Before revision: A high-voltage power supply powered by mains electricity , which may be a simple transformerless voltage multiplier circuit made with diodes and capacitors , generates a voltage of 2 kilovolts or more , .
After revision: A high-voltage power supply powered by wall power is used , which may be a simple transformerless voltage multiplier circuit made with diodes and capacitors which can generate a voltage of 2 kilovolts or more .