Mene ne halayyar impedance

Daya daga cikin sigogi ne wani conductive line halayyar impedance. Na musamman munasaba da ta samu a high-mita rediyo watsa dabara, inda wata 'yar alamar mismatch kewaye aiki take kaiwa zuwa gagarumin hargitsi a cikin fitarwa. A daya hannun, kowane mariƙin na kwamfuta hade da sauran a wani gida cibiyar sadarwa, na fuskantar kullum Kalmar "halayyar impedance." Ya kamata a lura cewa bayyanar Ethernet networks na Twisted biyu bada karshen mai amfani ba damu game da musamman haši, earthing, kamar yadda haši da terminators, kamar yadda shi ne yanayin da coaxial na USB Lines 10 megabit (ko kasa). Duk da haka, ko da tare da girmamawa ga Twisted biyu, da kalmar "halayyar impedance" ne m. Kullum, a cikin aiki na kwamfuta cibiyoyin sadarwa musamman alama daga baya.

Saboda haka, abin da yake halayyar impedance? Kamar yadda riga ya bayyana, wannan shi ne daya daga cikin halaye na conductive Lines a kan tushen da ƙarfe conductors. A karshe kashi zama dole domin kada su Mix zamani Tantancewar watsa bayanai Lines da classic jan wayoyi, wanda suke da makamashi dako ba caje barbashi da kuma haske - akwai wasu dokoki. Wannan darajar nuna wani layi da ciwon da juriya darajar janareta (source modulated lantarki oscillations). Kada dame juriya, wanda za a iya auna da al'ada multimeter, da kuma halayyar impedance na yanayi, kamar yadda su ne gaba daya daban-daban abubuwa. A karshen ba ya dogara ne a kan tsawon da shugaba (wannan shi ne riga isa ya zana karshe game da "kama" na juriya). Jiki, shi ne daidai da square tushen daga cikin rabo na inductance (Henry) to damar (Farad). A kananan ra'ayi: duk da cewa lissafin amfani amsawa aka gyara daga cikin line, da kalaman da juriya da kewaye ne ko da yaushe a cikin lissafin aka dauke aiki.

Shi ne mafi kyau ga la'akari da duk da misali. Tunanin wani sauki kewaye kunshi wani ikon source (janareta, R1), da conductors ciwon halayyar impedance (R2), da kuma mabukaci (load, R3). A hali na daidaitakar dukan uku resistances duk daukar kwayar cutar makamashi kai mabukaci da kuma shi aikin amfani aiki. Idan a wani bangare na wannan lissafi ba gamsu, akwai wani mismatched aiki. A wurin da layin ta kakkarye, akwai wani nuna kalaman, kuma wani rabo daga electromagnetic makamashi zo da baya - to da janareta. Haka kuma, wajibi ne a kara yawan ikon rama domin girma na nuna makamashi. A wasu kalmomin, wani ɓangare na samar da makamashi da aka kashe "kome ba", wanda ke nufin asarar da kuma wadanda ba mafi kyau duka aiki. Bugu da kari, a wasu lokuta, da mismatch kullum disrupts aiki na dukan line.

Yanzu baya ga kwamfuta cibiyar sadarwa, inda kalaman juriya taka muhimmiyar rawa. Domin Lines dangane da coaxial na USB (50 ohm) ne mai muhimmanci ga mutunta yanayi: juriya cibiyar sadarwa katunan da shugaba tsakanin su ya zama daidai. Kawai a cikin wannan harka, aiki karewa da kuma grounding tsarin. Idan wani sashi na USB line ne jiki kadan stretch (rataya a load shugaba), sa'an nan saboda canje-canje a cikin diamita na conductors a wannan wuri zai canza halayyar impedance, akwai za a nuna kalaman, watse saukar da tsarin. A wannan yanayin da auna aiki da juriya line iya canja ba ma (low cost na'urorin ba rajistar karuwa a juriya). Kokarin mayar da layin conductors da soldering a kan lalace rabo kara tsananta halin da ake ciki, domin shi zai ba kawai canza wurin juriya, da kuma cakuda daban-daban yanayin (tin, jan) a cikin abin da taguwar ruwa propagate daban.

Kamar yadda rare kamar yadda a Twisted biyu category 5 halayyar impedance ne 100 ohms. Godiya ga wannan dawo iya soldered, kuma ko da karkatarwa.