TEKNOLOGI LISTRIK DALAM RUMAH TANGGA

Listrik adalah teknologi yang sangat penting dalam kehidupan kita. Sekarang menjadi sesuatu yang kita butuhkan dalam kehidupan. Jika berhenti sedetik saja, banyak orang akan merasa menderita. Meski sebenarnya, kita tidak harus seperti itu.

Meski listrik itu sangat banyak manfaatnya dan kita butuhkan, tetapi kalau kita tidak hati-hati akan membuat petaka. Banyak terjadi kesalahan, kebakaran yang diakibatkan karena penggunaan listrik di dalam rumah. Berangkat dari pemasangan instalasi listrik yang asal-asalan, sambungan kurang kuat, penggunaan daya berlebihan untuk satu titik terminal. Penggunaan kabel yang terlalu kecil untuk ukuran daya yang diperlukan. Dan kesalahan-kesalahan yang lainnya.

Untuk itulah kita harus menjaga, mengamati dan merawatnya secara berkala. Agar listrik itu tidak menjadi petaka bagi kita. Bukan hanya kita, tetapi juga orang lain di sekitar kita, keluarga kita, teman kita dan para tetangga kita. 

Jika kita belum tahu, maka kita harus berusaha mencari tahu tentang listrik. Yang paling mudah adalah bertanya kepada para ahlinya. Jika kita sudah tahu, maka selanjutnya kita memberitahu orang-orang di sekitar kita. 

Kenalilah listrik dengan baik, karena ia ada di sekitar kita. Pahamilah listrik dengan baik, agar ia berguna bagi kehidupan kita. Dan bukan menghanguskan apa-apa yang telah kita miliki. Kita harus menjaga keamanan listrik setiap saat, hanya untuk menghindari satu masa kecelakaan---kebakaran.

Apalagi sekarang sudah jamannya internet. Setiap orang dengan mudah mengakses internet. Kita tinggal mau atau tidak untuk belajar listrik.

Berikut saya sertakan beberapa link yang membahasa tentang teknologi listrik

TEKNOLOGI LISTRIK

LISTRIK, TAK KENAL MAKA TAK HATI-HATI

LISTRIK, TAK KENAL MAKA TAK HATI-HATI 2

KESETRUM LISTRIK

WASPADA INSTALASI LISTRIK JIKA RUMAH TERGENANG

HATI-HATI MENGGUNAKAH KABEL ROL

PERCIKAN API LISTRIK DI RUMAH

FORUM INSTALASI LISTRIK RUMAH

PENGUJIAN TAHANAN ISOLASI

APA YANG DIMAKSUD MEGGER TESTER DAN APA FUNGSINYA?

PENGUJIAN INSTALASI KABEL LISTRIK –MEGGER TESTER

SISTEM PENTANAHAN INSTALASI LISTRIK

GROUNDING INSTALASI LISTRIK RUMAH

GROUNDING INSTALASI LISTRIK KAPAL LAUT

LISTRIK 380V/220V 3PHASE

SISTEM LISTRIK 3 PHASE

MOTOR LISTRIK

PENGAMAN MOTOR LISTRIK

APA BENAR LISTRIK 230V TERBAIK?

AWAL PERKEMBANGAN INDUSTRI KOMPUTER DI JEPANG

Pemerintah Jepang mendukung usaha-usaha bisnis perusahaan teknologi computer dengan dana bantuan yang besar. Dalam tahun 1980 MITI (Ministry of International, Trade and Industry-Kementrian Internasional, Perdagangan dan Industri) Jepang mengumumkan  Proyek Superkomputer yang bertujuan untuk mengembangkan mesin ultracepat menjelang tahun 1989 dengan kemampuan 10 GHz. Pada tahun 1981, enam pembuat computer terkemuka di Jepang, yaitu Fujitsu, Hitachi, Mitsubushi,NEC, Oki Electric dan Thosiba membentuk Asosiasi Penelitian Komputer Ilmiah untuk bekerja bersama dalam proyek tersebut. Proyek tersebut menjalankan penelitian gabungan di laboratotium perusahaan-perusahaan tersebut. Proyek Sembilan tahun ini didanai USD 150Juta, yang setengahnya dari MITI dan setengahnya lagi dari enam perusahaan tersebut.

