Jännitekerrointa

Jännitekerroin, known in English as voltage multiplier, is an electrical circuit that produces a high direct current (DC) voltage from a lower alternating current (AC) or DC input. It consists of a cascade of diodes and capacitors arranged in such a way that the peak voltage of the AC input is successively multiplied. This arrangement allows for the generation of significantly higher voltages than could be achieved with simple rectification.

The fundamental principle behind a voltage multiplier is the charging of capacitors to a certain voltage level and then discharging them in series. In a typical half-wave voltage doubler, for example, a capacitor is charged to the peak AC voltage during one half-cycle, and then in the next half-cycle, another diode and capacitor combination adds this charged voltage to the incoming AC voltage, effectively doubling it. More complex multipliers, such as Cockcroft-Walton generators, extend this principle with multiple stages to achieve much higher voltage multiplication factors.

Voltage multipliers are utilized in various applications where a high DC voltage is required but a simpler transformer-based solution is impractical or too expensive. Examples include cathode ray tube (CRT) displays for accelerating electrons, electrostatic generators, high-voltage power supplies for scientific instruments, and in some types of laser power supplies. Their advantage lies in their ability to generate high voltages without the need for bulky and heavy transformers, making them suitable for compact designs. However, they also have limitations, such as ripple in the output voltage and potential for significant current draw, which can affect their efficiency and stability.