NOT gates

The NOT gate has a single input and one output.

The little bubble on the output indicates that the output goes LOW when the input goes HIGH.

We can say that the output goes LOW when the input is ACTIVATED.

The opposite happens when the input is LOW. The output goes HIGH.

The TRUTH TABLE shows that the output is the opposite of the input.

The NOT gate is also called an INVERTER. It inverts the input.
_
The Boolean expression is A = Z

Which is read as, NOT A EQUALS Z

or IF A IS LOW THEN Z IS HIGH

or BAR A = Z

OR gates

The OR gate has two or more inputs and one output.

The output voltage goes high only when one or more input voltages are high.

In the switch diagram the lamp lights up when A OR B (or both) are operated.

In the truth table Z = 1 when A or B = 1.

The Boolean expression is A+B = Z which translated says, A or B high makes Z high.

The plus sign + translates as OR.

 

AND Gates

The AND gate has two or more inputs and one output.

The output voltage goes high only when all input voltages are high.

In the switch diagram the lamp lights up only when A and B are operated. If only one is switched then the lamp stays off.

In the truth table Z = 1 only when A and B = 1

The Boolean expression is A. B = Z which translated says, A and B both high, makes Z high.

 

Binary

In 1854, a central paper on binary systems was published by the mathematician George Boole. This paper laid out the groundwork for what would eventually be called Boolean algebra. With the advent of electronics, binary systems suddenly made incredible sense. Most electronic systems function on a switch-based system, with current either running or not running. In 1937, Claude Shannon set out the foundations for the theory of circuit design using binary arithmetic. In 1940, the age of binary computing began with the release of Bell Labs Complex Number Computer, which was able to perform extremely complex mathematical calculations using a binary system.
Binary numbers (1 or 0) represent on(1) or off(0).

Typically you work out binary like this:

256 128 64 32 16 8 4 2 1

If you have say a decimal number of 254, to work out the binary code you would use the system above to work it out. So,

256 128 64 32 16 8 4 2 1

0 1 1 1 1 1 1 1 0

The number that was given (254) is equated in the system above if you were to add up the numbers that have 1s underneath them.From there you can learn to translate binary into decimal, decimal into hexidecimal (not using binary,because hex is a whole other language base) which then goes onto C++ programming and all the rest.

If you're working out bigger numbers, for instance 3813, then you need to create a bigger system in order to work out the binary code so therefore you need to do this:

2048 1024 512 256 128 64 32 16 8 4 2 1

1 1 1 0 1 1 1 0 0 1 0 1

So this is your Binary Code for 3813:

1 1 1 0 1 1 1 0 0 1 0 1

If you want to be lazy you can just use your calculator on your computer. You need to switch the view to scientific which calculates binary, decimal, hex and octal. I suggest you make sure you understand binary code first before moving onto hex because the development between them can become very confusing.

Sound Effects Generator

Description:
This circuit uses a UM3561 IC to produce four different sound effects.

Notes:
Nothing too complicated here. The IC produces all the sound effects, the output at Pin 3 being amplified by the transistor. A 64 ohm loudspeaker can be substituted in place of the 56 ohm resistor and 8 ohm loudspeaker. The 2 pole 4 way switch controls the sound effects. Position 1 (as drawn) being a Police siren, position 2 is a fire engine sound, 3 is an ambulance and position 4 is a machine gun effect. The IC is manufactured by UMC and was available from Maplin electronics code UJ45Y. At the time of writing this has now been discontinued, but they have have limited stocks available.

24 Hour Timer Circuit

Circuit : Thelurunk
Description:
These two circuits are multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is running; and the second uses less power after the timer stops. Pick the one that best suits your application.

 

 

The Cmos 4060 is a 14 bit binary counter with a built in oscillator. The oscillator consists of the two inverters connected to Pins 9, 10 & 11; and its frequency is set by R3, R4 & C3. The green Led flashes while the oscillator is running: and the IC counts the number of oscillations. Although it's a 14 bit counter, not all of the bits are accessible. Those that can be reached are shown on the drawing.

