8051

Beginning Digital Electronics through Projects

Electronic Projects for Musicians - C. Anderson WW

Engineering EBOOKS II

2010-01-22T14:23:00.000+05:00

Signals and Systems, 2ed - A.V.Oppenheim & A.S.Willsky (Prentice Hall)

Electronics Projects For Dummies

Engineering Electromagnetics (6th Edition, 2001) - Hayt & Buck + Solution Manual

EXPLORING C FOR MICROCONTROLLERS

110 Electronic Alarm Projects 1984

110 IC Timer Projects 1985

1st Project 8051 C Using MikroC Assembler For 8051

Projects using OP-AMP IC

8051 Microcontroller Project - LED Blinking

8051 Microcontroller

8051 Microcontroller Architecture Programming & Applications

The 8051 Microcontroller Ebook : Ayala

An introduction to programming The Microchip PIC in CCS C

Analog & Digital Circuits for Electronic Control System Applications

Art of Assembly Language

Beginners Introduction to the Assembly Language of Atmel AVR Microprocessors

Encyclopedia of Electronic Circuits

Electronic Gadgets for the Evil Genius 21 Build it yourself Projects_Tab_Rob

Engineering EBOOKS I

2010-01-22T14:21:00.000+05:00

Probability_and_Statistics_for_Engineers_and_Scientists_8th_edition_by_Ronald_E._Walpole

The Art of Electronics by Horowitz Hill
Comprehensive book for learning Electronics from Beginning.

Teach Yourself Electric and Electronics 3rd edition by Malestrom

Schaum's Outlines--Theory And Problems Of Electric Circuit

How to program 8-bit microcontoller using c language

Interfacing with C++

Parallel Port Complete by Jan Axelson

USB port Complete by Jan Axelson

Design Criteria for Low Distortion in Feedback Opamp Circuits by Kluwer

Opamp circuits

30 projects using picbasic and pic basic pro by D.Ibrahim Newnes 2006

RLC Circuits & Basic Concept

Design With Operational Amplifiers And Analog Integrated Circuits by S.Franco

Schaum's Easy Outlines -- Differential Equations

Solary Energy Projects for the Evil Genius - 50 Projects

Make and Test Projects in Engineering Design by Springer
Creativity, Engagement and Learning

ELECTRONIC GADGETS FOR THE EVIL GENIUS--28 DIY PROJECTS

Capacitor Charge / Energy Calculator

2009-09-24T22:24:00.002+06:00

The calculator can find the charge (expressed in coulombs) and energy (expressed in joules) stored in a capacitor. Enter the voltage across the capacitor and the capacitance of it. The charge and energy will be shown on the right. The formulae used in the calculations can be found here in the technical data section.

Calculate Charge (Q) & Energy (J) from Voltage (V) & Capacitance (C):

Formulae:

Charge: Q = CV where C is the capacitance in Farads, V is the voltage across the capacitor in Volts and Q is the charge measured in coulombs (C).

Energy stored: W = ½ QV = ½ CV² where W is the energy measured in Joules.

Capacitance Unit Converter

2009-09-24T22:09:00.003+06:00

The calculator will convert between units commonly used for capacitance. Enter the value to convert, and the units to convert from and to. The converted value will be shown on the right.

Convert Between Units:

Calculators & Value Evaluators

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This section contains interactive calculators for resistor colour codes, ohms law, potential dividers and more, designed to simplify common calculations and teach basic electronic theory.

Be sure to bookmark EE Student Help and check back soon, as new pages are added frequently.

Note: All results are rounded to 3 decimal places. Multiplier suffixes such as M for meg, u for micro etc. are appended to the results and shown in the results boxes where appropriate.

Capacitance Unit Converter

Capacitor Charge / Energy Calculator

Capacitor Code Calculator

Inductor Code Calculator - Colours to Value

Inductor Code Calculator - Value to Colours

L / C Reactance Calculator

LED Series Resistor Calculator

Series/Parallel Array of LED's Current Limiting Resistor Calculator

Ohms Law Calculator

Potential Divider Calculator

Power (Wattage) Calculator

Series / Parallel Capacitor Calculator

Series / Parallel Resistor Calculator

Wheatstone Bridge Calculator

Resistor Colour Code Calculator

Weatstone Bridge

2009-09-21T12:55:00.000+06:00

The Wheatstone Bridge circuit consists of two potential dividers connected between the supply and ground. One divider is formed from R₁ and R₂, the other from R₃ and R₄. The voltage at the point between R₁ and R₂, and that between R₃ and R₄ will vary according to the resistor value. V_bridge is the voltage between these points, as shown in the diagram below:

When the voltages are equal V_bridge will be zero, at which point the bridge is said to be balanced. At this point the value of R₄ can be found from:

R₄ = (R₃ * R₂) / R₁

A typical application for a Wheatstone Bridge is for measuring resistance; if R₁ is variable and is adjusted it until V_bridge = 0 the value of R₄ can then be found from the above equation.
If all four resistor values (R₁ to R₄) and the supply voltage (V) are known the voltage across the bridge (V_bridge) can be found by working out the voltage from each potential divider and subtracting one from the other. The equation for this is:

V_bridge = (R₄ / (R₃ + R₄) * V) - (R₂ / (R₁ + R₂) * V)

This can be simplified to:

V_bridge = ((R₄ / (R₃ + R₄)) - (R₂ / (R₁ + R₂))) * V

If the bridge is balanced the equivalent resistance of the circuit between V and GND is:

R₁ + R₂ in parallel with R₃ + R₄
R_E = ((R₁ + R₂) * (R₃ + R₄)) / (R₁ + R₂ + R₃ + R₄)

WEEE / RoHS Directives

2009-09-21T12:53:00.000+06:00

2 new European directives are due to come over the next 2 years, both of which will have an impact on the electronics industry and hobbyists alike. Now is the time to understand the implications of these directives and prepare for them.