Kasus industri di Jepang, suatu komponen dalam negeri penting dari kebijakan pengalihan teknologi Jepang ke dalam adalah penyebaran dari teknologi bersumber asing oleh MITI. MITI memakai perizinan teknologi asing untuk ‘meratakan lapangan permainan’ diantara perusahaan-perusahaan dalam negeri dan memastikan persaingan dalam negeri yang sengit dalam teknologi ini. Dari tahun 1961-1981, pemerintah Jepang telah menanamkan kira-kira USD 6 Milyar dalam industri computer untuk litbang, pralatan baru dan modal kerja. Peralatan dan pengembangan yang disubsidi terikat pada kinerja itu. Jika sebuah perusahaan gagal untuk mengkomersialisasikan hasil-hasil proyek atau menjadi tidak bersaing, maka tidak akan diikutsertakan pada tahap berikutnya. Dan pemerintah mendorong perusahaan untuk melakukan penelitian yang beresiko tinggi yang biasanya akan dihindari misalnya proyek VLSI. Dengan demikian pemerintah Jepang membantu perusahaan maju dalam bidang ini, tetapi membiarkan mereka untuk bersaing dalam mengkomersialkan litbang dan masuk pasaran. Untuk setiap perusahaan ada waktu bersaing dan ada waktu untuk kerja sama. Itu pelajaran yang patut disimak.

SATELLITE COMMUNICATIONS

Introduction. For many years, the notion of satellite communications was a fantasy produced by fertile mind of Arthur C Clarke; a brilliant idea but rather impractical. As with so many creative ideas, technology eventually caught up and now satellites are commonplace. For the communication engineer, however, they represent challenging and stimulating field of work. Within satellite communication system we find the whole gamut of technologies operating in a strange and demanding as little energy to run as possible, the system must be capable of withstanding the arduous journey from earth to orbit. Consequently a careful balance must be struck between the mechanical, structural, electronic, electrical and electromagnetic engineering requirements of the system. Satellite communications provide opportunities, and pose problems, in communication methods. Their large area of access (footprint) allows a single transmission to cover an enormous number of receivers, thus allowing broadcast signals to be transmitted simultaneously to large number of people. However, this feature itself creates difficulties; partly political and partly economic. National boundaries are no barrier whatsoever, and the charging mechanism required to allow the satellite operator to recover the cost of development and provide continuous support requires a novel solution. Satellites can travel in variety orbits, basically elliptical in shape. A geostationary satellite system which orbit is fixed and essentially circular. It maintains a fixed position relative to points on earth, and this allows a cheap receiving antenna to be set up once and then fixed position.  

The disc will be as small as possible and the amplifier as cheap as possible, consistent with obtaining an adequate signal for most of the year. Outage will be high, compare with that for a better quality receiver, but must still be at reasonable level. The preoccupation in satellite link design is the power budget; how much power can be obtained from transmitter, how much power can be directed towards the receiver, how much power is lost over the link, and at the transmitter and receiver, and how much is left at the detector? What margin is necessary above the minimum detectable signal for the detector being used? Essentially the problem is to ensure that the signal level at the detector is large enough to produce a satisfactory output for a large part of the year. Since the satellite distance is fixed, the attenuation (except for affect of rain) is also fixed, and it is high.

In satellite communications the direction of transmission is indicated by the term used: the downlink is transmission from satellite to earth station and the uplink is transmission in the opposite direction.