By adjusting the frequency of the oscillator you can set the length of time it takes for any given output to go high. This output then switches the transistor; which in turn operates the relay. At the same time, D1 stops the count by disabling the oscillator. Ideally C3 should be non-polarized; but a regular electrolytic will work, provided it doesn't leak too badly in the reverse direction. Alternatively, you can simulate a non-polarized 10uF capacitor by connecting two 22uF capacitors back to back (as shown).

Using "Trial and Error" to set a long time period would be very tedious. A better solution is to use the Setup tables provided; and calculate the time required for Pin 7 to go high. The Setup tables on both schematics are interchangeable. They're just two different ways of expressing the same equation.

For example, if you want a period of 9 Hours, the Range table shows that you can use the output at Pin 2. You need Pin 2 to go high after 9 x 60 x 60 = 32 400 seconds. The Setup table tells you to divide this by 512; giving about 63 seconds. Adjust R4 so that the Yellow LED lights 63 seconds after power is applied. This will give an output at Pin 2 after about 9 Hours. A suitable Veroboard layout for each version is shown below:
 

How to make Electronic Siren Circuit

The sound produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors is discharged and both transistors are off. When the push button switch is pressed to 10u capacitor will charge via the 22k resistor. This voltage is applied to the base of the BC108B which will turn on slowly. When the switch is released the capacitor will discharge via the 100k and 47k base resistors and the transistor will slowly turn off. The change in voltage alters the frequency of the siren. The oscillator action is more difficult to work out. As the BC108B transistor switches on its collector voltage falls and so the 2N3702 transistor is switched on. This happens very quickly ( less than 1us). The 22n capacitor will charge very quickly as well. As this capacitor is connected between the collector of the 2N3702 and the base of the BC108B, it soon reaches almost full supply voltage. The charging current for the capacitor is then much reduced and the collector emitter voltage of the 2N3072 is therefore increased; the collector potential will fall. This change in voltage is passed through the 22n capacitor to the base of the BC108B causing it to come out of saturation slightly. As this happens its collector voltage will rise and turn off the 2N3072 transistor more. This continues until both transistors are off. The 22n capacitor will then discharge via the 100k, 22k resistor, the closed push button switch, 9V battery, the speaker and 56 ohm resistor. The discharge time takes around 5-6msec. As soon as the 22n capacitor is discharged, the BC108B transistor will switch on again and the cycle repeats. The difference in voltage at the collector of the BC108B (caused by the charging 10u capacitor) causes the tone of the siren to change. As the 10u capacitor is charged, the tone of the siren will rise, and as it is discharged, it will fall. A 64 ohm loudspeaker may be used in place of the 8 ohm and 56 resistor, and the values of components may be altered to produce different sound effects.

About Zener Diode

The Zener diode is operated in reverse bias mode (positive on its cathode).
It relies on the reverse breakdown voltage occurring at a specified value.
This value is printed on it.

It has two main applications.

1. as a reference source, where the voltage across it is compared with another voltage.

2. as a voltage regulator, smoothing out any voltages variations occurring in the supply voltage across the load.

When being used a voltage regulator, if the voltage across the load tries to rise then the Zener takes more current.
The increase in current through the resistor causes an increase in voltage dropped across the resistor.
This increase in voltage across the resistor causes the voltage across the load to remain at its correct value.

In a similar manner, if the voltage across the load tries to fall, then the Zener takes less current.
The current through the resistor and the voltage across the resistor both fall.
The voltage across the load remains at its correct value.

Series Parallel Batteries

Resistors in Parallel

Resistors in parallel are connected across one another.
They all have the same voltage across them.

To find the equivalent resistance (the total resistance offered to the flow of current) we invert the values and add them. Then we invert the result.

For example take 2 ohms and 4 ohms in parallel.

Inverted 1/2 +1/4 = 3/4

Invert this 4/3 = 1.33 ohms

A quick check on your answer is that it should be smaller in value than the value of the smallest resistor.

If these resistors were connected across a 10 volt supply Ohms Law says about 7.5 amps would flow.

The formula can be written as 1/Rtotal = 1/R1 + 1/R2 + 1/R3 etc etc.

