Elektr tizimlari - Electrical systems

Elektr tizimlari butun dunyo bo'ylab kuchlanish va kamroq tanqidiy chastotada farqlanadi. Elektr vilkalari va rozetkalari ham turlicha bo'ladi va qurilmangizdagi vilkasini rozetkaga boshqa joydan qo'yish jismonan imkonsiz bo'lishi mumkin. Elektr qurilmalaringizdan maqsadingizda xavfsiz foydalanishini ta'minlash uchun bir necha qadamlarni bajarishingiz mumkin.

Tushuning

Kuchlanish va chastota

OGOHLANTIRISH: Bu juda muhimdir qurilmani faqat u uchun mo'ljallangan diapazonda voltajga ulang. Barcha holatlarda loyihalash spetsifikatsiyasidan tashqarida kirish voltajidan foydalanish juda yomon fikrdir. Ayniqsa, 110 V ga 230 V quvvatga mo'ljallangan qurilmani ulash juda xavfli bo'lishi mumkin; qurilmaga katta zarar etkazish xavfi mavjud va u yong'in chiqishi yoki hatto portlashi mumkin! Oddiy rezistiv yuk uchun kirish voltajini ikki baravar oshirish quvvat va issiqlikni to'rt baravar oshiradi, va bu har qanday yuk uchun o'rtacha birinchi taxminiydir. Yuqori kuchlanishli (220-240 V) moslamani past kuchlanishli quvvat manbaiga (110 V) ulash to'liq xavf tug'dirmaydi, ammo, aksincha, bu juda xavfli emas. Hech qachon elektr vilkasi mos kelishi sababli kuchlanish to'g'ri deb o'ylamang.

Dunyo xaritasi kuchlanish va chastota bilan bo'yalgan.
Sariq soyalar: 100-127 V, 50 Hz
Qizil soyalar: 100-127 V, 60 Hz
Moviy soyalar: 220-240 V, 50 Hz
Yashil soyalar: 220-240 V, 60 Hz

Siz foydalanmoqchi bo'lgan qurilma yoki zaryadlovchi qurilmaning orqa tomoniga qarab, "kirish" raqamlarini topishdan boshlang. Agar kirish "100–240 V, 50/60 Hz", bu dunyoning istalgan nuqtasida to'g'ri vilkalar bilan ishlaydi. Ushbu kirish imkoniyatlarini qamrab oladigan uyali telefon zaryadlash moslamalari yoki noutbukning quvvat manbalari kabi sayohat uchun mo'ljallangan qurilmalarda juda keng tarqalgan, ammo uni tekshirish kerak har qanday qurilma.

Agar sizda voltaj va chastotani qoplagan bo'lsangiz, ga o'tishingiz mumkin vilkalar, rozetkalar va adapterlar bo'limi. Agar yo'q bo'lsa, bu erda o'qishni davom eting.

Elektr energiyasining farqlari bilan kurashish qo'rqinchli bo'lishi mumkin, ammo aslida bu juda qiyin emas. Faqat ikkita asosiy turi mavjud elektr tizimlari dunyo bo'ylab turli xil bilan ishlatilgan jismoniy aloqalar:

• 100-127 volt, 60 Hz chastotada (umuman olganda: Shimoliy Amerika, shu jumladan Markaziy Amerika, Yaponiya)
• 220-240 volt, 50 Hz chastotada (umuman olganda: ba'zi istisnolardan tashqari, qolgan dunyo)

Ba'zida, 50 Hz da 100-127 voltni topasiz, masalan Tokio va ba'zilari Karib dengizi orollar. Boshqa tomondan, 60 Gts chastotada 220-240 volt, masalan Janubiy Koreya, Peru, ba'zi davlatlar Braziliya va Gayana. 60 Hz dan foydalanadigan bir nechta boshqa mamlakatlar ichki bo'linishga ega, ba'zi joylarda 100-127 volt, boshqalarda 220-240 volt, masalan Braziliya, Filippinlarva Saudiya Arabistoni. Ushbu mamlakatlar bo'ylab yangi manzilga sayohat qilishda har safar juda ehtiyot bo'ling va kuchlanish haqida so'rang.

Kemalardagi kuchlanish va chastota kemaning qurilgan joyiga va u qaerda ishlatilishi yoki ishlatilishiga qarab o'zgaradi. O'rindiqdagi samolyotlar universal ravishda 115 voltli 60 Hz dan foydalanadi.

Agar sizning qurilmangiz uchun kuchlanish va chastota sayohat qilgan joyingiz bilan bir xil bo'lsa, u holda siz faqat elektr vilkasi haqida qayg'urishingiz kerak. Aksariyat qurilmalarda voltaj bardoshligi 10 foizni tashkil qiladi, shuning uchun 220 dan 240 voltgacha yoki 110 dan 120 voltgacha bo'lgan farq haqida tashvishlanishning ma'nosi yo'q.

Agar mahalliy ta'minot tomonidan taqdim etiladigan kuchlanish sizning qurilmangiz tomonidan qabul qilingan oraliqda bo'lmasa, u holda sizga kerak bo'ladi transformator yoki konvertor kuchlanishni aylantirish uchun. Aksariyat sayohat aksessuarlari manbalari ularni taklif qiladi va eng ekzotik ehtiyojlardan tashqari barcha ehtiyojlarni hal qilish uchun bir nechta vilka adapterlari bilan ta'minlanadi.

Bunga qo'shimcha ravishda siz 12 yoki 24 voltdan foydalanishingiz mumkin DC tizimlari kameralar va mobil telefonlar kabi kichik moslamalarni zaryad qilish uchun mashinalar va qayiqlar yoki kompyuterdagi USB portining 5 voltli doimiy kuchi (va avtobuslarda, qayiqlarda, quyosh energiyasi bilan ishlaydigan uylarda va hokazo).

Vilkalar, rozetkalar va adapterlar

A qo'shishga imkon beruvchi qurilma vilka (qurilmangizdagi erkak ulagich) boshqasiga aylantiring rozetka (devordagi ayol konnektor) - bu an adapter: bular kichik va arzon. Masalan, o'rtasida Britaniya va Germaniya, sizga faqat adapter kerak. Siz to'rtburchaklar fazani / jonli va neytral tirgaklarni dumaloq nemislarga bog'laydigan va nemis rozetkasi kutgan joyga ("Yer") qo'yadigan inglizcha vilkasini adapterga o'rnatasiz. Keyin, siz borishga tayyormiz.

Afsuski, dunyoda juda ko'p turli xil vilkalar mavjud. The eng keng tarqalgan beshta standart quyidagilar:

Rasm	Ism	Tavsif	Foydalanish hududlari	Kuchlanish	Izohlar
	A / B turini tanlang "Amerikalik"	Ikki vertikal pim, dumaloq tuproq pimi	Shimoliy va Markaziy Amerika, Tailand, Yaponiya, Tayvan	odatda 100–127 V	Tailand va Filippinda 220–240 V kuchlanish
	C / E turini kiriting "Frantsuzcha"	Ikki dumaloq pin, teskari dumaloq zamin	Frantsiya, Belgiya, Polsha, Chexiya, Slovakiya	220–240 V	Ko'pgina vilkalar va adapterlar E va F tipidagi rozetkalarga mos ravishda ishlab chiqilgan
	C / F turini kiriting "Schuko"	Ikkita dumaloq pim, tuproq uchun yon kontakt	Evropaning aksariyat qismi, Rossiya, Janubiy Koreya	220-240 V
	G turi "Ingliz"	Uchta to'rtburchaklar pim	Britaniya orollari, Kipr, Malayziya, Singapur, Gonkong (vaqti-vaqti bilan Hindiston va O'zbekiston)	220–240 V
	I toifa "Avstraliyalik"	Ikki qiya pim, vertikal tuproq pimi	Avstraliya, Yangi Zelandiya, Tinch okean orollari, Xitoy, Argentina	220-240 V	Xitoy vilkasi teskari bo'lib, AU / NZ vilkasidan bir oz uzunroq pinalarga ega.