WEEE (Waste Electrical and Electronic Equipment):

The WEEE directive will make manufacturers responsible for disposal and recycling of products they produce. A few products will be exempt from WEEE, but manufacturers of those that are not must make provisions for products to be returned to them at the end of their life cycle. The manufacturers must then bear the cost of recycling these products. It is expected that legislation will be introduced by the end of 2004, with compliance by August 2005.

Manufacturers must think about how they will provide for this, as well as designing products to minimise the costs and environmental impact. Currently over 6 million tons of waste electronic equipment is dumped each year, WEEE aims to reduce this by encouraging environmentally sound design and shifting responsibility for recycling onto manufacturers.

RoHS (Restriction of certain Hazardous Substances):

This directive will probably have a bigger impact than WEEE on hobbyists. From 2006 the use of 6 substances commonly used in electronics will be restricted. These are lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers. In practice RoHS is linked to WEEE, as the environmental impact of these substances is greater than the health risks these pose.

RoHS will mean standard tin/lead solder can no longer be used, this in itself presents big problems. Firstly it is not just the solder you assemble boards with that is affected - components and PCBs must be lead-free too. Secondly lead-free solders have a higher melting point, increasing the risk of thermal damage to components and boards. RoHS could also affect the flux used in the solder too, again affecting the solder's properties. Thirdly there are a number of lead-free alternatives, often incompatible with one another, and as yet no set standard. If the solder you are using is not compatible with that used to tin component leads or the PCB you may run into problems. That said I have recently used lead-free PCBs with lead solder and experienced no problems.

See the May 2004 edition of EPE magazine for an excellent article on lead-free soldering and it's impact. If you plan to stock up on components or solder you should check whether they are lead free. Check this in catalogues and on manufacturers websites. Lead-free components should be kept separate from those containing lead. Businesses will need to keep documents from suppliers showing components are compliant in case a product's compliance is contested. More information about both directives can be found on the RS and Farnell websites, as well as Envirowise.

It must be remembered RoHS doesn't only affect solder, it will also affect other components that contain banned substances, such as Ni-Cad batteries. However in most cases alternatives are readily available. Controlled use of hazardous substances in some products will be permitted, most notably mercury in fluorescent tubes.

SI Units

2009-09-21T12:51:00.000+06:00

Quantity	Symbol	Units
Resistance	R	ohms (W)
Capacitance	C	Farads (F)
Conductance	G	Siemens (S)
Current	I	amperes (A)
Charge	Q	Coulombs (C)
Energy	W	joules (J)
Power	P	watts (W)
E.M.F	E	volts (V)
Mass	M	kilograms (Kg)
Length	L	metres (m)
Time	T	seconds (s)
Velocity	V	metres/second (m/s)
Angular Velocity	w	radians/second (r/s)

Series Combinations of R, C & L in A.C. Circuits

2009-09-21T12:50:00.003+06:00

R and L in series:

The voltages dropped across the inductor and the resistor must be added together using phasor summation, i.e. adding the two voltages as they would be shown on a phasor diagram, if the second phasor is drawn starting from the end of the first phasor. Since V_Lis at right angles to V_Rthen the components are added using pythagoras's theorem, a² = b² + c².

The triangle this makes shows the voltages V_R and V_L, and the total voltage V on the hypotenuse (see below).

Since V = IZ, dividing all the sides by I gives R, X_L and Z, the impedances.

Similarly, multiplying all sides by I gives I²R, I²X_Land I²Z , the power dissipated in the components.
The term impedance (Z) is used for the combination of component resistances and reactances, e.g. the 'circuit impedance' refers to the total impedance of a circuit containing a number of resistors, inductors and capacitors whose resistances and reactances have been combined using phasor summation.

Phase Angle:

The angle between the adjacent and the hypotenuse of the triangles is the phase angle of the combined components. I lags V.

f = cos^-1 (R/Z)

R and C in series:

As for R and L in series, except that for the phase angle of the two combined components, I leads V.

R, L and C in series:

This can be visualised from drawing all 3 components on a phasor diagram. The resistance is in phase, therefore it's phasor will be horizontal. The inductance will then have it's phasor going upwards, but the capacitance phasor will come down again from this point. The hypotenuse of the triangle is from the end of the capacitance phasor back to the start. This hypotenuse is the resultant voltage drop.

Again, the values can be divided and multiplied by I to give impedance and power respectively.

V² = (V_R² + (V_L - V_C)²)

Take the square root of these to get the voltage dropped, V.

RMS Values

2009-09-21T12:48:00.000+06:00

The Root Mean Square (R.M.S) value of a voltage or current is:

V_RMS = V_P / Ö2 and I_RMS = I_P / Ö2

where V_RMS and I_RMS are the R.M.S. values, and V_P and I_P are the peak values.

Ö2 » 1.414

Similarly, multiply R.M.S. by Ö2 to get the peak value.

Values quoted are R.M.S. unless otherwise stated - normally the R.M.S. subscript is left off.
E.g. 240V A.C. mains has a peak value of 240 X Ö2 = 340V peak.