If only two resistors are involved then use (R1 x R2) divided by (R1 + R2)
For the 2 ohms and 4 ohms.
R1 x R2 = 8.
R1 + R2 = 6.
8/6 = 1.33 ohms

If you have several resistors of the same value in parallel then the equivalent resistance is the resistor value divided by the number of resistors.
For example, four 100 ohm resistors in parallel will provide a resistance of 25 ohms

How to make Resistors in Series

Resistors in series are connected in line.

The same current flows through them all.

The total opposition to the flow of current is called the EQUIVALENT resistance.
To find the value of the equivalent resistance we simply add the values.
In this case it is 30 ohms.

Note that, as a quick check on calculations, the value of the equivalent resistance is always higher than the value of the highest value resistance.

If these resistors were connected across a 30 Volt battery then Ohms Law says 1 amp would flow.

Electric Current

An electric current is a flow of microscopic particles called ELECTRONS flowing through wires and electronic components.
It can be likened to the flow of water through pipes and radiators etc.
As water is pushed through pipes by a pump, electric current is pushed through wires by a battery.
Hot water does work by heating radiators.
Electric current does work by heating fires, lighting lamps, ringing bells, electroplating etc.

A basic law of the universe is that like charges repel and unlike attract. Two negatives will repel each other. A negative and a positive will attract each other.
An electron has a negative charge.
The negative (-ve) terminal of a battery will push negative electrons along a wire.
The positive (+ve) terminal of a battery will attract negative electrons along a wire.

Electric current will therefore flow from the -ve terminal of a battery, through the lamp, to the positive terminal.

This is called electron current flow.

The current flows round the circuit.

In some books current is said to flow from +ve to -ve. This was guessed at before the electron was discovered. They guessed wrong! This is called conventional current flow.

Welcome

THIS ELECTRONICS TUTORIALS SITE

Dear Visitors, This site  offered   FREE to you and are extremely comprehensive with over 120 individual electronics tutorials topics covering a very wide range of electronics. It will always continue to expand so come back often. This page will give you a good broad overview of this very comprehensive electronics tutorials site.
NAVIGATING THIS SITE

So you don't become confused, this site is largely set up on a basis of "directories". On the left hand side are "clickable" navigation links which take you to things like basic electronics, antennas, amplifiers, data sheets, downloads, filters, oscillators and receivers etc. Each directory has its own navigation bars to different topics under that general heading. Also each topic has at the end, and indeed often throughout the topic, related topic links. It's that easy. If you haven't already done so, I suggest you right click your mouse now and "create a short cut" for your desktop or bookmark this site.

4 channels mixer voltage controlled

The audio mixer schematic we propose is developed arround 4 amplifiers build inside SSM2024 produced by Precision Monolithics Inc. (PMI) and is voltage controlled (VR).

The maximum VR voltage is 5.5Volt. The signal/noise ratio is 90dB and 130Khz band wide. This 4 channels mixer works great at +- 15Volt but you can use voltages between 9Volt and 18Volt.
4 channels mixer voltage controlled
Audio mixer circuit schematic

1.2 volts power supply

This switch mode power supply circuit require an input voltage range , between 4.5V to 16V,and will provide a very stable output voltage of 1.2 volt . The LTM4627 supports an output voltage range of 0.6V to 5V, set by a single external resistor , so you can modify the output voltage .


High switching frequency and a current mode architecture enable a very fast transient response to line and load changes without sacrificing stability.
 

1.2 volts power supply

Variable switching power supply using LM317

Another power supply electronic circuit that is designed using LM317 voltage regulator can be designed using few electronic parts . This power supply circuit is a very simple low cost switching regulator electronic project that is based on the LM317 three terminal regulator .


As you can see in the circuit diagram this power supply electronic project require few external components and a LM317HV regulator . The input voltage required by this electronic project must be between 8 and 35 volt , and will provide a variable output voltage over a wide range , from 1.8 volts up to 32 volts
The maximum output current that can be delivered by this LM317HV switching power supply electronic project is up to 3 amperes .


C1 , C4 capacitors must be a solid tantalum type and L1 coil must have a 600uH inductance . For L1 coil you can use a Arnold A-254168-2 core with 60 turns .
 

