electrical circuit, ouh pathetic

I've just got lab work on digital egineering this semester...
it's however more fun than staying in class analyzing the digital circuit on the white board. I cu'd find out what those gates are really like in their physical appearance. I can make my own shift register, the counter, etc. And also, I can realize that the real circuit is somehow much more complicated than those on the white board in the class room.

Last week we've got the final project, and that was the first time for me to make a real simple electrical circuit for some kind of tools in digital. this is actually free week for my college, but since i must finish the final project before the semester ends, i decided not to go home.
I really feel the hardest parts of making circuits...Ouh... i can imagine how those designers are really busy with what they work on.

Its the circuit!!! after I find some kinda ideas on my final project I have to make it real! how this shit on the sheet can really pop up onto your desk in the lab, in fact that is the main trouble.
I make the simulation, after this work well as we want the next job is to make all the ICs used are the same type, be it CMOS or TTL or whatever, as long as they come at the same type. because the different type of IC will take different level of voltage to activate it self, so the more kind of the used ICs the more complicated the circuit wu'd be.!

then, I gotta make the circuit or draw the circuit on PCB. But before I cu'd draw the route I gotta find out if the ICs available on market, then I just found out the next problem!!! because some components required on my project can't be found on market I gotta replace the component with another one whose function on circuit is the same, it means I gotta redesign my circuit. And in fact I have redesigned my circuit several times becuze of this shit! OOOUUH.....

Ouh... sometimes your creativity is even limited by the market... the demands may determine what u gonna make in electronics work.... what would U say beside " U re just less creative"?

Aerospace Electronic Acronyms and Definitions

The terms listed below are those which are usually used in electronic eng. especially Aerospace Electronic; completely taken from: The Clemson University Vehicular Electronics Laboratory(http://www.cvel.clemson.edu/aero/tutorials/definitions.html) with little changes. I hope you could find the terms you are looking for,

ABS - Antilock Brake System

A mechatronic system that senses when the wheels are skidding during braking and pulses the brake pressure to allow the wheels to turn just enough to maintain control of the car.

AF - Antenna Factor

The ratio of the received field strength to the voltage appearing at the terminals of a receiving antenna OR the ratio of the transmitted field strength at a specified distance to the voltage applied to the terminals of a transmitting antenna. Antenna factors are functions of position and frequency.

ALSE - Absorber-Lined Shielded Environment

An EMC test environment consisting of a shielded room with material on the walls and ceiling that absorbs electromagnetic radiation.

ARINC - (originally) Aeronautical Radio, Inc

Now officially called ARINC Incorporated, this company is an aerospace industry contractor. Among other things, they develop and maintain a variety of aerospace electronics standards.

ASIC - Application Specific Integrated Circuit

An integrated circuit that designed and built for a specific application, usually in a specific product or product line.

BCI - Bulk Current Injection

A type of EMC test where common-mode currents are induced on the power and communications cables of the device under test.

CAN - Controller Area Network

A common network protocol used in automotive applications. CAN buses employing twisted wire pairs were specifically designed to be robust in electromagnetically noisy environments. The applications of CAN bus in automobiles include window and seat operation (low speed), engine management (high speed), brake control (high speed) and many other systems. CAN buses can also be found in other embedded control applications such as factory automation, building automation, and aerospace systems.

CENELEC - European Committee for Electrotechnical Standardization

CENELEC’s mission is to prepare voluntary electrotechnical standards (including EMC standards) that help develop the Single European Market/European Economic Area for electrical and electronic goods and services removing barriers to trade, creating new markets and cutting compliance costs.

CISPR - Committee on Special International Committee on Radio Interference

CISPR is an international organization concerned with developing standards for detecting, measuring and comparing electromagnetic interference in electric devices.

CMOS - Complementary Metal Oxide Semiconductor

A semiconductor fabrication technology characterized by relatively low quiescent power consumption capable of very high speed switching. Most digital semiconductor devices in an automobile including all of the microprocessors and microcontrollers are CMOS devices.

CPU - Central Processing Unit

The part of a microprocessor or microcontroller that does the arithmetic computations.

DSP - Digital Signal Processor

A microprocessor optimized to digitize analog signals and process the signal information.

ECM - Engine Control Module

An electronic module that controls the operation of an internal combustion engine including the throttle, fuel injection and spark timing.

ECU - Electronic Control Unit

The device in an automotive electronic system that controls the operation of the system. A typical automobile will have dozens of ECUs.

