An electrolytic capacitor placed in series between a power transformer and rectifiers is commonly used to create a voltage doubler circuit. In this arrangement, the capacitor helps to increase the output voltage by effectively storing and releasing charge in a manner that allows for the doubling of the AC waveform's peak voltage.
When the AC voltage from the transformer is rectified, the capacitor behaves differently depending on the phase of the AC cycle. During one half of the cycle, it charges up to the peak voltage, and during the next half-cycle, it is able to discharge this accumulated voltage, effectively adding its charge to the next peak of the incoming AC. This leads to a higher overall voltage available at the output than would be obtained from the transformer alone.
This function is crucial in systems where a higher DC output voltage is required than what the transformer can provide, making the capacitor's role essential for the design and operation of voltage doubler circuits. The details of this operation illustrate how capacitors can interact with AC signals and achieve specific outcomes in power conversion applications.