 
 
 
 
 
 
 
 
 
 
 
source:http://www.electroniq.net

UM3561 electronic siren circuit diagram

This siren alarm circuit diagram is based on a specialized IC UM3561 , which is a low power CMOS LSI specially designed for this type of applications . The UM3561 contains all needed parts ( oscillator , selector circuits , programmed mask ROM ) to simulate siren sound using few external components .


The siren circuit require a power supply circuit around 3 volts and has a low current . The UM3561 siren sound generator circuit has possibility to generate four types of sounds : police siren , fire engine siren , ambulance siren and machine gun sound .
 
The transistor used in this project must be 2SC9013 , 2SC8050 or similar type .
 

The speaker used at the output must have 8 ohms impedance and a 0.2 watts power .

As you can see in these three circuit diagrams , the configuration for the siren is very simple .
UM3561 electronic siren circuit diagram
Police siren , fire engine siren , ambulance siren and machine gun sound .

Police siren , fire engine siren , ambulance siren .

 
 
 
 
 
 
 
 
Police siren and machine gun sound .
 

source :http://www.electroniq.net

Simple mixer circuit – Common base

The simple mixer schematic is built on common base principle, where input voltages are transformed in alternative currents wich are summed to form the alternative current component for the collector. The total amplification is R6 - Ri, where Ri is one of the input resistors. I’ve build this mixer for a little transmitter and works great.

Simple mixer circuit – Common base

Simple mixer circuit – Common base
source :http://electroschematics.com

Simple mixer circuit * Common base

IRF740 Datasheet , power MOSFET

N - CHANNEL 400V - 0.48 Ω - 10 A - TO-220
PowerMESH MOSFET

This power MOSFET is designed using the company’s consolidated strip layout-based MESH OVERLAY process. This technology matches and improves the performances compared with standard parts from various sources.

APPLICATIONS
# HIGH CURRENT SWITCHING
# UNINTERRUPTIBLE POWER SUPPLY (UPS
# DC/DC COVERTERS FOR TELECOM,
# INDUSTRIAL, AND LIGHTING EQUIPMENT

 MOSFET, N, 400V, 10A, TO-220; Transistor Type:MOSFET; Transistor Polarity:N; Voltage, Vds Typ:400V; Current, Id Cont:10A; Resistance, Rds On:0.55ohm; Voltage, Vgs Rds on Measurement:10V; Voltage, Vgs th Typ:4V; Case Style:TO-220AB; Termination Type:Through Hole; Current, Idm Pulse:40A; Power Dissipation:125W; Power, Pd:125W; Thermal Resistance, Junction to Case A:1 C/W; Voltage, Vds Max:400V

  search keyword :
IRF740, IRF740 Datasheet, IRF740 MOSFET N Channel Transistor, IRF740

download datasheet 

Power MOSFET IRFP264, SiHFP264 datasheet

Third generation Power MOSFETs from Vishay provide the designer with the best combination of fast switching,
ruggedized device design, low on-resistance and cost-effectiveness.
The TO-247 package is preferred for commercial-industrial applications where higher power levels preclude the use of TO-220 devices. The TO-247 is similar but superior to the earlier TO-218 package because its isolated mounting hole.
It also provides greater creepage distances between pins to meet the requirements of most safety specifications.

FEATURES


• Dynamic dV/dt Rating
• Repetitive Avalanche Rated
• Isolated Central Mounting Hole
• Fast Switching
• Ease of Paralleling
• Simple Drive Requirements
• Lead (Pb)-free Available


Maximum Power Dissipation = 280w
Drain-Source Voltage = 250v
Gate-Source Voltage = ± 20

ORDERING INFORMATION :

Package : TO-247

Lead (Pb)-free : IRFP264PbF , SiHFP264-E3 .

SnPb : IRFP264 , SiHFP264 .


search keyword :
IRFP264 datasheet, IRFP264 circuit, IRFP264 data shee Power MOSFET

download datasheet 

IRFP250 free Datasheet

33A, 200V, 0.085 Ohm, N-Channel
Power MOSFET

This N-Channel enhancement mode silicon gate power field effect transistor is an advanced power MOSFET designed, tested, and guaranteed to withstand a specified level of energy in the breakdown avalanche mode of operation. All of these power MOSFETs are designed for applications such as switching regulators, switching convertors, motor drivers,
relay drivers, and drivers for high power bipolar switching transistors requiring high speed and low gate drive power.
These types can be operated directly from integrated circuits Formerly developmental type TA9295.