R, C & L in A.C. Circuits

2009-09-21T12:47:00.000+06:00

Here are some general formulae for working out values in an A.C. circuit:

Resistors:

Resistors are exactly the same as in D.C. circuits

I = V / R P = I²R

Capacitors:

I = V / X_C

X_C is the capacitive reactance = 1 / (2pfC)
f is the frequency, C is the capacitance
(Remember Voltage lags Current by 90^o)

Inductors:

I = V / X_L

X_L is the inductive reactance = 2pfL
f is the frequency, L is the inductance
(Remember Voltage leads Current by 90^o)

Resistor Theory

2009-09-21T12:44:00.000+06:00

Resistors provide an obstruction to the flow of electricity around a circuit. A voltage is dropped across a resistor, dependant on the current flowing through the resistor. Here are some useful formulae:

Voltage Dropped across a Resistor:

V = IR, where I is in Amps, and R in Ohms

This can be re-arranged to give Current or Resistance if Voltage is already known (see ohms law).

Power Dissipated in a Resistor:

P = I²R or V²/R where P is in Watts

Always make sure the resistor's power rating is not exceeded!

Resistors in Series:

Putting resistors in series increases the total resistance:
R = R₁ + R₂ = R₃ .....
Note that the total resistance should be greater than that of any of the individual resistors.

Resistors in Parallel:

Putting resistors in parallel reduces the total resistance:
(1/R) = (1/R₁) + (1/R₂) + (1/R₃) .....
If you have only 2 resistors in parallel you can use:
R = (R₁ R₂) / (R₁ + R₂)
Note that the total resistance will be less than that of any of the individual resistors.

Preferred Resistor Values

2009-09-21T12:32:00.000+06:00

Resistors are available in a number of standard ranges, often called 'preferred values' These ranges, or series, are set out by the Electronic Industries Association (EIA), and are E3, E6, E12, E24, E48, E96 and E192. The number after the 'E' denotes the number of values the series contains per decade. The E3 and E6 series aren't really used these days; the most common series is probably E24. The series are logarithmic and are derived from the resistor tolerance; resistors with a tighter tolerance can have more values in the series that won't overlap one another. The series are sometimes referred to by the tolerance, the two being related as follows:

E3: 50% tolerance
E6: 20% tolerance
E12: 10% tolerance
E24: 5% tolerance
E48: 2% tolerance
E96: 1% tolerance
E192: less than 1% tolerance

When designing a circuit you need to round calculated resistor values to a preferred value. Normally this would be the value closest to the calculated one for the series you are using. However in some circumstances its better to round up to the next higher value, such as with current limiting resistors where using a value smaller than calculated could overload a component. The tables below show the values for some of the more common preferred series.

E12 Series:

1R0	10R	100R	1K0	10K	100K	1M0	10M
1R2	12R	120R	1K2	12K	120K	1M2
1R5	15R	150R	1K5	15K	150K	1M5
1R8	18R	180R	1K8	18K	180K	1M8
2R2	22R	220R	2K2	22K	220K	2M2
2R7	27R	270R	2K7	27K	270K	2M7
3R3	33R	330R	3K3	33K	330K	3M3
3R9	39R	390R	3K9	39K	390K	3M9
4R7	47R	470R	4K7	47K	470K	4M7
5R6	56R	560R	5K6	56K	560K	5M6
6R8	68R	680R	6K8	68K	680K	6M8
8R2	82R	820R	8K2	82K	820K	8M2

E24 Series:

1R0	10R	100R	1K0	10K	100K	1M0	10M
1R1	11R	110R	1K1	11K	110K	1M1
1R2	12R	120R	1K2	12K	120K	1M2
1R3	13R	130R	1K3	13K	130K	1M3
1R5	15R	150R	1K5	15K	150K	1M5
1R6	16R	160R	1K6	16K	160K	1M6
1R8	18R	180R	1K8	18K	180K	1M8
2R0	20R	200R	2K0	20K	200K	2M0
2R2	22R	220R	2K2	22K	220K	2M2
2R4	24R	240R	2K4	24K	240K	2M4
2R7	27R	270R	2K7	27K	270K	2M7
3R0	30R	300R	3K0	30K	300K	3M0
3R3	33R	330R	3K3	33K	330K	3M3
3R6	36R	360R	3K6	36K	360K	3M6
3R9	39R	390R	3K9	39K	390K	3M9
4R3	43R	430R	4K3	43K	430K	4M3
4R7	47R	470R	4K7	47K	470K	4M7
5R1	51R	510R	5K1	51K	510K	5M1
5R6	56R	560R	5K6	56K	560K	5M6
6R2	62R	620R	6K2	62K	620K	6M2
6R8	68R	680R	6K8	68K	680K	6M8
7R5	75R	750R	7K5	75K	750K	7M5
8R2	82R	820R	8K2	82K	820K	8M2
9R1	91R	910R	9K1	91K	910K	9M1

E48 Series:

The values of the decade 100-1000 for the E48 series are:

100, 105, 110, 115, 121, 127, 133, 140, 147, 154, 162, 169, 178, 187, 196, 205, 215, 226, 237, 249, 261, 274, 287, 301, 316, 332, 348, 365, 383, 402, 422, 442, 464, 487, 511, 536, 562, 590, 619, 649, 681, 715, 750, 787, 825, 866, 909, 953

Multiply or divide the values by 10 for other decades.

E96 Series:

The values of the decade 100-1000 for the E96 series are:

100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, 133, 137, 140, 143, 147, 150, 154, 158, 162, 165, 169, 174, 178, 182, 187, 191, 196, 200, 205, 210, 215, 221, 226, 232, 237, 243, 249, 255, 261, 267, 274, 280, 287, 294, 301, 309, 316, 324, 332, 340, 348, 357, 365, 374, 383, 392, 402, 412, 422, 432, 442, 453, 464, 475, 487, 491, 511, 523, 536, 549, 562, 576, 590, 604, 619, 634, 649, 665, 681, 698, 715, 732, 750, 768, 787, 806, 825, 845, 866, 887, 909, 931, 959, 976,

Multiply or divide the values by 10 for other decades.