EEPROM - Electrically Erasable Programmable Read only Memory

Electronic memory devices that keep information stored even without power, but can be erased and reprogrammed electrically.

EMC - Electromagnetic Compatibility

The ability of an electronic device or system to function without error in its intended electromagnetic environment.

EMD - Electromagnetic Disturbance

Any electromagnetic phenomenon that may interfere with the normal function of an electronic device.

EMI - Electromagnetic Interference

The disruption of an electronic device or system due to an electromagnetic phenomena.

EMP - Electromagnetic Pulse

Strong electromagnetic transients such as those created by lightning or nuclear blasts.

ESD - Electrostatic Discharge

A sudden surge in current usually due to an electric spark or dielectric breakdown characterized by risetimes less than one nanosecond and total pulse widths on the order of microseconds.

EUROCAE - European Organisation for Civil Aviation Equipment

EUROCAE is a non-profit organization whose members are aviation stakeholders including Manufacturers (aircraft, airborne equipment, ATM systems and ground equipment), Services Providers, National and International Aviation Authorities and Users (Airlines, Airports, operators) from Europe and elsewhere.

EUT - Equipment Under Test

The device being evaluated by an EMC test (see also DUT).

EW - Electronic Warfare

A battle strategy that involves disabling an enemy's electronic communications or controls, usually by generating an interfering signal or electromagnetic pulse with sufficient energy to damage electronic circuits.

FADEC - Fully Automatic Digital Engine Controller

The computer that controls all aspects of an aircraft engine's performance (piston or jet engines).

FFT - Fast Fourier Transform

An algorithm for quickly calculating the frequency-domain representation of a time-domain signal.

HEMP - High-altitude Electromagnetic Pulse

Strong electromagnetic transient field that is created by a nuclear device discharged high in the atmosphere (also sometimes referred to as NEMP or Nuclear Electromagnetic Pulse).

ICM - Ignition Control Module

The electronic control for the ignition system.

IEC - International Electrotechnical Commission

The IEC is an international organization that prepares and publishes international standards (including many EMC standards) for all electrical, electronic and related technologies.

IEEE - Institute of Electrical and Electronics Engineers

IEEE is the world's leading professional association for the advancement of technology. The IEEE name was originally an acronym for the Institute of Electrical and Electronics Engineers, Inc. Today, the organization's scope of interest has expanded into so many related fields, that it is simply referred to by the letters I-E-E-E (pronounced Eye-triple-E).

ISO - International Organization for Standardization

ISO is a network of the national standards institutes of 157 countries, one member per country, with a Central Secretariat in Geneva, Switzerland, that coordinates the system.

LED - Light Emitting Diode

A light source of growing importance to the automobile industry. LEDs are more efficient and more durable than incandescent light sources.

LISN - Line Impedance Stabilization Network

A passive, two-port network that is placed between the power supply and the power input of equipment under test. It passes power to the equipment while providing a known high-frequency impedance. Test equipment for measuring the voltage on the power supply lines is connected directly to the LISN.

LTCC - Low Temperature Cold Fired Ceramic

A microelectronics packaging technology particularly well suited for wireless and high-frequency applications.

MEMS - MicroElectro-Mechanical System

Tiny electro-mechanical devices etched in silicon. MEMS technology is used to make a variety of sensors used in automobiles. MEMS sensors are small, rugged and low-cost in high volumes.

MOST - Media Oriented Systems Transport

A network protocol employing optical fiber used in entertainment applications.

NASA - National Aeronautics and Space Administration

NASA is the agency that oversees the U.S. space program.

NEMP - Nuclear Electromagnetic Pulse

Strong electromagnetic transient field that is created by a nuclear device discharged high in the atmosphere (more commonly referred to as HEMP or high-altitude Electromagnetic Pulse).

OATS - Open Area Test Site

An EMC test environment free of reflecting objects except a ground plane.

PCB - Printed Circuit Board

A board consisting of layers of copper connections separated by a fiberglass resin or ceramic dielectric. Electronic components are usually mounted on the top and/or bottom of the board.

PWM - Pulse Width Modulation

A technique for regulating the amount of energy conveyed in a digital (on/off) signal by regulating the width of pulses that are transmitted at a given frequency.

RADAR - RAdiation Detecting and Ranging

A technology that relies on the reflection of electromagnetic signals to determine the distance and velocity of far away objects.

RAM - Random Access Memory

Electronic digital memory that can be accessed by providing a specific address for the information desired.