IRFP250 FET 200V 33A 180W

IRFP250

Features

• 33A, 200V
•rDS(ON) = 0.085Ω
• Single Pulse Avalanche Energy Rated
• SOA is Power Dissipation Limited
• Nanosecond Switching Speeds
• Linear Transfer Characteristics
• High Input Impedance
• Related Literature
- TB334 “Guidelines for Soldering Surface Moun
Components to PC Boards”

search keyword :

Power MOSFET. IRFP250 , IRFP250 datasheet,IRFP250 Pinout , IRFP250 MOSFET N Channel Transistor,

download datasheet 

str6707

The STR-S6707, STR-S6708, and STR-S6709 are specifically designed to meet the requirement for increased integration and reliabil- ity in off-line quasi-resonant flyback converters.  These devices incorpo-
rate the primary control and proportional drive circuit with a third- generation high-voltage bipolar switching transistor.

Crucial system parameters such as maximum ON time and OFF
time are fixed during manufacture.  Local control circuit decoupling and
layout are optimized within each device.
Cycle-by-cycle current limiting, under-voltage lock-out with hyster-
esis, over-voltage protection, and thermal shutdown protect these
devices during all normal and overload conditions.  Over-voltage
protection and thermal shutdown are latched after a short delay.  A
versatile triple-level inhibit circuit includes the OFF time synchronization
required to establish quasi-resonant operation.  The inhibit function has
also been expanded to initiate operation in stand-by mode in which the
power supply delivers a small fraction of the steady-state output power.
The dual requirements of dielectric isolation and low transient thermal
impedance and steady-state thermal resistance are satisfied in an over-
molded single-in-line power package.
Proven in substantial volumes, these devices and their fixed-
frequency counterparts represent a significant advance in off-line SMPS
reliability growth and integration.


FEATURES
  Quasi-Resonant Operation for Low EMI and High Efficiency
  Output Power to 220 W
  Low-Power Output Standby Mode
  Pulse-by-Pulse Over-Current Protection
  Latched Over-Voltage and Thermal Protection
  Third-Generation Switching Transistor with Proportional Drive
  Maximum ON Time and Off Time Set During Manufacture
  Internal Under-Voltage Lockout with Hysteresis
  Over-Molded SIP with Integral Isolated Heat Spreader

 OFF-LINE SWITCHING REGULATORS – WITH BIPOLAR SWITCHING TRANSISTOR
STR6707 datasheet, STR6707 datasheets, STR6707 datenblatt, STR6707

 http://www.tube-tester.com/sites/nixie/nixie-clock-cd47/data/STRS6707.pdf

LM49155 Uplink Noise Suppression & Downlink SNR Enhancement Analog Audio Subsystem

Features
Noise cancellation for uplink and downlink without DSP-type artifacts, distortions or delays
Adapting AGC on ambient noise level & downlink signal strength for earpiece
Downlink adjustable noise-reducing high pass filter
E 2S Class D Amplifier with ALC
Ground Referenced Headphone Outputs with Advanced Click Pop Suppression
Micro-power shutdown

Description

The LM49155 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones. The LM49155 combines a Noise Suppression microphone amplifier, a 1.35W mono class D amplifier with ALC, class AB earpiece driver with AGC, a high efficiency, stereo, ground referenced headphone amplifier with click pop suppression and I 2C modes select and volume control.

The LM49155 features analog fully differential input, and differential output microphone amplifier designed to reduce background acoustic noise, while delivering superb speech clarity in voice communication applications. Downlink SNR enhancement with an advanced acoustic AGC technology to adjust output levels.

The LM49155 speaker amplifier features National’s unique output limiter that provides both a no-clip feature and speaker protection. The E 2S class D amplifier features a patented, ultra low EMI PWM architecture that significantly reduces RF emissions while preserving audio quality and efficiency. The headphone drivers feature National’s ground referenced architecture that creates a ground-referenced output from a single, low-voltage supply.


