All four units generate power at 13.8 kilovolts (kV). Electricity was generated at 17 kilovolts (kV). High-tension powerlines often operate in the range of tens to hundreds of kilovolts. The accelerator voltage is normally between 80 and 180 kilovolts. For certain current transformers, this voltage may reach several kilovolts and may cause arcing. The DC systems in the USSR had a nominal voltage of 3 kilovolts. A positive voltage of 5 to 10 kilovolts is applied to the tip. The ion source voltage is normally between 2 and 7 kilovolts. The line used three-phase current at 10 kilovolts and 45 Hz. Acceleration energies for gases such as argon are typically a few kilovolts. CEMs required 2-4 kilovolts in order to achieve a gain of 10 electrons. Its plant at Axat-Saint-Georges supplied the cities of Carcassonne and Narbonne at 20 kilovolts. Semiconductor devices exist with ratings up to a few kilovolts in a single device.