E192 Series:

The values of the decade 100-1000 for the E192 series are:

100, 101, 102, 104, 105, 106, 107, 109, 110, 111, 113, 114, 115, 117, 118, 120, 121, 123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 142, 143, 145, 147, 149, 150, 152, 154, 156, 158, 160, 162, 164, 165, 167, 169, 172, 174, 176, 178, 180, 182, 184, 187, 189, 191, 193, 196, 198, 200, 203, 205, 208, 210, 213, 215, 218, 221, 223, 226, 229, 232, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 271, 274, 277, 280, 284, 287, 291, 294, 298, 301, 305, 309, 312, 316, 320, 324, 328, 332, 336, 340, 344, 348, 352, 357, 361, 365, 370, 374, 379, 383, 388, 392, 397, 402, 407, 412, 417, 422, 427, 432, 437, 442, 448, 453, 459, 464, 470, 475, 481, 487, 493, 499, 505, 511, 517, 523, 530, 536, 542, 549, 556, 562, 569, 576, 583, 590, 597, 604, 612, 619, 626, 634, 642, 649, 657, 665, 673, 681, 690, 698, 706, 715, 723, 732, 741, 750, 759, 768, 777, 787, 796, 806, 816, 825, 835, 845, 856, 866, 876, 887, 898, 909, 920, 931, 942, 953, 965, 976, 988

Multiply or divide the values by 10 for other decades.

Resistor Colour Code

2009-09-21T12:30:00.006+06:00

3 Band Resistor Codes:

Colour	Band 1	Band 2	Multiplier
Black	0	0	1
Brown	1	1	10
Red	2	2	100
Orange	3	3	1000
Yellow	4	4	10000
Green	5	5	100000
Blue	6	6	1000000
Violet	7	7
Grey	8	8
White	9	9

4 Band Resistor Codes:

Colour	Band 1	Band 2	Band 3	Multiplier
Black	0	0	0	1
Brown	1	1	1	10
Red	2	2	2	100
Orange	3	3	3	1000
Yellow	4	4	4	10000
Green	5	5	5	100000
Blue	6	6	6	1000000
Violet	7	7	7
Grey	8	8	8
White	9	9	9

Tolerance:

Colour:	None	Silver	Gold	Red	Brown
Tolerance:	20%	10%	5%	2%	1%

Potentiometers

2009-09-21T12:28:00.001+06:00

The most common form of rotary control on electronic equipment is the potentiometer. They are used for applications such as volume or tone controls on audio equipment and are available in panel and PCB mounting versions. A potentiometer has three terminals and is basically a variable potential divider.

Operation:

A potentiometer has a resistive track (normally made of carbon), the ends of which are connected to two of the pins (T1 and T2). The vaolue marked on a potentiomer refers to the resistance of this track. The third pin is the the 'wiper' connection (W); this touches the track at an adjustable point set by the control shaft. The internal construction of a potentiometer is shown below:

Comparing this to a potential divider circuit it can be seen that the two parts of the track either side of the wiper form R1 and R2, and the wiper provides the output from the divider.

Symbol and Connections:

The diagram below shows the standard symbol used for a potentiometer and typical connections when used as a volume control or similar. See below for details of using a potentiometer as a variable resistor:

E.G. for a linear potentiometer, if the input voltage (V_in) is 1V and the shaft is mid-way the output voltage (V_out) will be 0.5V.

Potentiometer Types:

Linear potentiometers have a constant resistance all along the track, so the output voltage is proportional to the position of the control shaft. For audio applications logarithmic types are more suitable; these have a non-linear track (supposedly logarithmic, but normally an approximation) to give a smooth response with logarithmic audio signals. Using a linear potentiometer as a volume control will give a large variation in level at one end of the rotation with little variation otherwise. Linear types are often marked A, with logarithmic types being marked B.

Other Potentiometer Configurations:

A potentiometer can be used as a variable resistor by only connecting one track connection and the wiper. In this case the resistance will be 0 at one end of the shaft's rotation, and the resistance quoted on the component at the other. Often in this configuration one end of the track is connected to the wiper instead of being left open-circuit (see diagram above).

Potential Divider

2009-09-21T01:27:00.000+06:00

A Potential (or voltage) Divider is made up of two resistors. The output voltage from a potential divider will be a proportion of the input voltage and is determined by the resistor values.

Operation:

Consider a standard resistor connected across a voltage supply. If you were able to open it up and measure the voltage at any point along it you would find the voltage varied linearly along it (assuming the resistance was constant along it's length). For example if the resistor was connected between 10V and 0V the voltage half-way along it would be 5V. Similarly the voltage 10% from the 0V end would be 1V. The diagram below illustrates this:

A potential divider works in the same way. Obviously a resistor is normally enclosed so you can't tap the voltage off at any point along it, so two resistors are used; the tap point being between these resistors. The diagram below shows a potential divider circuit with the standard component notation used:

V₁ is the voltage in and V₂ is the voltage out.

Equation:

The voltage out of the divider is determined by the resistor values using the equation:
V₂ = (R₂ / (R₁ + R₂)) * V₁

By rearranging this and specifying the total resistance (R₁ + R₂) the resistor values can be found from the desired output voltage V₂.

Phasor Diagrams

2009-09-21T01:23:00.000+06:00

Phasor diagrams can be used to represent voltages and currents in A.C. circuits. They show not only the magnitude (size) of the voltage or current, but also the phase angle of it.

See the diagrams below for some examples. Diagrams for components in series are drawn using the current as the reference phasor (since it is the same for all the components in series), those for parallel circuits use the voltage as the reference phasor.

The length of the line for each component represents the magnitude of the voltage or current, and the angle between it and the reference phasor is the phase angle.