Amaldagi vilka turiga qarab ranglangan dunyo xaritasi

Universal vilka adapteri

Agar sizning qurilmangizda ushbu vilkalardan biri bo'lsa va siz uni boshqalarga moslashtirsangiz, siz mahalliy kuchlanish va chastotani boshqaradigan uskunalar uchun dunyoning 95 foizini qamrab olasiz. Asosiy istisnolar Hindiston va Janubiy Afrika. A va C tipidagi adapterlar va dan C ga G juda kichik va arzon; A turini G ga yoki G turini boshqa narsaga aylantirish, aksincha ko'pincha katta hajmdagi modelga muhtoj.

Havaskorlar uchun: agar siz adapter topolmasangiz va uzoqroq tursangiz, boradigan joyingizga alohida vilka sotib oling, mavjud vilkasini olib tashlang va yangisini ulang. Adapterlardan farqli o'laroq, vilkalar har doim mavjud va ular odatda arzonroq. E'tibor bergan: buni nima qilayotganingizni bilsangizgina sinab ko'ring! Tajribasiz bo'lsangiz, yong'in va / yoki elektr toki urishi mumkin. Shuningdek, simlarning ranglari va faza / jonli va neytral pimlarning yo'nalishi mamlakatlar o'rtasida ham farq qilishi va ba'zi eski qurilmalarda har xil bo'lishi mumkinligiga e'tibor bering; ba'zi mintaqalarda bir fazaning o'rniga ikkita fazani neytralga ulash mumkin.

Yana bitta murakkablikni ko'rib chiqish kerak: har qanday ikkita pinli rozetka asossiz, lekin uchta pinli vilkalar hammasi asosli ("Topraklanmış"). Ishga asos topishga urinish hayotni yanada qiyinlashtiradi, chunki C, E, F, H, J, K, N rozetkalari va D va L ning ba'zi versiyalari quvonch bilan C asossiz vilkasini qabul qiladi, lekin ishlamaydi. o'zlaridan tashqari har qanday asosli variant emas uchta pimni ikkita pimga aylantirish uchun adapterdan foydalaning: bu sizning elektr toki urishi va boshqa elektr toklari ta'siriga tushib qolishingiz mumkin.

Oxirgi ogohlantirish so'zi: ko'plab rivojlanayotgan mamlakatlar foydalanadi ko'p vilka A va C tiplarini qabul qiladigan (aytaylik) rozetkalar. Elektr vilkasi mos tushgani uchun kuchlanish to'g'ri deb o'ylamang, chunki A toifa A toifasidagi S soket hali ham 220 V quvvatga ega va Amerika (110 V) A tipidagi qurilmalarni yo'q qilishi mumkin.

Transformatormi yoki konvertormi?

220-240 V kuchlanishli asbobni 110 V kuchlanishli quvvatda ishlatish uchun sizga transformator kerak.

Agar siz 220-240 V kuchlanishli 110 V kuchlanishli qurilmadan foydalansangiz, siz transformatordan ham foydalanishingiz mumkin, lekin konvertor yordamida tejashingiz mumkin.

Agar sizning qurilmangiz faqat isitish elementi yoki soch turmaklagichi yoki kurutgichi kabi mexanik dvigatelga ega elektr moslamasi bo'lsa, unda siz shunchaki konvertordan foydalanishingiz mumkin, ammo sizning transformatoringiz yoki konvertoringiz qurilmangiz uchun zarur bo'lgan amper va vattni etkazib berish uchun to'liq baholanganligiga ishonch hosil qiling. Agar sizning qurilmangiz shunday bo'lsa elektron va kompyuter, printer, televizor, mikroto'lqinli pech, videokamera yoki hatto batareyani zaryadlovchi kabi elektron chiplardan yoki sxemalardan foydalanadi, sizga transformator kerak bo'ladi.

O'zingizning qaroringiz deb hisoblagan narsani sotib olishdan oldin, quyidagi munozarani tushunib oling.

Transformatorlar

Pastga tushadigan konvertor

• Transformatorlarning ikki xil turi mavjud: "faollashtirmoq" va "pastga tushmoq". Bosqichli transformatorlar sizga imkon beradi yuqori voltli qurilmani past kuchlanishli elektr rozetkasiga ulang (masalan, AQShda Buyuk Britaniya qurilmasidan foydalanish). Pastga tushadigan transformatorlar sizni ulashga imkon beradi past kuchlanishli qurilma yuqori voltli rozetkaga (masalan, Buyuk Britaniyada AQSh qurilmasidan foydalanish). Ba'zi transformatorlar ikkalasini ham taklif qiladi. To'g'ri turdan foydalanishga e'tibor bering: agar siz 110 dan 220 V gacha kuchaytirgich transformatorini 220 V rozetkaga ulagan bo'lsangiz, siz 440 V va qovurilgan qurilmani olasiz.

• Bundan tashqari, quvvat darajasi (vatt) sizning transformatoringiz qurilmangiznikidan kamida 10% ko'proq; aks holda, transformator haddan tashqari qizib ketishi va hatto olovga tushishi mumkin. Transformatorni sotib olishdan oldin, "kirish" raqamini qidiring: odatda qurilmaning vilkasidan ushlab yoki qo'llanmasida. Ba'zilar vattni namoyish etmaydilar, lekin siz shunchaki kuchlanishni (V) va oqimni (amper (A)) ko'paytirish orqali ishlashingiz mumkin; agar u milliamp (mA) bo'lsa, 1000 ga bo'ling). Olingan ko'rsatkich vatt bilan bir xil.

• Transformatorlar ikkala elektron qurilmalarda (masalan, chiplar va sxemalar bilan) yoki elektr jihozlarida (masalan, isitish elementlari va dvigatellari bilan) ishlatilishi mumkin. Ular odatda konvertorlarga qaraganda ancha uzoqroq ishlashi mumkin.

Konverterlar

Engil va arzonroq bo'lgan ushbu qurilmalar 1600 vattgacha quvvatga ega katta quvvat yuklarini ko'tarishi mumkin, lekin uni kuchaytirish emas, balki faqat pastga tushirish kuchlanishi. Ular 220-240 V kuchlanishli 110-120 V gacha bo'lgan mamlakatlarga sayohat qilish uchun mos keladi. bir vaqtning o'zida faqat bir yoki ikki soat, emas doimiy ravishda. Yuqorida aytib o'tilganidek, ularni elektron qurilmalar bilan ishlatish mumkin emaskompyuterlar, printerlar, videomagnitafonlar va hattoki batareyalarni zaryadlovchi qurilmalar kabi mikrosxemalar yoki sxemalarni ishlatadigan qurilmalar.

Hozirgi kunda ko'plab elektron qurilmalar konvertor bilan ta'minlanadi, u elektr tarmog'iga ulanadi va oqimni DC ga aylantiradi. Ammo, agar bu begona kuchlanishni qabul qilmasa (vilkasini tekshiring) emas orqasida ikkinchi konvertorni joylashtiring. Buning o'rniga siz og'irroq transformatordan foydalanishingiz kerak. Yaxshiyamki, so'nggi bir necha yil ichida tobora ko'proq qurilmalar universal kuchlanishli AC / DC konvertori bilan ta'minlangan bo'lib, sizga eng ko'p vilka adapteri kerak bo'ladi.

Chastotani (Hz)

12 V dan 230 V gacha 50 Gts doimiy / o'zgaruvchan inverter

O'zgaruvchan tokda (AC) voltaj sinus to'lqin shaklida musbatdan salbiyga va orqaga qaytadi. Bir soniyada voltaj aylanishlarining necha marta o'zgaruvchan tok chastotasi va gerts (Hz) bilan ifodalanadi. Buning aksi to'g'ridan-to'g'ri oqim (doimiy oqim) bo'lib, unda kuchlanish vaqt o'tishi bilan doimiy bo'lib qoladi. O'zgaruvchan tok elektr tarmog'ida ishlatiladi, chunki transformator yordamida kuchlanishni osongina oshirish yoki kamaytirish mumkin. Ushbu oqim batareyani zaryad qilish yoki elektron qurilmalarni ishlatish uchun doimiy oqimga aylantiriladi.

