ɐksˈɛlɚɹˌeɪɾɪŋ vˈoʊltɪdʒᵻz kæn biː bᵻtwˌiːn θɹˈiː ænd fˈoːɹɾi kˈeɪ vˈiː. wˌɛn ðɪ ɐksˈɛlɚɹˌeɪɾɪŋ vˈoʊltɪdʒ ɪz twˈɛnti twˈɛnti fˈaɪv kˈeɪ vˈiː ænd ðə bˈiːm kˈɜːɹənt ɪz ɐ fjˈuː ˈæmpɛɹz, ˈeɪɾi fˈaɪv pɚsˈɛnt ʌvðɪ ᵻlˈɛktɹɑːnz kᵻnˈɛɾɪk ˈɛnɚdʒi kæn biː kənvˈɜːɾᵻd ˌɪntʊ θˈɜːməl ˈɛnɚdʒi.
Accelerating voltages can be between 3 and 40 kV. When the accelerating voltage is 20–25 kV and the beam current is a few amperes, 85% of the electron's kinetic energy can be converted into thermal energy.