Note that often phasor diagrams are only sketched, rather than drawn to scale!

Example:

Phase Angle in R, L & C

2009-09-21T01:22:00.000+06:00

Inductors and Capacitors, or a combination of these and resistors in A.C. circuits have a phase angle - the current is out of phase with the voltage:

Resistance:

For a resistor the current and the voltage is in phase.

Inductance:

For an inductance Voltage leads Current by 90 degrees (p / 2 radians).

Capacitance:

For a capacitance Voltage lags Current by 90 degrees (p / 2 radians).

OHM's Law

2009-09-21T01:20:00.000+06:00

This simple formula describes the relationship between voltage, current and resistance:

Voltage = Current X Resistance or V = IR
Current = Voltage / Resistance or I = V / R
Resistance = Voltage / Current or R = V / I

Ohms law can easily be remembered using the triangle below. Cover Up the value you want to find, and treat letters next to each other as multiplications, and letters above each other as divisions. Try it!

Logic Gates

2009-09-21T01:15:00.004+06:00

Logic gates give an output depending on the condition of the inputs. Below are the symbols and truth tables for the common types of logic gates. Note that due to font limitations the Boolean symbol for XOR expressed here as (+) is actually a + sign inside a circle.

AND:

A	B	Output
0	0	0
0	1	0
1	0	0
1	1	1
Expression: Output = A.B

OR:

A	B	Output
0	0	0
0	1	1
1	0	1
1	1	1
Expression: Output = A+B

XOR:

A	B	Output
0	0	0
0	1	1
1	0	1
1	1	0
Expression: Output = A(+)B

NOT:

Input	Output
0	1
1	0
Expression: Output = Input

NAND:

A	B	Output
0	0	1
0	1	1
1	0	1
1	1	0
Expression: Output = A.B

A NOT gate can be formed from a NAND gate by connecting A and B together.

NOR:

A	B	Output
0	0	1
0	1	0
1	0	0
1	1	0
Expression: Output = A+B

A NOT gate can be formed from a NOR gate by connecting A and B together.

XNOR:

A	B	Output
0	0	1
0	1	0
1	0	0
1	1	1
Expression: Output = A(+)B

A NOT gate can be formed from an XNOR gate by connecting one input to ground.

LED Current Limiting Resistor

2009-09-21T01:11:00.001+06:00

LEDs (Light Emitting Diodes) must always be operated with a resistor in series to limit the current to a safe level. Most LEDs can only tolerate a current of about 30mA maximum. To calculate the resistor value required the forward voltage (V_f) and current (I_f)of the LED must be known. These can be found from the suppliers catalogue. For standard LEDs V_f is about 2V and I_f is about 20mA.
The resistor value can be calculated as follows:

R = (V_s - V_f) / I_f

= (Supply Voltage - Forward Voltage) / Forward Current

Note that I_f is in Amps, NOT Milliamps! (20mA = 0.02A)

Kirchoff's Laws

2009-09-21T01:08:00.003+06:00

Kirchoff's voltage and current laws basically state that voltage or current in a circuit must be accounted for - it cannot just 'disappear'. The laws are as follows:

Kirchoff's Current Law:

Kirchoff's Current Law states that 'the algebraic sum of the current meeting at any point in a circuit is zero'.

For example:

I3 = I1 + I2

or I1 + I2 - I3 = 0 (currents towards point designated as positive, those away from point negative).
Kirchoff's Current Law

In other words the sum of all currents entering a junction must equal the sum of those leaving it.

Kirchoff's Voltage Law:

Kirchoff's Voltage Law states that 'in travelling round any closed mesh (section) of a network (circuit) , the algebraic sum of the emfs (voltages) acting in the mesh is equal to the algebraic sum of the IR voltage drops for the individual resistance in the mesh.'

For example:

Working anticlockwise:

IR1 + IR2 = E1 - E2

Working clockwise:

-IR1 - IR2 = E2 - E1
Kirchoff's Voltage Law

In other words the sum of all voltage sources must equal the sum of all voltages dropped across resistances in the circuit, or part of circuit.

IP Ratings

2009-09-21T01:03:00.001+06:00

IP numbers are often quoted on enclosures, connectors etc to indicate protection from solids, liquids and impact. The table below gives a description of these ratings. Note that the third number, protection against impacts, is often omitted.

IP #	First Number - Protection against solids	Second Number - Protection against liquids	Third Number - Protection against mechanical impacts (often omitted)
0	No Protection	No Protection	No Protection
1	Protected against solid objects over 50mm	Protected against vertically falling drops of water	Protected against impact of 0.225 joules
2	Protected against solid objects over 12mm	Protected against direct sprays up to 15 deg. from vertical	Protected against impact of 0.375 joules
3	Protected against solid objects over 2.5mm	Protected against direct sprays up to 60 deg. from vertical	Protected against impact of 0.5 joules
4	Protected against solid objects over 1mm	Protected against direct sprays from all directions - limited ingress permitted	Protected against impact of 2.0 joules
5	Protected against dust - limited ingress permitted	Protected against low pressure jets from all directions - limited ingress permitted	Protected against impact of 6.0 joules
6	Totally protected against dust	Protected against strong jets from all directions - limited ingress permitted	Protected against impact of 20.0 joules
7		Protected against effects of immersion from 15cm - 1m
8		Protected against long periods of immersion under pressure

DC Power

2009-09-21T01:00:00.001+06:00

Power in DC circuits is calculated in the same way as Apparent Power in AC circuits:

Power = V I

= Voltage * Current

Units are Watts (W)

This equation can be combined with Ohms Law to give an expression for the power dissipated in a resistor as:

Power = I2 R

= (Current through Resistor)2 * Resistance

Units are Watts (W)

This is derived as follows:

Power = VI

V = I R (from Ohms Law)

Combining these gives Power = I I R

or Power = I2R

Conductance

2009-09-21T00:59:00.000+06:00

Conductance is the reciprocal of resistance,

i.e. Conductance G = (1 / Resistance)

Units of Conductance are Siemens (S)

Calculating Resistors in Parallel Using Conductance:

G = G1 + G2 + G3 .....