RCS - Radar Cross Section

A measure of the strength of a radar signal reflection from an object. RCS is an indication of the range at which an object can be detected by radar.

ROM - Read Only Memory

Electronic digital memory that can be read, but not rewritten or erased.

RF - Radio Frequency

A frequency at which electromagnetic radiation of energy is useful for communications. Radio frequencies are designated as very low: 3 kHz to 30 kHz, low: 30 to 300 kHz, medium: 300 to 3,000 kHz, high: 3 to 30 MHz, very high: 30 to 300 MHz, ultrahigh: 300 to 3,000 MHz, super high: 3 to 30 GHz, and extremely high: 30 to 300 GHz.

RTCA - Radio Technical Commission for Aeronautics

RTCA, Inc. is a private, not-for-profit corporation that develops consensus-based recommendations regarding communications, navigation, surveillance, and air traffic management (CNS/ATM) system issues.

TEM - Transverse ElectroMagnetic

An electromagnetic plane wave where the electric and magnetic fields are perpendicular to each other everywhere and both fields are perpendicular to the direction of propagation. TEM cells are often used to generate TEM waves for radiated immunity (RI) testing.

SAE - Society of Automotive Engineers

A professional society for automotive and aerospace engineers. Formerly, SAE was an acronym for the Society of Automotive Engineers. Now, the society is officially called SAE International.

SMD - Surface Mount Device

An electronic component with no leads that is glued to a printed circuit board, then wave-soldered. Also called SMT devices (for Surface Mount Technology).

UAV - Unmanned (or Uninhabited) Arial Vehicle

An aircraft that is controlled remotely (or by program) without any human occupants.

XTALK - Crosstalk

A measure of the electromagnetic coupling from one circuit to another.

Space Shuttle Main Engines, small in size big in power

This engine is somehow special one, because this high fuel consumption engine has small size as well as weight but really vast power. The article below is what I got from nasa.gov, coopsjokes.com, as well as other sources.

The engine of a space shuttle is actually consisting of three main engines, which are the two solid rocket boosters and the space shuttle engine itself. The space shuttle engine also consists of three main engines, which each of them is 14 feet long, 7.5 feet wide at mouth of nozzle.

The duration of the Shuttle’s powered flight is only 8.5 minutes, for which the main engines continue to operate after launch.

After the two boosters are jettisoned, the main engines provide thrust which accelerates the shuttle from 4,828 Km/h (3,000 mph) to over 27,358 Km/h (17,000 mph) in just six minutes to reach the orbit. Those three engines create combined maximum thrust of more than 1.2 million pounds.

During the accelerating, the main engines burn a half-million gallons of liquid propellant provided by the large external fuel tank, large tank between two boosters. The propellant mixture are 6 parts liquid oxygen to 1 part liquid hydrogen (by weight). This ratio of weight is used to produce thrust of 179,097 kilograms at the sea level and 213,188 kilograms at vacuum. For you know, the liquid hydrogen is the 2nd coldest liquid on Earth, which is minus 423 degrees Fahrenheit (-252.8 degrees Celsius).

From the combustion, engine’s exhaust is primarily water vapor as the hydrogen and oxygen combine. Those engines consume liquid fuel at a rate that would drain average family pool in less than 25 seconds and generating over 37 million horsepower, While, the boosters burn about 5 tons of propellant per second.

The main engines develop thrust by using high-energy propellants in a staged combustion cycle. The propellants are partially combusted in dual pre-burners to produce high-pressure hot gas to drive the turbopumps. The combustion is completed in the main combustion chamber. Temperatures in the main engine combustion chamber can reach 6,000 degrees Fahrenheit, which is higher than metal boiling point.

The engines can be throttled over a thrust range of 65 percent to 109 percent, which provides for a high thrust level during the liftoff and the initial ascent phase but allows thrust to be produced to limit acceleration to 3 g’s during the final scent phase. The engines are gimbaled to provide pitch, yaw and roll control during the ascent.