Applications
Mobile Phones
Portable Electronic Devices

download lm49155 datasheet

Mono Class D Audio Codec Subsytem with Ground Referenced Headphone Amplifiers

Features

Ultra efficient, spread spectrum Class D loudspeaker amplifier that operates at 93% efficiency
Low voltage, true ground headphone amplifier operation
High performance 103dB SNR stereo DAC
High performance 97dB SNR stereo ADC
Up to 96kHz stereo audio playback
Up to 48kHz stereo recording
Dual bidirectional I 2S or PCM compatible audio interfaces
Read/write I 2C compatible control interface
Flexible digital mixer with sample rate conversion
Sigma-delta PLL clock network that supports system clocks up to 50MHz including 13MHz, 19.2MHz, and 26MHz
Dual stereo 5 band parametric equalizers
Cascadable DSP effects that allow stereo 10 band parametric equalization
ALC/Limiter/Compressor on both DAC and ADC paths
Dedicated Earpiece Speaker Amplifier
Stereo auxiliary inputs and mono differential input
Differential microphone input with single-ended option
Automatic level control for digital audio inputs, mono differential input, microphone input, and stereo auxiliary inputs
Flexible audio routing from input to output
16 Step volume control for microphone with 2dB steps
32 Step volume control for auxiliary inputs in 1.5dB steps
4 Step volume control for class D loudspeaker amplifier
8 Step volume control for headphone amplifier
Micro-power shutdown mode
Available in the 3.3 x 3.3 mm 36 bump micro SMD package

Description
The LM49352 is a high performance mixed signal audio subsystem. The LM49352 includes a high quality stereo DAC, a high quality stereo ADC, a stereo headphone amplifier, which supports True Ground operation, a low EMI Class D loudspeaker amplifier, and an earpiece speaker amplifier. It combines advanced audio processing, conversion, mixing, and amplification in the smallest possible footprint while extending the battery life of feature rich portable devices.
The LM49352 features dual bi-directional I 2S or PCM audio interfaces and an I 2C compatible interface for control. The stereo DAC path features an SNR of 103dB with 24-bit 48 kHz input. The headphone amplifier delivers 65mWRMS (typ) to a 32Ω single-ended stereo load with less than 1% distortion (THD+N) when HP_VDD = 2.8V. The loudspeaker amplifier delivers up to 970mW into an 8Ω load with less than 1% distortion when LS_VDD = 4.2V.
The LM49352 employs advanced techniques to extend battery life, to reduce controller overhead, to speed development time, and to eliminate click and pop artifacts. Boomer audio power amplifiers are designed specifically for mobile devices and require minimal PCB area and external components.

Applications
Smart Phones
Mobile Phones and VOIP Phones
Portable GPS Navigator and Portable Gaming Devices
Portable DVD/CD/AAC/MP3/MP4 Players
Digital Cameras/Camcorders


download datasheet from http://www.national.com/

MAX515 5V, Low-Power, Voltage-Output, Serial, 10-Bit DACs

The MAX504/MAX515 are low-power, voltage-output, 10-bit digital-to-analog converters (DACs) specified for single +5V power-supply operation. the MAX504 can also be operated with ±5V supplies. The MAX515 draws only 140µA, and the MAX504 (with internal reference) draws only 260µA. The MAX515 comes in 8-pin DIP and SO packages, while the MAX504 comes in 14-pin DIP and SO packages. Both parts have been trimmed for offset voltage, gain, and linearity, so no further adjustment is necessary.
The MAX515’s buffer is fixed at a gain of 2. The MAX504’s internal op amp may be configured for a gain of 1 or 2, as well as for unipolar or bipolar output voltages. The MAX504 can also be used as a four-quadrant multiplier without external resistors or op amps. For parallel data inputs, see the MAX503 data sheet. For a hardware and software compatible 12-bit upgrade, refer to the MAX531/MAX538/MAX539 data sheet.
Applications:
» Audio Systems
» Battery-Operated/Remote Industrial Controls
» Battery-Powered Test Instruments
» Digital Gain and Offset Control
» Machine- and Motion-Control Devices


Download free datasheet: MAX515 5V, Low-Power, Voltage-Output, Serial, 10-Bit DACs

source : http://www.freedatasheetdownload.com

Transistors

A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. The transistor is the fundamental building block of the circuitry that governs the operation of computers, cellular phones, and all other modern electronics.