(Total conductance is greater with more resistors in parallel so resistance is less.)

Calculating Resistors in Series Using Conductance:

(1/G) = (1/G1) + (1/G2) + (1/G3) .....

(Total conductance is less, because resistance is greater.)

Capacitor Theory

2009-09-21T00:53:00.002+06:00

A capacitor basically consists of two plates with an insulator in between, although in practice the 'plates' are normally rolled up in a can to save space. It can be used in a circuit to store charge for small periods of time.

Charge stored in a capacitor:

Charge Q = CV where C is the capacitance in Farads
charge Q is measured in coulombs (C)

Energy stored in a capacitor:

Energy stored, W = ½ QV = ½ CV² joules

Capacitance:

If the dielectric (the material between the plates) is a vacuum, Capacitance C = e₀ (A / l) where A is the area of the capacitor plates, and l is the distance between them.
e₀ is the permittivity of free space (8.85X10-12)
If the dielectric is another material, capacitance is given by:
C = e_re₀ (A / l) where e_r is the relative permittivity, which varies between materials.

Capacitors in Series:

Putting capacitors in series reduces the overall capacitance:
(1/C) = (1/C₁) + (1/C₂) + (1/C₃) .....

Capacitors in parallel:

Putting capacitors in parallel increases the total capacitance:
C = C1 + C2 + C3 .....
Note that the series and parallel capacitance formulae are the opposite of those for resistance.

Capacitor Markings

2009-09-21T00:32:00.001+06:00

Capacitors are often marked with codes to show the value, tolerance and material. This is particularly true for small types such as ceramic disc or polystyrene where there is little space for full markings.

Value Codes:
The capacitance value is often marked using a 3 digit code. This works in the same way as resistor coding but using numbers instead of colours. The first 2 numbers give the value and the last number is the multiplier. These give the value in Picofarads (pF), e.g. code 103 = 1 0 000pF (=0.01uF - see Capacitance Conversion Table). Alternatively the value may be marked directly, for example 2n2 is 2.2 Nanofarads (nF).

Tolerance Code:
A single letter is often used to indicate the tolerance of the component. These can be translated using the following table:

Tolerance Code	Tolerance
C	+/- 0.25pF
D	+/- 0.5pF
F	+/- 1%
G	+/- 2%
J	+/- 5%
K	+/- 10%
M	+/- 20%
Z	- 20% +80%

Material Code:

The dielectric material is often marked in abbreviated form. The table below shows the meaning of these abbreviations.

Marking	Material
MKT	Metallised Polyester (PETP)
MKC	Metallised Polycarbonate
KT	Polyester Film / Foil
KS	Polystyrene Film / Foil
KP	Polypropylene Film / Foil
MKP	Metallised Polypropylene

Capacitance Conversion Table

2009-09-21T00:22:00.002+06:00

Different types of capacitors often have their values marked in different orders of magnitude. It is sometimes necessary to convert between them:

Microfarads (mF)	Nanofarads (nF)	Picofarads (pF)
0.000001	0.001	1
0.00001	0.01	10
0.0001	0.1	100
0.001	1	1000
0.01	10	10000
0.1	100	100000
1	1000	1000000
10	10000	10000000
100	100000	100000000

Approvals Markings on Equipment

2009-09-20T22:58:00.004+06:00

Commercially manufactured equipment often has markings on it to show compliance with approvals for certain countries. The table below shows what these markings stand for.

ASTA (UK)

NEMKO (Norway)

BASEC (UK)

NF-USE (France)

BEAB (UK)

OVE (Austria)

BSI (UK)

SECV (Australia)

CEBEC (Belgium)

SEMKO (Sweden
)

CSA (Canada)

SETI (Finland)

DEMKO(Denmark)

SEV (Switzerland)

GOST (USSR)

UL (USA)

IMQ (Italy)

VDE (Germany)

KEMA-KEUR (Holland)

AC Power

2009-09-20T22:40:00.000+06:00

Apparent Power, S - appears on the hypotenuse of the power triangle.

Apparent power is given by:

Apparent power = V I

= Voltage * Current

Units are volt -amps (VA)



True Power, P - appears on the adjacent of the power triangle

True power is given by:

I2R = S cos f = VI cos f

This is the power in the resistive part of the circuit

Units are Watts (W)



Reactive Power, Q - appears on the opposite of the power triangle

Given by:

I2XL = S sin f = VI sin f

and: I2XC = S sin f = VI sin f

where XL and XC are inductive reactance and capacitive reactance respectively, and f is the phase angle.

Units are volt-amps reactive (VAr)



Power Factor:

Power Factor = True Power / Apparent Power = P / S = cos f

True Power = Apparent Power * Power Factor

= VI cos f

Technical Data

2009-09-20T22:25:00.003+06:00

The Technical Data Archive contains information including component theory, colour codes, conversion charts and more. All the articles can be accessed from the index below.

The 'Pin-Out' section has pin connection and package details for connectors and components. Each article includes pin assignments, applications, assembly instructions and more, and can be accessed from the main menu or the link below.

The information here is added to and updated occasionally, so Bookmark http://eestudenthelp.blogspot.com/ And keep visiting for updates.