Odatda chastota muammo emas - aksariyat sayohat buyumlari 50 yoki 60 Hz da ishlaydi. Agar barcha elektr jihozlari issiqlik yoki yorug'lik ishlab chiqaradigan bo'lsa (lyuminestsent yorug'likdan tashqari), unda chastotaning ahamiyati yo'q. Yaponiya bu alohida holat: Sharqiy Yaponiya (masalan, Tokio) 50 Gts dan, g'arbiy Yaponiya (masalan, Osaka) esa 60 Gts dan foydalanadi. Yaponiya bozori uchun ishlab chiqarilgan uskunada 50 Hz yoki 60 Hz ni tanlash uchun kalit bo'lishi mumkin.

Chastotani kvars bo'lmagan soatlarga va dvigatellari bo'lgan qurilmalarga ta'sir qilish ehtimoli katta. Ular tezroq yoki sekinroq ishlashlari mumkin va natijada uzoq muddat zarar ko'rishi mumkin. Shunga qaramay, ba'zi motorli qurilmalar 50 yoki 60 Gts chastotada to'g'ri ishlashi mumkin, ayniqsa ular batareyalar bilan ishlasa. Faqat yorliqqa yoki vilkaga qarang.

Agar sizning qurilmangiz qayta zaryadlanuvchi batareyada, masalan, noutbukda va mobil telefonda ishlayotgan bo'lsa, u 50 yoki 60 Gts chastotada ishlashga teng darajada mos bo'lishi kerak. Buning sababi shundaki, zaryadlovchi moslama elektr ta'minoti uchun o'zgaruvchan tokning elektr energiyasini doimiy oqimga aylantiradi. Biroq, o'zgaruvchan tokni doimiy tokga aylantiradigan katta qurilmalar bilan ishlar yanada murakkablashadi. Katta konvertorlar ishlab chiqaradi harmonikalar, bu boshqa elektr jihozlariga xalaqit berishi mumkin. Harmonikani kamaytirish uchun filtrlardan foydalanish kerak va bu filtrlar odatda faqat bitta chastotaga mo'ljallangan. Agar siz ham kuchlanishni o'zgartirishingiz kerak bo'lsa (chunki sizning qurilmangiz kuchlanishi elektr tarmog'idagi voltajdan farq qiladi), siz qila olmaydi kommutatsiya tipidagi konvertordan foydalaning. Siz og'irroq bo'lgan yadroli transformatordan foydalanishingiz kerak. Agar shubhangiz bo'lsa, ishonchli elektr tovarlari sotuvchisiga murojaat qiling.

Agar sizning qurilmangiz boshqa chastotada ishlamasa (kuchli dvigatellar va kvars bo'lmagan soatlar), nisbatan kam variant mavjud. Voltajdan farqli o'laroq, chastotani transformatorlar o'zgartira olmaydi. Chiziq chastotasini o'zgartirishning yagona keng tarqalgan usullari bu mexanik quvvatga va orqaga (katta dvigatel generatori to'plami bilan) yoki elektronni doimiy va orqaga (inverter yordamida) aylantirishdir.

A 12 V doimiy o'zgaruvchan tok o'zgaruvchisi ko'pincha transport vositalaridan foydalanish uchun sotiladi. Ko'plab arzon ommaviy versiyalar sinus to'lqin o'rniga "arra tish" to'lqinini chiqaradi; bu soatlarning chastotasi va ba'zi elektron qurilmalar vaqtini ushlab turishi uchun muammo tug'dirishi mumkin. (Sinusli to'lqinli invertor yuqori narxda maxsus buyurtma bo'lishi mumkin.) Quvvat ham juda cheklangan; masalan, og'irroq tuyulgan 15 A dan 12 V marta 180 Vt quvvatga ega bo'ladi (yoki yo'qotishlarni hisobga olgandan keyin kamroq) - bu 120 V da bir yarim amper yoki 240 voltda shunchaki 0,75 amper.

Boshqa variant - ko'pincha kompyuter uskunalari uchun ishlatiladigan "uzluksiz quvvat manbai" (UPS). Narxlari va o'lchamlari turlicha, agar elektr tarmog'idagi kuchlanish mos kelmasa, sizga bir xil kuchga ega bo'lgan og'ir yadroli transformator kerak bo'ladi. Agar kerak bo'lsa, "toza sinus to'lqin" chiqishini tekshirishni unutmang. UPS volt-amper (VA) da quvvat xususiyatiga ega bo'lishi mumkin. Bu quvvatga mos keladi, shuningdek, kuchlanish bo'linib ketganda maksimal oqim chegarasini nazarda tutadi.

Texnika

Ushbu zaryadlovchini 230 V rozetkaga ulaysizmi? Siz qilmasligingiz kerak.

Agar siz yangi jihozlarni sotib olsangiz, kuchlanishni tekshirishga odatlaning. Ikkita kuchlanishli sochlarni to'g'rilash vositasi sizga bitta voltajdan ko'proq xarajat qiladi va sayohat qilishda katta qiyinchiliklarni tejaydi.

Noutbuklar

Deyarli barcha noutbuklar (shu jumladan ichki quvvat manbalari bilan) 100 dan 240 voltgacha va chastotasi 50 dan 60 gigacha ishlaydi. Boshqacha qilib aytganda, sizga konverter / transformator kerak bo'lmaydi; aksariyat quvvat manbalari to'g'ridan-to'g'ri ularga bosib chiqarilgan diapazonlarga ega, shuning uchun ularni ko'rib chiqing. Siz adapter sotib olishingiz kerakligini tekshirish uchun siz hali ham boradigan mamlakat uchun rozetkaga mos keladigan vilkasini tekshirishingiz kerak bo'ladi.

Noutbukning quvvat manbalari odatda yomon yoki har xil ta'minotni qabul qilishda juda yaxshi. Ko'pgina ishlab chiqaruvchilar bir xil turdagi ta'minotdan foydalanadilar, shuning uchun ehtiyot qismlarni olish juda qiyin emas. HP / Compaq tomonidan ishlatiladigan tur juda keng tarqalgan. Ebay kabi saytlardan zaxira ta'minotini olish juda oson va arzon. Biroq, uning asl nusxasi emas, balki arzon nusxasi ekanligiga ishonch hosil qiling. Zaxira bilan siz noma'lum ta'minot bilan xavf tug'dirishingiz mumkin. Albatta, sizning tizza kompyuteringiz ichki ta'minotga ega bo'lgan kam sonli kishilardan biri bo'lsa, hech qanday xavf tug'dirmang.

Agar siz noutbukni olib ketayotgan bo'lsangiz, uni USB portlari yordamida boshqa narsalarni zaryad qilish uchun ishlatishingiz mumkin. To'g'ri kabellarni olib kelishingizga ishonch hosil qiling - USB qurilmasi kabeli har qanday micro-USB, USB-C, Apple 30-pin yoki Apple Lightning ulagichlarida uzilishi mumkin. Mobil telefon. Raqamli kameralar tez-tez USB-dan nostandart kabel bilan quvvat oladilar, chunki ishlab chiqaruvchilar xususiy ulagichlardan foydalanadilar.

Ko'pgina planshet kompyuterlar standart microUSB ulagichidan 5V quvvat olishlari mumkin, ammo istisnolar mavjud (Acer standart ko'rinishga ega USB ulagichlaridan foydalanadigan bir nechta modellarni ishlab chiqaradi, lekin faqat standart bo'lmagan voltajda xususiy quvvat oluvchidan quvvat oladi).

