Disclosed are methods for preparing dried preparations comprising a population of alphaviruses or alphavirus replicon particles, a sugar or polyol, a surfactant and a salt and preparations made by these methods, both in the dried form but also as liquids prior to drying or after reconstituting dried preparations. The dynamic voltage focusing electrode and the stem pin are connected and the wire for applying the dynamic voltage is formed to a twisted several-strand wires to thereby improve the damping coefficient. The power supply for the electronic device preferably includes N1 power supplies where N power supplies are required by the electronic device. The adder adds together the signals output from the splitter. The method comprises detecting that the device is attached to a charging port, and determining whether the charging port is the CDP or the DCP without causing a host coupled to the CDP to be able to detect the device if the charging port is the CDP.