Biàn / yā / qì / de / tiě / xīn / tōng / cháng / yóu / xǔ / duō / céng / guī / gāng / piàn / zǔ / chéng变压器的铁芯通常由许多层硅钢片组成。A transformer's iron core is usually made of many layers of silicon steel sheets.