Radiolar

Qisqa to'lqinli radio qabul qilgich

Elektr energiyasi bilan bog'liq masalalar hal qilinib, radio kerakli chastotalarni boshqargan taqdirda, radiolar mamlakatdan mamlakatga almashtirilishi mumkin. Bir nechta mamlakatlarda ishlatiladigan aniq FM diapazoni boshqacha, shuning uchun siz barcha stantsiyalarga kira olmaysiz. Amerikada faqat toq kanallar (88.1, 88.3, ​​100.1 va boshqalar) ishlatiladi. Faqat AQSh bozoriga mo'ljallangan radio chet elda yaxshi ishlamaydi. Ayniqsa, Yaponiyada keng tarqalgan 87,5 MGts dan 108 MGts gacha emas, balki 76 MGts dan 90 MGts gacha bo'lgan FM diapazoni mavjud. Avvalgi mamlakatlar Sovet Ittifoqi shunga o'xshash tasma ham ishlatgan. O'rta to'lqin diapazoni uchun kanal oralig'i (har bir amaldagi chastota orasidagi farq) 9 kHz (Evropa, Osiyo, Afrika va Okeaniya) yoki 10 kHz (Amerika) bo'lishi mumkin. Raqamli displeyli radioeshittirishlar va sozlash uchun tugmalar qaysi kanal oralig'idan foydalanilishini tanlash uchun kalit yoki sozlagichga ega bo'lishi mumkin. Bu holda, ular mo'ljallangan bozor tashqarisida to'g'ri ishlamaydi. Eskirgan analog-dial-tyunerlar qilmang ushbu cheklovga ega.

Agar sizga xalqaro sayohat uchun yangi radio kerak bo'lsa, quyidagilarni o'z ichiga olganini ko'rib chiqing qisqa to'lqinli guruh (SW). Shunday qilib, siz butun dunyodan yangiliklar va ma'lumotlarni qabul qilishingiz mumkin (BBC, Deutsche Welle, Amerika Ovozi, Avstraliya radiosi va boshqalar) Qisqa to'lqinli eshittirishlar o'rta to'lqinlardan yuqori chastotada (MW, ko'plab radiolarda AM deb belgilangan) band va juda uzoqroq sayohat qiling, ayniqsa qorong'i tushgandan keyin, lekin shovqinli va signalning pasayishiga moyil. So'nggi o'n yil ichida AM / SW / FM radiostantsiyalarining hajmi va narxi ancha pasayib ketdi va ulardan foydalanish ancha osonlashdi. Ba'zi qisqa to'lqinli radiolar sozlanishi chastotali osilatorni (BFO) ta'minlaydi; standart eshittirishni qabul qilish uchun talab qilinmasa ham, bu SSB (bitta yon tarmoqli) havaskor radio signallarini qabul qilishga imkon beradi. Ko'pgina teleradiokompaniyalar qisqa to'lqinli dasturlarini to'xtatdilar (masalan, BBC 2008 yilda Evropaga qisqa to'lqinli ko'rsatuvlarini tugatdi), shuning uchun siz tashrif buyurgan mintaqada siz eshitmoqchi bo'lgan tillarda hanuzgacha qisqa to'lqinlar uzatilishini tekshiring.

Qisqa to'lqinli radio WWV (2,5, 5, 10 va 15 MGts) ga yoki butun dunyo bo'ylab turli xil davlatlarning o'xshash signallariga sozlash orqali aniq vaqt manbai sifatida ishlatilishi mumkin. Sohil VHF FM radiosi doimiy ravishda yoki dengizdagi VHF chastotalarida belgilangan vaqtlarda ob-havo ma'lumotlarini taqdim etadi (ba'zi ma'lumotlar dengizga kirmaganlar uchun foydali bo'lishi mumkin). Shuningdek, standart FM radioeshittirish diapazonidan tashqarida boshqa o'ziga xos ob-havo chastotalari bo'lishi mumkin; Shimoliy Amerikada tornado yoki boshqa o'ta ob-havo zudlik bilan xavf tug'dirsa, ba'zi maxsus "ob-havo radiolari" signal beradi.

Raqamli radio

Raqamli radio ba'zi mamlakatlarda, asosan yuqori darajada rivojlangan va sanoatlashgan hududlarda qo'llaniladi. Eng keng tarqalgan tizimlar:

• DAB, asosiy Evropa standarti
• DAB, DAB standartining yangilanishi, ba'zi Evropa mamlakatlari va Avstraliyada qo'llaniladi
• DRM, Hindistonda va shaharlararo radioeshittirish uchun ishlatiladi
• Boshqa bir qator tizimlar cheklangan foydalanishga ega, jumladan HD Radio, Shimoliy Amerikada ishlatiladigan standart, T-DMB, Janubiy Koreyada ishlatiladigan DAB standartining bir varianti va Yaponiyada ishlatiladigan ISDB-tsb.

Raqamli radioning muvaffaqiyati har bir mamlakatda turlicha, lekin umuman Evropada keng tarqalgan. Norvegiyada DAB va DAB radiosini qabul qilish hozirda juda yuqori bo'lib, mamlakat FM radioeshittirish moslamalarini 2017 yilda o'chirib qo'ydi; Shveytsariya 2023 yilda ham bu yo'ldan borishni rejalashtirmoqda. Buyuk Britaniya, Niderlandiya va Germaniya singari boshqa bir qator Evropa davlatlari DAB radioeshittirishlarini keng taklif qilishmoqda, boshqa mamlakatlar, shu jumladan Ispaniya va Shvetsiya, raqamli radio xizmatlarini taqdim etishni boshladilar. Amerika Qo'shma Shtatlari va Avstraliya kabi boshqa mamlakatlar raqamli radio xizmatlarini rivojlanmagan va analog radioga juda qaram bo'lib qolmoqda, hatto Finlyandiya va Portugaliya kabi juda rivojlangan mamlakatlarda ham raqamli radio xizmati umuman yo'q. Kanada DABni bir nechta shaharlarda sinovdan o'tkazdi, faqat 2010 yilda uni o'chirib qo'yishdi va 2014 yilda HD radioeshittirishlarini sinovlari boshlandi. Umuman olganda, analog radiolar ko'pchilik sayohatchilar uchun etarli bo'ladi, ammo Evropaga sayohat qilishni rejalashtirganlar DAB va DAB imkoniyatlarini ham o'z ichiga olgan radio sotib olishni xohlashlari mumkin.

Ikki tomonlama radio

Har bir mamlakatda radioeshittirishlar turli darajadagi davlat tomonidan tartibga solinadi va litsenziyalanadi, chunki juda kuchli yoki noto'g'ri chastotalarda uzatish boshqa stantsiyalarga xalaqit beradi. Bu Avstraliyalik O'z mamlakatida litsenziyani talab qilmaydigan 477 MGts chastotali UHF CB qurilmasi qabul qilinmasligi mumkin Shimoliy Amerika, bu erda barcha qo'shnilarning HDTV-laridagi 15-kanal yo'q qilinadi. Tadqiqotingizni qiling.

Ba'zi jihozlarni siz tashrif buyuradigan har bir mamlakat uchun qayta sozlash mumkin, ammo iste'molchilarning qayta jihozlanadigan uskunalari (yoki noqonuniy chastotalarda yuborish imkoniyatiga ega bo'lgan har qanday iste'mol uskunalari) ba'zi mamlakatlarda noqonuniy bo'lishi mumkin.

Uchun standartlar walkie-talkies va keng jamoatchilik uchun transport vositalariga o'rnatilgan ikki tomonlama radiolar kiradi FRS va GMRS (Amerika), PMR446 (Evropa), UHF CB (Avstraliya va Yangi Zelandiya), CB radiosiva MURS. Ulardan ba'zilaridan foydalanishga faqat bir yoki bir nechta mamlakatlarda, boshqalarga bir nechta davlatlarda ruxsat beriladi, lekin ruxsat berilgan chastotalar ko'pincha farq qiladi, shuning uchun radiodagi ba'zi kanallar noqonuniy, ba'zilari esa qonuniy chastotalarda mavjud emas. Bundan tashqari, signal chastotasi talablari ba'zi chastotalar uchun farq qiladi.

