Saturday, September 25, 2010

The silicon chips

Most people will have heard of the " silicon chips".There are many such  devices,but the words are usually taken to mean a microprocessor.The heart of any computer is something called a central processing unit (CPU),the microprocessor (MPU) is simply a CPU which has been considerably reduced in size using modern integrated circuit technology. This 'computer on a piece of silicon' is so small,it's probably no bigger than the nail on yours little finger.How the microprocessor function and now how it is 'programmed' is what we are about to investigate.Machine code programming will be discussed-this is the code that the microprocessor actually 'understands'.
Some home computer users program in 'BASIC' but this is only for the users convenience. An interpreter inside the computer converts the basic program into machine code.This slows down program execution hundreds of times and increases the cost of the system.Hence,using machine code programming speeds up operation dramatically and uses less 'firmware'.


Friday, September 24, 2010

Atmel 89S and AVR Programmer(STK200)

A kit for this activity is accessible from RSH Electronics.

Download PDF adaptation of this folio

The ambit starts timing back switched on. The blooming LED lights to appearance that timing is in progress. Back the time aeon is over the blooming LED turns off, the red LED turns on and the bleeper sounds.
Adjustable 1-10 Minute Timer Project
The time aeon is set by adjusting the capricious resistor. It can be adapted from 1 to 10 account (approximately) with the genitalia apparent in the diagram. You can mark the times on a calibration fatigued on the box.

Please agenda that the ambit of time periods is alone approximate. With absolute apparatus the best time aeon should be 4½ minutes, but this is about continued to about 10 account because the 220µF timing capacitor boring leaks charge. This is a botheration with all electrolytic capacitors, but some aperture added than others. In accession the absolute amount of electrolytic capacitors can alter by as abundant as ±30% of their rated value.

This activity uses a power-on triggered 555 monostable circuit.

Parts Required

resistors: 470, 33k, 100k

variable resistor: 1M

capacitors: 0.1µF, 220µF 16V radial

LEDs: red, green

bleeper 9-12V

555 timer IC

8-pin DIL atrium for IC

on/off switch

battery blow for 9V PP3

stripboard 10 rows × 22 holes

Saturday, September 4, 2010

Schematic amplifier for head phone op-50

 Schematic amplifier

Performance of the circuit: (Vout = 6Vrms, R1=4k©)

T.H.D @ 100HZ = 0.0025%
@ 1KHZ = 0.003%
@ 10KHZ = 0.011%
Relationship sign noise p5; 80dB
answer = ±0.4dB from 10Hz to 20Khz

Band with = -3dB @ 56KHz

Friday, September 3, 2010

Liquid PCB different from other PCB programs

Liquid PCB was designed from the point of view of the user. I think that the computer should take as much work from the user as possible, while still giving them the freedom to produce an excellent design. It should be possible to navigate the interface using as few mouse clicks as possible.
Liquid PCB actually uses the immense power of your computer’s CPU and GPU to help you. Rather than sitting idle, waiting for a mouse click, Liquid PCB constantly enforces your design rules, and optimises your track, component and via placement. You are not confined to straight tracks at 45° angles, nor to components at 90° angles. Drag tracks wherever you want, even squeeze them into small gaps, and let Liquid PCB sort it out.

Liquid PCB also has a user interface which has been designed specifically to reduce the amount of clicking and fiddling you have to do. Many functions can be accessed with only one, or sometimes zero clicks.

LiquidPCB is aware of the flow of information into and out of your PCB project. For example, a typical PCB will use a netlist, generated from a schematic capture package. It may also use a 3D model file from a CAD package. These are the inputs Rather than simply importing these files into LiquidPCB, you create a dependency on them. So, if any of those files are modified, LiquidPCB will automatically inform you, and give you the option to update.
Likewise, Output files generated from the PCB (Gerber, engineering drawings, BOMs, etc.) will be automatically updated when the PCB changes.

Thursday, September 2, 2010

Schematic Long Range FM transmitter Circuit

The power output of most of these circuits are very low because no power amplifier stages were incorporated.The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts. With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, this transmitter can provide reasonably good signal strength up to a distance of about 2 kilometers.

The circuit built around transistor T1 (BF494) is a basic low-power variable-frequency VHF oscillator. A varicap diode circuit is included to change the frequency of the transmitter and to provide frequency modulation by audio signals. The output of the oscillator is about 50 milliwatts. Transistor T2 (2N3866) forms a VHF-class A power amplifier. It boosts the oscillator signals’ power four to five times. Thus, 200-250 milliwatts of power is generated at the collector of transistor T2.
For better results, assemble the circuit on a good-quality glass epoxy board and house the transmitter inside an aluminum case. Shield the oscillator stage using an aluminum sheet.

Coil winding details are given below:L1 - 4 turns of 20 SWG wire close wound over 8mm diameter plastic former.L2 - 2 turns of 24 SWG wire near top end of L1.(Note: No core (i.e. air core) is used for the above coils)L3 - 7 turns of 24 SWG wire close wound with 4mm diameter air core.L4 - 7 turns of 24 SWG wire-wound on a ferrite bead (as choke)Potentiometer VR1 is used to vary the fundamental frequency whereas potentiometer VR2 is used as power control. For hum-free operation, operate the transmitter on a 12V rechargeable battery pack of 10 x 1.2-volt Ni-Cd cells. Transistor T2 must be mounted on a heat sink. Do not switch on the transmitter without a matching antenna. Adjust both trimmers (VC1 and VC2) for maximum transmission power. Adjust potentiometer VR1 to set the fundamental frequency near 100 MHz.This transmitter should only be used for educational purposes.

Wednesday, September 1, 2010

Birth of an Industry Microcontroller

Significant technological breakthroughs usually result from seeking a solution to a problem and they add to a body of existing knowledge. The development of solid-state electronic followed this pattern building on the limitations of early computers and leading to this development of the transistors in 1947.

One problem occurred prior to the 1890 U.S. census. It was predicted that the 1890 census would take 10 years to condense and correlate by manual tabulation. This length of time was unaccepted and led the U.S. Census Bureau to sponsor a contest for a new method of process mechanical tabulating machine that completed the census data crunching in an amazing six weeks. His Machine was a mechanical system driven by an electrical motor that introduced the punch card.Hollerith went on to form the Tabulating Machine Company,Which eventually evolved into the International Business Machine Corporation(IBM).

This tabulating machine was one of the earliest computers, A machine that was designed to perform automatic calculations on data. The technology of computer continued to progress in the 1930s with the development of computers using electromechanical switch. During World War II, intelligent and fast machine to crack secret codes were developed. One result of these efforts was the world's first electronic computer, the Electronic Numeric Integrator and Calculation or ENIAC for short. The ENIAC was first demonstrated ata the Moore School of Engineering in Pennsylvania in 194.

ENIAC hardly fits the modern picture of a computer. It occupied some 3000 ft2, weighed 50 tons,generated large quantities of heat, required the service of a small power station and cost $400,000 in 1940 dollars.