Allolin da aka buga, wanda kuma ake kira Printed Circuit Boards, haɗin wutar lantarki ne don kayan lantarki.

Ana kiran allunan da'ira da aka buga da yawa a matsayin "PCB" fiye da "hudumar PCB".

Ya kasance a cikin ci gaba fiye da shekaru 100;Tsarinsa shine ƙirar shimfidar wuri;Babban fa'idar hukumar kewayawa ita ce rage girman wayoyi da kurakuran taro, haɓaka matakin sarrafa kansa da ƙimar ma'aikata.

Dangane da adadin layuka na allon kewayawa, ana iya raba shi zuwa guda ɗaya, panel biyu, yadudduka huɗu, yadudduka shida da sauran yadudduka na allon kewaye.

Saboda bugu na da'ira ba kayayyakin gama gari na gama gari ba, akwai wasu ruɗani a cikin ma'anar sunan.Misali, ana amfani da allon uwa a cikin kwamfutoci na sirri ana kiran shi babban allo kuma ba za a iya kiran shi kai tsaye da da'ira ba.Duk da cewa akwai allunan kewayawa a cikin babban allon, ba iri ɗaya ba ne.Wani misali kuma: domin akwai hadedde abubuwan da aka ɗora a kan allon kewayawa, don haka kafofin watsa labaru suna kiranta IC board, amma a zahiri ba ɗaya yake da na'urar da aka buga ba.Lokacin da muke magana game da allunan da’ira, yawanci muna nufin allunan da’ira waɗanda ba su da abubuwan farko.