Ko'p kanallari dengiz VHF litsenziyalash talablari bilan dunyo bo'ylab mavjud, ammo alohida kanallarda foydalanish cheklovlari turlicha. Kichik hunarmandchilik Uyda faqat operatorlik litsenziyasi zarur bo'lganligi sababli chet elda dengiz chastotalarida XEI chaqiruvi kerak bo'lishi mumkin. Ba'zi litsenziyalar ITU tomonidan standartlashtirilgan va butun dunyo bo'ylab ozmi-ko'pmi amal qilishi kerak, dam olish yoki qirg'oq bo'ylab harakatlanish uchun boshqa litsenziyalar ichki suvlarda cheklanishi mumkin. Qurilishda dengiz radiosidan foydalanish faqat bitta chastotada ishlaydigan port ustalari, ob-havo stantsiyalari, marinalar yoki kanal, ko'taruvchi va buriluvchi ko'prik operatorlari kabi ob'ektlarga taqiqlanadi. Qo'ng'iroq qilish kanallari ham farq qiladi, chunki ba'zi mamlakatlar VHF 16-ni zahiradagi qo'ng'iroqlar uchun saqlab qo'yishadi. Mahalliy kanalga ajratilgan kanaldan suiiste'mol qilish minnatdorchilik bilan qabul qilinmaydi.

Ba'zi mamlakatlar chet elliklarni tan olishadi havaskor radio agar stansiyalar efirda to'g'ri aniqlangan bo'lsa va mahalliy chastotalar va quvvat darajalarida ishlayotgan bo'lsa, litsenziyalar; boshqalar qilmaydi. Ba'zilar xorijiy operatorga mahalliy litsenziyani berishlari mumkin. Katta antennalarga ega portativ radioamatör stantsiyalarni odamlar yashamaydigan orollarda vaqtincha "DXpeditions" deb joylashtirishning barcha sevimli mashg'ulotlari mavjud, shunda ham chet elda hamlar topish qiyin bo'lgan yana bir mamlakatni jurnallarga kiritishlari mumkin, ammo bir nechta davlatlar (masalan, "P5") Shimoliy Koreya) deyarli imkonsizdir, chunki ular hech kimni litsenziyalashmaydi.

2450 MGts kabi simsiz tarmoqlar Wi-fi va Bluetooth ehtimol biron bir shaklda mavjud bo'lishi mumkin, ammo bir nechta mamlakatlar barcha kanallardan foydalanishga ruxsat bermaydilar. Odatda tayanch stantsiyada (yoki Wi-Fi routerda) qaysi mamlakat chastotalaridan foydalanish mumkinligini belgilaydigan sozlama mavjud. Buni mavjud simsiz tarmoqqa ulangan har bir kompyuterda sozlash shart emas.

Uyali telefonlar mamlakat yoki mintaqa uchun noto'g'ri chastotalarda bo'lgan baza stantsiyani topa olmaydi va shunchaki tarmoqdan foydalanmaydi. Ular hali ham oflayn vositalar yoki VoIP telefonlari va Wi-Fi ulanishlari mavjud bo'lgan Internet-brauzerlar sifatida foydalanishlari mumkin.

Yozib olish va ijro etish moslamalari

Videoni ijro etishdan farqli o'laroq (bu mos kelmaydigan standartlar va bezovta qiluvchi mintaqaviy kodlash sxemalari buzilishi), yozib olingan audio xalqaro miqyosda etarlicha standartlashtirilgan. Uskunaning mintaqaviy kuchlanish va chastotaga mosligi to'g'risida odatiy ogohlantirishlar hanuzgacha amal qiladi; sinxron o'zgaruvchan dvigatel bilan ishlaydigan aylanadigan stol sizning vinil LP-laringizni noto'g'ri tezlikda o'ynaydi, chunki transformator faqat kuchlanishni o'zgartiradi, chastotani emas. Batareya bilan ishlaydigan yoki kristalli boshqariladigan qurilmalarga (masalan, MP3 pleerlarga), agar ular o'zgaruvchan tok adapteridan ishlayotgan bo'lsa ham, chiziq chastotasi ta'sir qilmaydi (shunchaki voltajni to'g'rilang!).

Mobil telefonlar va raqamli kameralar

Shuningdek qarang: mobil telefonlar

Eng so'nggi mobil telefonlar 5 voltli quvvat manbai sifatida USB-da standartlashtirilgan. Zaryadlovchilar 110 V va 240 V o'zgaruvchan tok uchun ham mavjud, shuningdek, avtoulovlarda 12 V doimiy tizim uchun adapterlar mavjud. Ikkala kuchlanishli zaryadlovchi qurilmalar ikkala tarmoq tizimini qo'llab-quvvatlaydi (garchi ba'zilariga adapter vilkasi kerak bo'lishi mumkin).

Qadimgi uyali telefonlarda keng ko'lamli nostandart ulagichlar va xususiy zaryadlovchilar ishlatilgan. 21-asr telefonlari (va smartfonlari) USB zaryadlovchilarini tobora ko'proq standartlashtirmoqdalar, lekin kabellar bir nechta ulagich turlaridan kelib chiqqan holda o'zgarib turadi. Micro-USB yoki USB-C odatda Android qurilmalarida qo'llaniladi. 2010-yillarning oxirlarida USB-C yuqori darajadagi Android qurilmalari uchun standart bo'lib qoldi va tobora pastroq qurilmalarda mavjud. Apple-ning iPhone-lari ushbu ishlab chiqaruvchining litsenziyalangan xususiy ulagichlariga ega kabelga muhtoj.

Uyali telefonlar uchun ulanishni olishda qo'shimcha muammolar mavjud. Smartfonlar odatda a ni olishlari mumkin Wi-fi chet elda ulanish (uni yoqish uchun etarli bo'lishi mumkin Internet-telefoniya) lekin belgilangan mamlakatning mobil tarmog'iga ulanish imkoniyati har xil; telefonlar noto'g'ri chastotada bo'lishi mumkin, mos kelmaydigan standartlardan foydalanish yoki bitta provayderga qulflangan bo'lishi mumkin.

Raqamli kameralar tarmoq ulanishiga muhtoj emas, lekin mos keladigan zaryadlovchi qurilmani talab qiladi. Ularning aksariyati USB-dan quvvat oladilar, ammo ko'plari xususiy ulagichga ega kabellarni talab qiladi. Ba'zi raqamli kameralar hali ham AA batareyalarini oladi va agar siz uzoq vaqt davomida elektr tarmog'idan foydalanmasdan sayohat qilishni rejalashtirmoqchi bo'lsangiz, ular yaxshi variant bo'lishi mumkin.

Standart batareyalardan foydalanadigan uskunalar

Batareyaning o'lchamlari va kuchlanishlari har joyda standart bo'lib turadi va rafdan tashqari batareyalarni ishlatadigan uskunalar bir-birining o'rnini bosadi. Ba'zi mamlakatlarda sifatli batareyalarni, ayniqsa ko'pchilik elektron uskunalarga zarur bo'lgan gidroksidi batareyalarni olish qiyin bo'lishi mumkin. Agar arzonroq batareyadan foydalansangiz, uni tugashi bilanoq va jihoz bir muddat ishlatilmay qolishi bilanoq sizib chiqishi mumkinligi sababli uni chiqarib oling.

NiCad va NiMH uchun ikkita kuchlanishli batareyali zaryadlovchilar odatda bitta voltajdan oshmaydi, ammo sotib olishdan oldin ushbu xususiyatni qidirib topishingiz kerak. Agar mavjud bo'lgan bitta kuchlanishli zaryadlovchi 12 voltli doimiy adapterdan foydalansa, 12 darajasida sifatli ikki voltli adapterni (110 V dan 240 V gacha) toping. VOltlar doimiy oqim darajasi bilan DC milliAmps) teng yoki undan yuqori va zaryadlovchining uchida bir xil o'lchamdagi vilka. (Agar zaryadlovchi hech qanday simsiz to'g'ridan-to'g'ri elektr tarmog'iga ulansa, bu mumkin emas.)