Afterburner

Sebuah afterburner atau reheat adalah sebuah komponen tambahan yang ditambahkan pada beberapa mesin jet, terutama pesawat-pesawat supersonik di militer. tujuannya adalah untuk menyediakan peningkatan dorongan singkat, baik untuk terbang dengan kecepatan supersonik atau takeoff. Pada pesawat militer dorongan extra juga diperlukan pada saat combat atau saat tempur di udara. kondisi ini diperoleh dengan menginjeksikan fuel tambahan ke dalam pipa hilir jet dari(setelah) turbin. Bahan bakar ini disulut dengan gas panas dan menambah daya dorong pada mesin secara besar-besaran. Keuntungan dari afterburning tentu saja adalah tambahan thrust yang sangat signifikan, kerugiannya adalah konsumsi fuel yang sangat besar dan inefisiensi(ke-tidakefisien-an), meskipun hal ini masih bisa diterima dalam periode yg singkat selama afterburning dilakukan. Mesin jet dikatakan beroperasi "basah" ketika menggunakan afterburner dan "kering" ketika tanpa afterburner.

DESIGN

Sebuah afterburner mesin jet adalah seksi buangan (bagian exhaust) yang telah dikembangkan berisi injector-injector bahan bakar ekstra, dan karena mesin jet bagian upstream (sebelum turbin) akan menggunakan sedikit oksigen yg dihisapnya, afterburner adalah (pada bagian paling sederhananya), sejenis ramjet. Ketika afterburner dinyalakan, fuel is injected, yg telah siap dibakar, bertepatan dengan temperatur yg relative tinggi dari gas yg masuk. Pembakaran yg dihasilkan akan meningkatkan temperatur dari afterburner exit (nozzle entry, keluaran dari afterburner adalah masukan untuk nozzle) secara signifikan, menghasilkan peningkatan engine net thrust yang sangat tajam. Selain adanya peningkatan stagnasi suhu pada 'exit' afterburner, juga ada sebuah peningkatan pada aliran massa pada 'nozzle'(i.e. aliran massa entry afterburner ditambah dengan aliran bahan bakar afterburner yang effektif), tapi juga muncul penurunan pada tekanan stagnasi pada 'exit afterburner' (disebabkan oleh rugi-rugi mendasar akibat dari pemanasan, friksi atau gesekan dan juga rugi-rugi akibat turbulensi).

Peningkatan yang dihasilkan pada aliran volum dari exit afterburner ditampung oleh peningkatan luas throat dari 'propulsion nozzle'. Sebaliknya, mesin turbo bagian atas (upstream turbomachinery) dinyalakan ulang(mungkin menjadi penyebab 'compressor stall' atau hentakan kipas pada sebuah aplikasi turbofan).

Pada orde pertama, perbandingan kotor dari 'thrust' (afterburning/dry) adalah berbanding lurus dengan akar dari rasio temperatur stagnasi malalui afterburner (yaitu, exit/entry).

Pembatasan
Dikarenakan tingkat konsumsi fuel-nya yang tinggi, afteburner tentu tidak digunakan dalam waktu yang 'lama'(extended period), sebuah pengecualian adalah mesin Pratty & Whitney J58 yang digunakan oleh pesawat SR-71 Blackbird. Jadi, afterburner hanya digunakan pada saat dimana kebutuhan thrust sebesar mungkin menjadi sangat penting. Saat penting itu termasuk takeoff dari runway pendek(seperti pada pesawat carrier) dan situasi pertarungan udara.

Efisiensi

Karena gas buangan (exhaust gas) telah mereduksi oksigen pada pembakaran sebelumnya, dan karena bahan bakar tidak dibakar pada lajur udara bertekanan tinggi(highly compressed air column), maka secara umum afterburner tidak efisien dibandingkan dengan combustor utama. Efisiensi afterburner juga menurun secara signifikan jika, seperti pada umumnya, tekanan pada taipipe menururn karena bertambahnya ketnggian pesawat.

Meskipun demkian, sebagai contoh-pengecualian SR-71 mempunyai efisiensi yang lumayan pada ketinggian (high altitude) dengan mode afterburner(wet) untuk memenuhi kecepatannya yaitu mach 3.2 dan tentusaja tekanan tinggi karena ram effect.

Afterburner juga menghasilkan thrust yang sangat menyolok dan juga sangat besar, nyala api yang sangat 'mempesona' di belakang mesin. Api buangan ini bisa menunjukkan 'shock-diamond', yang disebabkan oleh 'gelombang kejut' yang timbul karena perbedaan tipis antara tekanan atmosfer sekitar pesawat dengan tekanan exhaust atau lubang buang. Ketidakseimbangan itu menimbulkan osilasi pada diameter semburan jet melampaui jarak yang jauh dan mengakibatkan ikatan yang tampak dimana tekanan dan suhu mencapai puncaknya.

Info lebih lanjut, Wikipedia.