倍压器（voltage doubler）是提升电压的电路，利用输入电压将电容器充电，并且利用电路的切换，在理想情形下，可以使电容器的电压恰为输入电压的二倍。

最简单的倍压器是一种特殊的整流器，输入是交流电压，输出是两倍的直流电压，其切换组件为二极管，其切换只是因着输入电压的正负电压变化而切换导通或关闭。直流－直流的倍压器像交流－直流的倍压器，只是根据输入电压的正负变化而进行切换，需要驱动电路来控制其切换，多半也需要可受控的切换组件，例如晶体管。

倍压器是多倍压器电路的一种变形，许多（不过不是所有）的倍压器可以视为高倍率倍压器中的一级，若组合数个倍压器，可以达到更高的倍率。

A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input.

The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching. They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case.