Ehtiyot bo'ling

Katta elektr tarmoqlari

Evropaning uch fazali rozetkasi

Ko'pgina mamlakatlarda elektr energiyasi ishlab chiqarish / savdo binolariga a uch fazali tizim. Sanoat uch fazali rozetkada uch xil kuchlanishli / fazali simlar va ixtiyoriy ravishda bitta neytral sim mavjud. Ular odatiy bo'lmagan yoki jismonan kattaroq ulagichlardan foydalanadilar (bir mamlakat uchun oddiy uy rozetkasi va rozetkasi bilan taqqoslaganda), odatda maksimal yuqori oqim va to'rtta yoki undan ko'p pim bilan uchta fazani va neytral yoki tuproqni joylashtirish uchun.

Oddiy maishiy savdo shoxobchalari doimo bir fazali. Ular ushbu fazali simlardan faqat bittasini va neytral simni oladilar. Uch fazali rozetkalar fabrikada bo'lishi mumkin yoki katta savdo yoki sanoat uskunalarini quvvat bilan ta'minlash uchun ishlatilishi mumkin. Ba'zi xususiy uylarda oshxonalar, suv isitgichlari va konditsionerlar kabi elektr energiyasiga muhtoj bo'lgan asboblar uchun uch fazali quvvat bo'lishi mumkin (odatda qattiq simli yoki maxsus konnektorlardan foydalaniladi). Siz tarqatish taxtasida yoki yirik mashinalar ishlatilishi mumkin bo'lgan joyda, masalan, ustaxonada sanoat tipidagi savdo nuqtalarini topishingiz mumkin. Ushbu savdo nuqtalarini oddiy xonalarda topa olmaysiz.

Nominal 120 V mintaqadagi yana bir variant - bu katta yukga ulangan, masalan oshxona xonasi yoki to'liq o'lchamdagi kiyim-kechak quritgichi bo'lgan 240 V 60 Gts chastotali markazlashtirilgan tizim. 240 V vilkaning ikkala pichog'i yon tomonga o'girilgan yoki katta tokni boshqarish uchun mo'ljallangan to'rtta pinli (ikkita kuchlanish simlari, neytral va himoya tuproqli) jismonan kattaroq vilka.

Ushbu nostandart ulagichlar odatda yuqori voltajlarga ega (Evropa sanoatining uch fazali chiqish quvvati 230 V dan to neytralgacha 400 V dan chiziqgacha; Kanadada va AQShda 600 V yoki 480 V gacha bo'lgan tarmoqlarda bir necha sanoat foydalaniladi. navbati bilan). Ular dvigatellari, katta konditsionerlari, sanoat / savdo pechlari va boshqa kuchga ega bo'lgan elektr jihozlari bilan ishlaydigan katta mashinalarni boshqarish uchun javob beradi.

"Avstraliya" vilkasini ishlatadigan mamlakatlarda siz vaqti-vaqti bilan odatdagidan kattaroq vertikal tuproq pimi bilan rozetkaga duch kelishingiz mumkin. Bu 15 A nominal rozetka; standart rozetka 10 A ga teng. Buyuk Britaniya va Evropaning savdo nuqtalari mos ravishda 13 A va 16 A darajasida bo'lganligi sababli, kichikroq maishiy texnika uchun foydalanish yaxshi.

Voltajdan va qancha fazalardan foydalanishidan qat'i nazar, mahalliy ta'minotning chastotasi (50 Hz yoki 60 Hz) o'zgarishsiz qoladi.

Yomon tarqatish tarmog'i bo'lgan mamlakatlarda bu noma'lum emas kuchlanishni kuchaytirish uchun 2 faza bo'ylab ulanadigan bitta fazali rozetkalar. Bu xavfli va elektron uskunalarga zarar etkazishi mumkin.

Umumiy qoida sifatida bunday qilma shaxsiy elektr buyumlaringizni to'g'ridan-to'g'ri noma'lum uch fazali tizimga ulashga harakat qiling.

Agar ko'rsangiz a nostandart (o'z mamlakati uchun) yoki katta ulagich, etkazib beriladigan kuchlanish yoki oqim ham nostandart bo'lishi mumkin (masalan, nominal ravishda 120 V bo'lgan hududda 240 V 60 Gts katta jihozni oziqlantirish yoki kichik uyni yoki uyni quvvatlantirish uchun yetarli tokni o'tkazib yuborish uchun o'lchash moslamasi) . Faqat ulanmang va yaxshilikka umid qiling.

Generatorlar

Dizel bilan ishlaydigan generator

Elektr energiyasini taqsimlash tizimlari to'liq rivojlanmagan ko'plab mamlakatlarda generatorlardan foydalanish odatiy holdir. Jeneratörler, shuningdek, vaqtincha qurilmalarni elektr energiyasi bilan ta'minlash, shuningdek, elektr energiyasi uzilishi paytida muhim xizmatlarni qo'llab-quvvatlash uchun elektr energiyasini etkazib berish uchun ishlatiladi. Jeneratör ta'minoti juda yaxshi bo'lishi mumkin; ammo, ko'p joylarda ular yomon va ulangan sezgir uskunalarga zarar etkazishi mumkin. Voltaj, chastota va to'lqin shakli shakli o'zgarishi mumkin (u silliq sinus to'lqin bo'lishi kerak). Ba'zi joylarda odamlar tezroq ishlash uchun generatorlarni o'zgartiradilar. Bu ko'proq kuchlanish va quvvat beradi, lekin chastotani ham oshiradi. Jeneratorning doimiy tezlikda ishlashini ta'minlaydigan qismi gubernator deb ataladi. Agar bu buzilgan bo'lsa, chiqadigan kuchlanish zarar etkazishi uchun etarlicha ko'tarilishi mumkin. Eng yaxshi maslahat - qimmatbaho jihozlarni etkazib berishga ulamaslik yoki hech bo'lmaganda tugatishingiz bilanoq uni o'chirib qo'ying.

Amaldagi generatorning sifatiga ishonchingiz komil bo'lmasa, bir nechta oddiy qoidalar mavjud. Agar u benzin / benzindan ishlasa, bu yomon: generator quvvatidan foydalanishga jiddiy munosabatda bo'lgan har kim dizel moyi bilan ishlaydigan tizimdan foydalanadi. Yaxshi sifatli generator past dvigatel tezligiga ega bo'ladi. 50 Hz uchun 1500 RPM yoki 60 Hz uchun 1800 RPM. Dvigatelning tezligi 3000 RPM yoki undan ko'p bo'lsa, bu yaxshi mashina emas. Yaxshi 12000 RPM benzin generatorini yaratish umuman mumkin; aksariyat hollarda bu shunchaki tejamli emas va shuning uchun ular modda uchun juda kam uchraydi.

Yoritgichlar

Yoritgichlar va ularning lampochkalari voltajga juda sezgir. Agar siz kuchlanish tizimlari o'rtasida siljigan bo'lsangiz, chiroq har ikkala tizimda ham ishlashga mo'ljallangan bo'lmasa, masalan past kuchlanishli adapter orqali lampochkalarni kuchlanishga mos ravishda o'zgartirishingiz kerak bo'ladi. Agar siz chet elda chiroq sotib olsangiz, mamlakatingizdagi elektr xavfsizligi standartlariga rioya qilish uchun uyga qaytgach, elektrchini chiroqni to'liq qayta tiklashingiz kerak bo'lishi mumkin. This may not be a problem for a one-off special item, but if you are going into the importing business it could be a show stopper.

Also watch out for the light bulb connection. In 100–127V systems this is often a screw connector while in 220–240 V systems it is often a bayonet connector. These connectors also come in at least two different sizes. Be sure you can obtain light bulbs of the right voltage, size, and connector shape in the country you intend to use the lamp, and at a reasonable price, or the lamp may become little more than junk when the bulb fails.

Note that fluorescent and LED lighting contains electronics and must use a heavy iron-core transformer to convert voltage. Converters are emas acceptable.