A-Z Index of Articles:

AC Power

Approvals Markings on Equipment

Capacitance Conversion Table

Capacitor Markings

Capacitor Theory

Conductance

DC Power

IP Ratings

Kirchoff's Laws

LED Series Current Limiting Resistor

Logic Gates & Truth Tables

Ohm's Law

Phase Angle in R, L and C

Phasor Diagrams

Potential Divider

Potentiometers

Resistor Colour Codes

Resistors - Preferred Values

Resistor Theory

Resistors, Capacitors and Inductors in A.C. circuits

R.M.S. Values

Series combinations of R, C and L in A.C. circuits

SI Units

WEEE / RoHS Directives

Wheatstone Bridge

Series-Parallel combination of Resistors Value Calculator

2009-09-20T18:10:00.022+06:00

Series/Parallel Array of LEDs Current Limiting Resistor Value Calculator

2009-09-20T17:12:00.005+06:00

The LED series/parallel array wizard is a calculator that will help you design
large arrays of LEDs. The LED calculator was great for single LEDs--but when
you have several, the wizard will help you arrange them in a series or combined
series/parallel configuration. The wizard determines the current limiting resistor
value for each portion of the array and calculates power consumed. All you need
to know are the specs of your LEDs and how many you'd like to use.

LED Current Limiting Resistor Value Calculator

2009-09-20T17:03:00.001+06:00

When you have a single LED and need to know "what resistor should I use with my LED?" This calculator determines that for you.

External Links / Softwares

2009-09-20T12:44:00.008+06:00

The following are links to sites that provide resources for science, electronics projects and other relevant information.

MASM V6.11 *NEW

Boson Network Simulator 7 for CCNP
Software for simulating Networks Administration

Super Science Fair Projects eBook
Detailed, step-by-step instructions on how to do an award winning science fair project. A Parent's Guide. Live links to a resource page. Instantly Downloadable.

Electronics Engineering Career
Are you fascinated with the world of electronics? If you are, you may want to consider electronics engineering as your career. Find out what a product development
electronics engineer can do.

Easy low cost projects for the home handyman
Build a solar pool heater, a kids electric go kart, garden sheds, skateboard ramps, an electric supercharger and much more.

Directory Science
The online Science directory designed to help users find the online science source, electronics projects, companies, products, services, and information.

Techlearner
We provide for Electronics and Technology Basics Learning : Basic Electronics subjects, Electronics Companies, latest Electronics News, Application Notes, Dictionaries, Tutorials, Reference Links, Circuits and Datasheets.

Dontronics
This site has a good range of Atmel/AVR & PICmicro Hardware and Software products.

Electronic Kits
Carl's Electronics - Hundreds of electronic kits, electronic circuits, plans and much more.

Electronics 2000
For electronics hobbyists, engineers and students. Online calculators, software downloads, technical data, beginners guide, pinouts, forum, links and more!

Electronic Tools

2009-09-20T11:31:00.007+06:00

Basic Electronic Tools used to assemble electronic projects and electronic kits

Introduction to Basic Electronic Tools

Assembling electronics project and making it works is a good start in helping one to learn troubleshooting methods as
well as becoming familiar with your tools, test equipments, electronic schematics and component color codes.

It's hard to do a good job of electronics construction unless proper electronic tools and knowledge of using them are adequate.
Some of the basic tools that should prove useful are listed below.

Electric Drill and Drill Bits

Electric drill and drill bits in the range of 1/8 inch to 1/2 inch will come in handy when you need to drill holes on
the printed circuit board that has been etched. Drilling of plastic or metal enclosure that houses the printed
circuit board are sometimes necessary. A suitable PCB high speed drill can be easily obtained from any electronic
shop.

Soldering Iron

A 20 Watt to 30 Watt soldering iron with tips of 1/8 inch to 1/2 inch can be used for soldering of through hole
components. Soldering of surface mount components may require smaller tips depending on the sizes of the components.
Soldering iron normally will last a long time if it is taken care of properly by keeping the tips clean and well tinned.

Wire Stripper

Wire stripper is used to strip off wire insulator from its conductor before it is used to connect to another wire or
soldered into the printed circuit board. Some wire stripper or wire cutter has a measurement engraved on it to indicate
the length that will be stripped.

Long nose Plier

A 4-inch long nose plier will come in handy when you need to hold components that have short leads that need to be
soldered onto the PCB but will be too hot to handle with bare hands. It will also be useful to hold the component
that needs to be de-soldered from the board.

Side-Cutting Plier

A 4-inch side cutting plier will come in handy as one of the electronic tools when one need to trim off excess component leads on the printed
circuit board. It can also be used to cut wires into shorter length before being used.

Tweezers

Small tweezer is used to hold small components especially when doing soldering and de-soldering of surface mount
components.

Allen Wrench set

Allen wrench set is sometimes used to unscrew or screw Allen type of screws.

Philips Head Screwdrivers

Various sizes of Philips head screwdrivers will be handy as a lot of electronics projects that use screws are Philips
Head type.

Flat Head Screwdrivers

Flat head screwdrivers of various sizes are also necessary as many screws that are used are of this type.

Hammer

A small, light hammer will be useful when assembling projects that involved casing.

Socket wrench sets

A socket wrench sets that include nut drivers, hex drivers, and starters in assorted sizes will come in handy during the assembly work of electronics project.

Pocket Knife

Pocket Knife will be useful when one need to cut PCB, wires or remove some cooper from the printed circuit board.

Maintenance Tips Of Electronic Tools

Good quality tools that are being purchased can last a lifetime if they are taken care of properly. Ensure
that the tools are used only for their intended purposes, keep them lubricated with a light film of oil to inhibit
rust, keep the tools clean and sharp, keep the soldering tips clean and well tinned and ensure that proper use of
the tools are always adhered to by following the instructions of using the tools.

