mˈoʊst sˈɪŋɡəl fˈeɪz ˈɔːltɚnˌeɪɾɪŋkˈɜːɹənt ᵻlˈɛktɹɪkəl ˈaʊtlɛts ɪnðə wˈɜːld səplˈaɪ pˈaʊɚɹ æt tˈuːhˈʌndɹɪd tˈɛn tˈuːhˈʌndɹɪd fˈoːɹɾi vˈiː ɔːɹ æt wˈʌnhˈʌndɹɪd wˈʌnhˈʌndɹɪd twˈɛnti vˈiː. ɐ tɹænsfˈoːɹmɚ ɔːɹ ˌɔːɾoʊtɹænsfˈoːɹmɚ kæn biː jˈuːzd; ˈɔːɾoʊ tɹænsfˈoːɹmɚz ɑːɹ ɪnhˈiəɹəntli ɹᵻvˈɜːsᵻbəl, sˌoʊ ðə sˈeɪm tɹænsfˈoːɹmɚ kæn biː jˈuːzd tə stˈɛp ðə vˈoʊltɪdʒ ˈʌp, ɔːɹ stˈɛp ɪt dˌaʊn baɪ ðə sˈeɪm ɹˈeɪʃɪˌoʊ.
Most single phase alternating-current electrical outlets in the world supply power at 210–240 V or at 100–120 V. A transformer or autotransformer can be used; (auto)transformers are inherently reversible, so the same transformer can be used to step the voltage up, or step it down by the same ratio.