Some fluorescent units might be sensitive to changes in frequency (50 or 60 Hz) if it's not the same as what is specified. Most affected are fixtures with a large coil or inductor as "ballast" to limit the current into the bulb, as the impedance of these coils is directly proportional to frequency. Electronic ballasts usually convert the AC line directly to DC (and then to a higher-frequency AC), causing line frequency to be ignored.

Electric motors

The electric motors in things like refrigerators, vacuum cleaners, washing machines and other whiteware are often sensitive to frequency, the same goes for older hairdryers and electric shavers. Even if you use a step-up or step-down transformer, the different supply frequencies mean that motors will run at the wrong speed and quickly burn out. The larger and more powerful the motor is, the more this is true. Don't, for example, bring a vacuum cleaner from the US to Europe (or vice versa). It's almost guaranteed to fail—even if you have a voltage converter.

Electric shavers

A dual-voltage shaver socket

Hotels often provide a special electrical outlet specifically for electric shavers. They allow any voltage shaver to be plugged into them and be used safely in front of the bathroom mirror. They may also accept your cellphone adaptor or similar low power battery charging unit. Many electric shavers sold today are dual voltage 50/60 Hz and some will even recharge the battery at 12V DC (such as in an automobile). Check the label and instructions for compatibility.

Hairdryers

Hairdryers are a particular risk; if you accidentally plug your 100–120 V hairdryer into a 240 V outlet. you may find it catching fire in your hands! Newer models should have a thermal switch, though. Allow 15–20 min. for it to cool down, then use a voltage converter (if the dryer is 50 Hz compatible). Similarly, a 220–240 V hairdryer in a 120 V outlet may run slowly and not heat up enough. Most good hotels and motels will be able to supply a hair dryer, and it may even be a room fitting. However, it may be worthwhile buying or borrowing a hairdryer suited for the electrical system of countries you'll be traveling in.

Many new hairdryers sold in 100-120 V countries are dual voltage with settings for 100–120 V and 220–240 V. Even though it's motorized, it will work on either 50 or 60 Hz. Don't forget to lockout the high setting with a flat screwdriver or something similar. At 220–240 V, the low setting becomes as powerful as the high setting was at home (with 'low' unavailable).

Clocks

An electric clock of any sort is sensitive to voltage. If the voltage is doubled or halved, it will not function and may burn out. Furthermore, the electric frequency (50 or 60 Hz) is used in cheap clocks (such as many clock-radio style clocks) to keep the time. Thus, if a clock made for North America were used in Europe – even with a voltage adapter – it would lose 10 min/h! Obviously, not a great idea if you have a train to catch. The mains frequency is influenced by mismatched electricity supply and demand (a dip in frequency suggests a generator going offline or an increase in demand, and vice versa), and therefore will drift by up to 0.25 Hz either side of the nominal frequency. This may cause mains-powered clocks to become inaccurate over time. During 2017/2018, small but systematic deviations from 50 Hz in the European grid caused such clocks to go wrong by several minutes.

On the other hand, if the clock has a quartz crystal, this is used for the timekeeping, and it operates independently of the line frequency. Inexpensive, battery-operated, digital LCD travel clocks (with a push button back light) are also available. These are recommended for destinations with frequent blackouts. Often, a battery-powered alarm clock will be built into some other device, such as a pocket pager or mobile telephone; this clock usually still works even if the original paging or telephone service was unsubscribed years ago.

Video equipment

Digital terrestrial television systems worldwide.

DVD region codes

Blu-ray region codes

Before purchasing any video equipment, read the manual and warranty carefully. Televisions, many radios, video and DVD players, as well as videotapes, are often specific to the broadcast system used in the country that they are sold in, usually associated with the frequency of the country's electric current. For example, North America is 60 Hz and its television is 30 frames per second, while Europe is 50 Hz and its television is 25 frames per second. Unless you have an internationally compatible device, you may find your expensive looking system is little more than worthless junk in another country because it won't work with your country's broadcast system. Your warranty is probably only valid in the country of purchase, and you may need to return the goods to the place you purchased them from.

There are three main analog television broadcast systems:

• PAL, the closest to a worldwide standard, is used in the UK, Germaniya, much of western Europe as well as Avstraliya va Yangi Zelandiya.
• NTSC is used mostly in the Americas and some East Asian countries (notably Yaponiya, Janubiy Koreyava Tayvan).
• SECAM is originally from Frantsiya and was adopted by much of Eastern Europe va Yaqin Sharq.

There are various incompatibilities even within these supposed standards. For instance, Brazil uses a hybrid PAL/NTSC standard called "PAL-M". The system operates at the same resolution as NTSC (so DVDs and video tape are interchangeable with their NTSC counterparts, unless restricted by region coding), but the format of the over-the-air signal differs enough that PAL-M players and TV sets are useless outside the country unless they have a separate NTSC setting.

Likewise, there are multiple incompatible over-the-air digital television systems:

• DVB-T, the closest to a worldwide standard, originated in the European Union. Most locations which were PAL or SECAM in the analog era use this system.
• ATSC, North American standard, is used in South Korea (but not Japan).
• ISDB, Japan's own incompatible standard, has been exported to some South American countries but is otherwise rarely used.
• There's also a DTMB which is standard in mainland Xitoy; there has been no widespread international adoption of this system.

Again, there are incompatibilities even within each standard; for instance, some countries (such as Brazil) use MPEG4 while others use MPEG2.

The likely result of bringing a TV to another country with an incompatible system varies. If the voltage is wrong, the equipment will not work at all or will be damaged. This can be remedied with a line-voltage transformer; if the equipment is "120/240 V 50/60 Hz" a plug adapter or replacement power cord may suffice.

Even if the voltage is correct, the TV will not be able to receive programming over-the-air if the broadcast frequency or the signal format is wrong. Using the TV solely as a video monitor (instead of relying on the TV's built-in over-the-air tuner) will give mixed results:

• A signal which is merely on the wrong frequency will need to be tuned with a converter box; the aerial (or antenna) will need to be replaced for the correct bands. An over-the-air signal in the wrong format likely won't work if fed through an external tuner to the standard-definition analog "video in" jacks on a TV.
• Most standard-definition analog baseband "video in" connections (such as "composite video" or "S-Video") are tied to the local video system. NTSC won't mix with PAL/SECAM at all (as the number of lines and frame rate don't match). Mixing PAL with SECAM is likely to produce a monochrome image.
• Analog HDTV signals (such as VGA, "component video" or RGB) fare somewhat better as there are separate inputs for each color and frame rates are more flexible.
• Computers (and their video displays) are standardized relatively well. Digital formats like DVI, HDMI, and DisplayPort are likely to be compatible internationally. Don't be surprised if your foreign TV works perfectly well as a computer video monitor, but is non-functional for watching videotapes in the local format or tuning stations over-the-air with the built-in tuners.

Don't forget about cable TV frequencies; they may not be the same, even if everything else is. Furthermore, many countries have switched or are switching to digital over-the-air broadcasting (see dates by country on Wikipedia).

The final problem with transporting TVs is that many European countries, notoriously the UK, require a television licence to watch any live TV (over-the-air, cable, satellite, and even live-streams on the internet); the fees are used to fund public broadcasting such as the BBC. This even includes USB TV tuners for computers and laptops if they're capable of DVB reception. Licenses are typically in the range of €100-300/year, and fines for dodging the license can be hefty.

Bringing prerecorded tapes or discs with their player and the matching display/monitor to another country as a package will likely work if the line voltage is correct.