Articles & Basic Concepts

2009-09-20T02:19:00.002+06:00

COMING SOON !!!

Includes Article on Topics relating to Electronic Engineering Courses, which are often difficult to understand for the EE STUDENTS.
The Articles are intended to make concepts based on examples and analogies.

Please Keep Visiting For Updates.

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2009-09-20T02:14:00.000+06:00

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2009-09-19T01:03:00.019+06:00

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Request : EBook : Tutorial : Article

2009-08-24T17:32:00.006+06:00

Make your requests for Ebooks, Tutorials, Guides, Articles, Explanation of any topic related to Electronic Engineering BELOW...

How to Reflow a Connection in an Electronic Circuit

2009-08-24T16:26:00.010+06:00

How to De-solder Electronic Connections

2009-08-24T16:26:00.009+06:00

How Transistors Work in an Electronic Circuit

2009-08-24T16:25:00.031+06:00

How to Use a Breadboard to Prototype a Circuit Board

2009-08-24T16:25:00.030+06:00

How Soldering Irons Work

2009-08-24T16:25:00.029+06:00

How to Use Integrated Circuits

2009-08-24T16:25:00.028+06:00

How a Variable Resistor Works in an Electronic Circuit

2009-08-24T16:25:00.027+06:00

How Switches Open & Close Circuits

2009-08-24T16:25:00.026+06:00

Soldering Iron Maintenance Tips

2009-08-24T16:25:00.025+06:00

Heating & Applying Solder

2009-08-24T16:25:00.024+06:00

How Capacitors Work in Electronic Circuits

2009-08-24T16:24:00.011+06:00

Differences in Wire Gauges

2009-08-24T16:24:00.010+06:00

How Does a Series Circuit Work

2009-08-24T16:24:00.009+06:00

Practical Operation of Electronic Circuit Indicators

2009-08-24T16:22:00.027+06:00

How to Use Perfboard to Make an Electronic Circuit

2009-08-24T16:22:00.026+06:00

How Printed Circuit Boards Work

2009-08-24T16:22:00.025+06:00

How to Make a Schematic for Your Electronic Circuit Project

2009-08-24T16:22:00.024+06:00

How Schematics are Used in Electronics

2009-08-24T16:22:00.023+06:00

How to Test a Prototype of Your Electronic Circuit

2009-08-24T16:22:00.022+06:00

Color Codes for Resistors in Electronic Circuits

2009-08-24T16:21:00.011+06:00

How to Measure Current in a Circuit

2009-08-24T16:21:00.010+06:00

How to Measure Components in an Electronic Circuit

2009-08-24T16:21:00.009+06:00

Video Tutorials

2009-08-24T01:19:00.031+06:00

Here, you will find a lot of VIDEO TUTORIALS related to Electronics.

Color Codes for Resistors in Electronic Circuits

How to Measure Current in a Circuit

How to Measure Components in an Electronic Circuit

How to Make a Schematic for Your Electronic Circuit Project

How Schematics are Used in Electronics

Practical Operation of Electronic Circuit Indicators

How to Use Perfboard to Make an Electronic Circuit

How Printed Circuit Boards Work

How to Test a Prototype of Your Electronic Circuit

Differences in Wire Gauges

How Capacitors Work in Electronic Circuits

How Does a Series Circuit Work

How Transistors Work in an Electronic Circuit

How to Use a Breadboard to Prototype a Circuit Board

How to Use Integrated Circuits

How a Variable Resistor Works in an Electronic Circuit

How Switches Open & Close Circuits

How Soldering Irons Work

Heating & Applying Solder

Soldering Iron Maintenance Tips

How to De-solder Electronic Connections

How to Reflow a Connection in an Electronic Circuit

Magazines

2009-08-24T00:59:00.005+06:00

COMING SOON !!!

Please Keep Visiting For Updates.

Engineering EBOOKS IV : Manual Solutions of Books

2009-08-24T00:58:00.018+06:00

Solutions Of the Following Books are Available :

Introduction To VLSI Circuits & Systems by John P. Uyemura

Probability and Statistics for Engineers by walpole

Computer Architectur and Organiztion
by William Stalling - 7th Edt

Digital Design 4th Edt Morris Mano

Engineering Circuit Analysis 6th ed - William Hayt

Engineering Electromagnetics 6th ed - William Hayt

Engineering Electromagnetics 7th ed William Hayt

Electronic devices and circuit theory 8th ed - Boylestad

Advanced Engineering Mathematics 8th ed by Erwin KreyszigDigital_Signal_Processing Proakis Manolakis 3rd ed Solution

Projects , Circuit Diagrams Collection

2009-08-22T00:58:00.044+06:00

NEW COLLECTION OF PROJECTS AND CIRCUIT DIAGRAMS COMING SOON!!

Please Keep Visiting for UPDATES.

ELECTRONIC GADGETS FOR THE EVIL GENIUS--28 DIY PROJECTS

Opamp circuit collection

30 projects using picbasic and pic basic pro by D.Ibrahim Newnes 2006

Solary Energy Projects for the Evil Genius - 50 Projects

Many More Latest & NEW Collection of Projects & Circuit Diagrams Coming Soon!!!

Please Keep Visiting for UPDATES.

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	ASTA (UK)		NEMKO (Norway)
	BASEC (UK)		NF-USE (France)
	BEAB (UK)		OVE (Austria)
	BSI (UK)		SECV (Australia)
	CEBEC (Belgium)		SEMKO (Sweden )
	CSA (Canada)		SETI (Finland)
	DEMKO(Denmark)		SEV (Switzerland)
	GOST (USSR)		UL (USA)
	IMQ (Italy)		VDE (Germany)
	KEMA-KEUR (Holland)