Because of its fast response and accuracy, the transistor may be used in a wide variety of digital and analog functions, including amplification, switching, voltage regulation, signal modulation, and oscillators. Transistors may be packaged individually or as part of an integrated circuit, which may hold a billion or more transistors in a very small area.
Introduction
Modern transistors are divided into two main categories: bipolar junction transistors (BJTs) and field effect transistors (FETs). Application of current in BJTs and voltage in FETs between the input and common terminals increases the conductivity between the common and output terminals, thereby controlling current flow between them. The transistor characteristics depend on their type. See Transistor models.
The term "transistor" originally referred to the point contact type, but these only saw very limited commercial application, being replaced by the much more practical bipolar junction types in the early 1950s. Today's most widely used schematic symbol, like the term "transistor", originally referred to these long-obsolete devices.[1] For a short time in the early 1960s, some manufacturers and publishers of electronics magazines started to replace these with symbols that more accurately depicted the different construction of the bipolar transistor, but this idea was soon abandoned.
Types
- Bipolar junction transistor
- Field-effect transistor
- Heterojunction Bipolar Transistor
- Tetrode transistor
- Pentode transistor
- Spacistor
- Surface barrier transistor
- Micro alloy transistor
- Micro alloy diffused transistor
- Drift-field transistor
- Unijunction transistors
- Darlington transistors
- Insulated gate bipolar transistors (IGBTs)
Usage
- Switches
- Amplifiers
- Computers

LiteSpeed Load Balancer

LiteSpeed Load Balancer (LSLB) is a high-performance, content-aware, session-aware HTTP application load balancer. It can forward requests based on request content as well as session stickiness preference. LiteSpeed Load Balancer can help scale your application beyond one server deployment, as well as improve the reliability of your service in case of hardware failures.

We offer 15-day risk free trials and a 30-day money back guarantee.

Features

HTTP/1.1, HTTP/1.0 backward compatible

Supports HTTP, LiteSpeed SAPI, FastCGI and AJPv13 back ends

Load balance algorithms: round-robin, least load, least session

Session affinity with fail-over

Directing request based on domain names, request URL, Cookie, SSL Session, etc.

Content aware: route request based on request content

Dynamic response compression/decompression (gzip)

Gzip compression with backend HTTP Server

Automatic HTTP protocol upgrade/downgrade to maintain persistent connection with backend servers

Massive shared hosting: load balance to millions of websites

URL rewrite

SSL acceleration

Geotargeting support

IPv6 support

Anti-(D)DoS attacks capability

Request filtering (HTTP firewall), filter attacking requests based on request content

Chroot for enhanced security

Backend server health monitoring

Web administration console

Online upgrade to keep your server up-to-date

Security

LiteSpeed load balancer is designed to be a secure load balancer. With chroot jail, IP level bandwidth throttling, connection accounting, strict HTTP request checking, and URL context filtering, DoS effects are minimized and backend cluster is properly fenced away from the HTTP request layer reducing vulnerability.

High performance Secure HTTP (HTTPS): supports SSLv2, SSLv3 and TLSv1

IP level throttling (Bandwidth and Request Rate)

Comprehensive IP level connection accounting

Hotlink protection

Strict HTTP request checking

External application firewall for dynamic content

Chroot whole server process

Reliability

Zero downtime maintanance (include reconfiguration, software upgrade)

Watch dog and Instant recovery maximizes up-time

Graceful shutdown, all requests in process will be completed.