An attempt to mix and match local and imported pieces in the same system potentially has a few pitfalls:

• Technically, there is no such thing as an NTSC or PAL DVD disc, as all color information is the same for both. When discs are labelled as such, what they're referring to is the picture size and frame rate (i.e. number of frames per second) that are used in most (but not all) countries that have TV broadcasts on this same system. Many NTSC players cannot play PAL DVDs, unless that's a specific feature included (many Philips and JVC models include this). PAL DVD players are generally much better at playing NTSC, but it's not a certainty. If all else fails, a computer DVD-ROM can play any DVD movie, though there's a limit on how many times you can change the region code. Unlike analog television sets, computer monitors can automatically handle both 25 (PAL and SECAM) and 30 (NTSC) frames per second, as well as various picture sizes. This also applies to LCD and plasma "flat panel" television sets, but don't expect their tuner to be compatible outside the country in which they were sold.
• There is no difference between PAL and SECAM for unconverted digital video including DVDs. However, any analog output to a television set would be in the native format of the country of location.
• DVD and Blu-Ray, infuriatingly, have completely artificial limitations introduced in the form of region coding, which attempts to limit the region where the discs can be used, as a technique to keep the various regions as separate markets. For example, a Region 1 player for North America will not play a Region 3 DVD for Hong Kong. The workarounds are to obtain either a region-free player which ignores the code, purchase multi-region discs (Regions 1 and 3 in this case), or better yet, region-free discs (Region 0 for DVDs), which can be played on any device.

Video cameras can usually be charged with both electrical systems so you can record during travels and view it back home. Digital cameras and video cameras can usually output to PAL, NTSC, and SECAM, so you can view your recording while travelling. Output from video cameras is typically composite (yellow RCA jack); you'll likely need an adapter from RCA to either SCART or S-Video to use a European television set.

If you have something on VHS video tape, it's best to convert to DVD before travelling. (Conversions between PAL and NTSC can be done before burning.) Use a video capture card for recording the VHS into a digital file on your computer. Then with DVD-making software, burn the file to a blank DVD.

If required, converting DVDs from one format to another (e.g. PAL to NTSC), can be done on a computer with a fast CPU, or you can get it done professionally. Allow plenty of time, as this can take many hours. Regular blank discs work fine for making copies of a foreign format, as it's all just a bunch of ones and zeros and no different than copying anything else. Copies can be made quickly, while conversions cannot.

Xavfsiz bo'ling

A European (Schuko) socket "killed in action"

The first time you use electrical equipment on a voltage system you haven't used before, watch for excessive heat, strange smells, and smoke. This is especially true for those residing in countries with 120 V (USA, Canada, Japan, etc.) visiting places with the higher voltage. Smoke is a sure sign your equipment cannot cope with the voltage system.

If your electrical equipment gets very hot, smells of burning (there is a distinct smell of electrically fried circuit boards) or starts to smoke, turn it off at the wall, fuse box or the main switch immediately, then carefully unplug the equipment. Do not disconnect or unplug by just grabbing the smoking device, its plug or cord, and then unplugging it, as these parts are probably very hot, and the insulation could be melted or unsafe, which could result in electrocution. Rubber gloves insulate you from current, but not from heat.

You may find your expensive equipment has been fried and needs to be replaced because the wrong voltage was used. However, if the equipment only got hot and did not smoke or produce strange burning smells you may be lucky. Some older devices have fuses that you may be able to replace. New devices, such as gaming consoles, will trip a circuit breaker. Disconnect them from all power and leave them for 60 minutes or so, and the circuit breaker will normally reset. That said, do not rely on fuses to protect your equipment. If a fuse does blow, you should have things checked by an electrician before using the suspect equipment again (unless you're sure that you accidentally plugged in a 120 V device into 240 V power mains).

In countries with frequent blackouts, it's not at all uncommon for a visitor to plug something in and have the power go out coincidentally. Always check the neighborhood first, before blaming the appliance or looking at the fuse/circuit breaker.

Electric shocks

Electric shocks are caused by electricity passing through a human body to earth rather than along the neutral return wire. It should go without saying that electric shocks can kill; at mains voltage, only a very small current (0.03 amps) is needed to interfere with the heart's electrical system and cause the person to enter cardiac arrest.

Damaged or frayed power cords are ripe for causing electric shocks, especially if they come into contact with water. If a power cord becomes frayed or damaged, stop using the appliance immediately and get the cord repaired or replaced.

A residual-current device (RCD) (also known as a ground fault circuit interrupter (GFCI) in the US and Canada) can help prevent electric shocks. It measures the difference in current between the live and neutral wires and if the difference is excessive (suggesting a leakage to earth), the RCD trips off the power. Most new and remodelled homes in developed countries are now required to have RCDs on the distribution board. If you are using an appliance outdoors or in a wet area (e.g. a bathroom), you can buy plug-in RCDs for individual appliances. Some devices such as hair dryers commonly have them already built into the electrical plug.

Power spikes and surges

Power spikes are where the voltage supplied temporarily surges to dangerous levels, with potentially catastrophic consequences. In developed countries, the main source of spikes is weather events such as thunderstorms. in developing countries, they're most often associated with power outages since when the power comes back on, it rarely does so smoothly.

The cheapest method of protection is thus simply to disconnect electronic devices as soon as the power goes out and wait a few minutes after the power comes back on until plugging them back in.

Surge protectors are devices designed specially to protect against spikes and surges, and some are available in portable travel-sized versions. Some surge protectors can also be fitted to a telephone line to protect your phone or laptop modem. The most common variety use a metal oxide varistor (MOV), which shorts to ground if a given voltage is exceeded. These are easily destroyed by larger spikes, and better models will have a light indicating when the MOV has broken down, but you still need to keep an eye on them as the device will still continue to give power even if the protection is gone. There are also surge protectors with fuses, which are fail-safe (a blown fuse will stop power) and replaceable, but there is still a risk of a short, sharp spike which can pass through and damage your device before the fuse blows.

Equipment that switches on and off and has a heavy power draw can also cause surges; fridges and air conditioners are common examples. Even a photocopier drawing different amounts of power as it cycles through pages may produce quite a bit of noise on electrical lines. This is more of a problem for older equipment and buildings than new ones, and more in developing countries than elsewhere.

Voltage drops

In some regions, you may experience electricity voltage drops. This is where the actual voltage less than 90% than the nominal supply voltage (e.g. below 207 V where the nominal voltage is 230 V). In poor regions, voltage drops 50% of the nominal supply voltage is not unknown. This happens especially if you're at "the end of the line" (far from the source or transformer) and is caused by the resistance of the electric lines themselves. Some appliances, such as light bulbs and heating equipment just keep working under a lower voltage, although a 20% voltage drop will cause a 36% power drop. Most electronic devices also keep working, but voltage drops are critical for fluorescent lamps, refrigerators, and air conditioners which may stop working altogether (usually without being damaged: when the voltage returns to normal, they will start working again).

Voltage drops can be solved with a special device called a voltage stabiliser yoki AVR (automatic voltage regulator). A stabiliser will raise the voltage again to its normal level. The principle is the same as for switching converters, except that stabilisers will produce a stable output, even with an unstable input. Stabilisers come in different power ranges, but they're all large, bulky and not practical to carry around. Be aware that some appliances, such as refrigerators, briefly consume two or three times more power at start up; the stabiliser should be able to provide this power. Voltage stabilisers can introduce surges if there is a power outage. The cheaper and most common relay type can also damage electronic equipment.

Blackouts

Blackouts may occur anywhere in the world, though they are more likely in places with lower standard of infrastructure (usually poor countries). Blackouts are not unheard of in developed countries, though there they are mostly caused by extreme weather events or third-party damage (car vs pole, careless digger, etc.). Rural areas are more prone to power outages due to a larger proportion of overhead lines on poles, exposed to the elements, and fewer opportunities to re-route power around a faulty line. Even in first world countries, huge power outages are possible but rare (an example is the 2003 power outage in North America).

A rolling blackout is where different areas are switched off and on in turn as a way of reducing demand. These types of power outages may be common in developing countries. In developed countries, rolling blackouts occur as a last resort where there is insufficient generation, such as after a major power station failure.

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If all else fails...

As stated above, while things like cell phone chargers and electrical shavers (that often get to travel with their owners) nowadays are designed to handle different voltages and frequencies, you have to be much more careful if you're bringing appliances overseas. If you are taking equipment with you that isn't intended for travel use, consider taking a multimeter with you that can handle several hundred volts AC and learn how to use it. With a multimeter you can easily check the voltage in the outlet and don't need to risk the life of your equipment. The ones with a digital display are easier to read and a few are as compact as a small pocket calculator.