As we have mentioned before, communications by satellite impose enormous problems on systems designer. In the uplink we have availability of high intensity transmission beam; because the transmitter is ground based and therefore power is not a problem, coupled with a sensitive receiver on the satellite. While in the downlink we have a low power source in the satellite and a highly sensitive receiver in the earth station. However, this presupposes that the earth station cost is not a constraint. For public utility applications such as telephony, cost will not be a limiting factor; the high cost of an expensive receiving station can be spread over a very large number users. In direct broadcast television however, the story is different. A single user has to pay for receiver and therefore its cost must be low. This means that the earth station will be ‘basic’.

****Source : Telecommunication Engineering ; J Dunlop and D G Smith; Chapman &Hall; London

THE OPTICAL FIBER COMMUNICATION

The optical components of fiber communication are, in simple term, a light emitter, which initiates the optical signal, a fiber transmits it, and a detector which receives it and converts it into an electrical equivalent. If several fibers need to be joined, end to end, the couplers must ensure that the fibers are correctly aligned and butted, to reduce any joining losses to a minimum. Each of these components has essential ancillary parts; the detector and emitter are driven by stabilized voltages, and mounted in such a way that maximum transfer of light between them and the fiber is achieved. The fiber itself must be clad in short protective coating and made up into a cable that withstand the rigours of installation over long distance.

Optical fiber communications present the most exciting, and probably the most challenging, aspect of modern systems. Fibers are exciting because they seem to offer so many benefits ---low cost, enormous bandwidth, very small attenuation, low weight and size, and very good security again external interference. Physically, fibers occupy very little space, and they are so flexible that they can be used in places that would not be accessible to conventional cable. An optical fiber is, in essence, a dielectric wave guide. It has been known for a long time that high-frequency electromagnetic energy can be transmitted along a glass or plastic rod and, indeed, observation shows that short rods are translucent to light. However, two factors prevented that knowledge from being used to product useful light guides: (1) energy leaked from outside of the dielectric to the surrounding air (2) the attenuation was so large that worthwhile lengths could not be achieved. The first difficulty though virtually insurmountable at microwave frequencies, can be overcame in the optical and infrared parts of spectrum by enclosing the guide in cladding of similar material, but which has slightly smaller refractive index. The boundary between the cladding and the core acts as a reflecting surface to transmitted light. The second problem that of high attenuation, could be reduced only by refining the methods of producing and drawing the glass so that the impurities and irregularities were reduced to a minimum. The attenuation now achievable in the laboratory is almost as low as possible, at about 0.2 db/Km. Fiber of varying quality are used for communications, but when distance are significant, care is taken to ensure that lowest attenuation possible is achieved. This involves choosing the best operating frequency for particular fiber material, and ensuring that any contaminating elements are remove from the glass during manufacture. Before considering the loss mechanism inherent in any fiber, we will look at the different fibers used, and examine, with the help of ray theory, the way in which light propagates along an optical waveguide.

****Source : Telecommunication Engineering ; J Dunlop and D G Smith; Chapman &Hall; London

FLUORESCENT LAMP

Fluorescent lamp is a special of the arc lamp. In a fluorescent lamp the glass case of lamp tube is coated with a fluorescent powder consisting primarily of phosphors. Fluorescent is the property of material to reemit radiation in the visible range of wavelengths when irradiated by energy at wavelength outside the visible range. In a fluorescent lamp an arc is created in a mercury vapor. The mercury vapor emits photons at visible and ultraviolet wavelengths. These ultraviolet (253.7 nm) photons cause the lamp coating to fluoresce. The fluorescence caused by the interaction of the ultraviolet photons and the lamp coating results in a concentration of the emitted energy in visible region. For a given watt of input electrical power, a fluorescent lamp will have more emitted energy in the visible spectra than a incandescent lamp. The input power not radiated as visible light is given off as infrared radiation and conducted heat.

**** Sumber : Optoelectric Devices and Principles; William J Mooney; Prentice Hall; New Jersey;1991