Runs completely in the user space, OS reliability is not affected

The following section provides a brief overview of the above security features. Access Control: Server, virtual host and directory (context) level access control which can allow or block traffic from specific IP/sub-networks. IP Level Throttling Limits network bandwidth to and from a single IP address regardless of the number of connections. IP Level Connection Accounting Limits the number of concurrent connections from a single IP address. It is controlled by the Connection Soft Limit, Connection Hard Limit, Grace Period, and Banned Period values. Strict Request Checking Every HTTP request is strictly checked by LiteSpeed load balancer:

Request size is limited by the Max Request URL Length, Max Request Header Length, and Max Request Body Length values. Strict Static File Checking LiteSpeed web server will serve a static file only if the following conditions are satisfied:

"/.ht*" and "/.svn*" are not allowed in a decoded URL, this will deny accessing some important hidden files and directories.

the file permission must contain configured required permission bits.

the file permission must not contain any configured restricted permission bits.

The file is not in the Access Denied Directory list

does not contain symbolic links if symbolic linking is not allowed.

LiteSpeed load balancer does not index a directory by listing its files.

LiteSpeed load balancer can pipeline requests and control the concurrency level of external applications to prevent over consumption of system resources. It only forwards completed requests to external applications and caches the response. Thus external applications will be immediately available to process the next request without waiting for the response to be completely received by the client. In this way, the server can utilize fewer instances of external applications to serve more concurrent requests and will achieve higher performance and scalability. LiteSpeed load balancer uses its own virtual memory to cache the request and response body to minimize the usage of system memory without sacrificing performance.

Chroot Jail

LiteSpeed load balancer can run in a chroot environment also known as a chroot jail with an automatic initial chroot environment setup. In a chrooted environment, the load balancer and its children processes cannot access the file system outside of the chroot jail. This protects the system from attacks caused by malicious code.

3D INTEGRATED CIRCUIT

GLOBAL Semiconductor Alliance says it will increase awareness and visibility worldwide for its 3D integrated circuit initiative.

The GSA has retained semiconductor industry veteran, Herb Reiter to lead the 3D IC initiative. It has also formed relationships with IMEC, ITRI, SEMI, SEMATECH and Si2 to help direct and participate in this effort.

The GSA says it has presented papers and gained awareness for 3D IC at multiple global events, such as DATE 2010 in Dresden, DAC, SemiCon West and the GSA Emerging Opportunities Expo and Conference.

According to the Alliance, the 3D IC initiative will be a major feature of its second annual Memory Conference on 31 March 2011 in San Jose. The theme for the 2011 conference will be “Memory and Logic Integration and the Benefits of 3D IC Technology”.

The Alliance claims 3D IC is a way forward in the face of the challenges of rapidly increasing power dissipation of ICs and systems.

The wireless industry is also pushing for 3D IC stacks to meet the power and space constraints in Mobile Internet Devices, and the technology is expected to help meet next generation bandwidth and performance requirements.

History of the Integrated Circuit aka Microchip

D you know Integrated Circuit . What we didn't realize then was that the integrated circuit would reduce the cost of electronic functions by a factor of a million to one, nothing had ever done that for anything before" - Jack Kilby

The Integrated Circuit

It seems that the integrated circuit was destined to be invented. Two separate inventors, unaware of each other's activities, invented almost identical integrated circuits or ICs at nearly the same time.Patents for the Integrated Circuit

In 1959 both parties applied for patents. Jack Kilby and Texas Instruments received U.S. patent #3,138,743 for miniaturized electronic circuits. Robert Noyce and the Fairchild Semiconductor Corporation received U.S. patent #2,981,877 for a silicon based integrated circuit. The two companies wisely decided to cross license their technologies after several years of legal battles, creating a global market now worth about $1 trillion a year.

Commercial Release

In 1961 the first commercially available integrated circuits came from the Fairchild Semiconductor Corporation. All computers then started to be made using chips instead of the individual transistors and their accompanying parts. Texas Instruments first used the chips in Air Force computers and the Minuteman Missile in 1962. They later used the chips to produce the first electronic portable calculators. The original IC had only one transistor, three resistors and one capacitor and was the size of an adult's pinkie finger. Today an IC smaller than a penny can hold 125 million transistors.

Jack Kilby holds patents on over sixty inventions and is also well known as the inventor of the portable calculator (1967). In 1970 he was awarded the National Medal of Science. Robert Noyce, with sixteen patents to his name, founded Intel, the company responsible for the invention of the microprocessor, in 1968. But for both men the invention of the integrated circuit stands historically as one of the most important innovations of mankind. Almost all modern products use chip technology.