Best Answer: charge is an excess or deficit of electrons. It is measured in coulombs. voltage is measured in volts. Voltage is the potential difference measured between two points. a diode is an electronic device that conducts current only in one direction. no-load voltage is the voltage without any load. ..defined by Coulomb’s law. If an electric force of one unit (one dyne) arises between two equal electric charges one centimetre apart in a vacuum, the amount of each charge is one electrostatic unit, esu, or statcoulomb.