Reforming Electrolytic Capacitors

4 min read Jun 26, 2024
Reforming Electrolytic Capacitors

Reforming Electrolytic Capacitors: Understanding the Process

Electrolytic capacitors are widely used in electronic circuits due to their high capacitance values and small size. However, over time, these capacitors can become degraded, leading to reduced performance and eventually, failure. One way to restore the performance of electrolytic capacitors is through the process of reforming. In this article, we will delve into the world of reforming electrolytic capacitors, exploring the reasons behind capacitor degradation, the reforming process, and its benefits.

Why Do Electrolytic Capacitors Degrade?

Electrolytic capacitors degrade due to various factors, including:

** Oxidation **

When an electrolytic capacitor is not used for an extended period, the electrolyte can evaporate, leading to oxidation of the aluminum foil. This oxidation causes the capacitor's capacitance to decrease, and its equivalent series resistance (ESR) to increase.

** Moisture Absorption **

Moisture can seep into the capacitor, causing the electrolyte to break down and leading to a decrease in capacitance and an increase in ESR.

** High Temperatures **

Operating electrolytic capacitors at high temperatures can cause the electrolyte to degrade, leading to a decrease in capacitance and an increase in ESR.

The Reforming Process

Reforming electrolytic capacitors involves applying a controlled voltage to the capacitor to restore its performance. The process involves several stages:

Initial Reforming Stage

A low voltage (typically 10-20% of the rated voltage) is applied to the capacitor to help the electrolyte to relax and redistribute.

Voltage Ramp-Up Stage

The voltage is gradually increased to the rated voltage, allowing the electrolyte to reform and the capacitor to recover its original performance.

Reforming Cycle

The reforming process involves repeating the initial reforming stage and voltage ramp-up stage several times to ensure the capacitor is fully reformed.

Benefits of Reforming Electrolytic Capacitors

Reforming electrolytic capacitors offers several benefits, including:

Restored Performance

Reforming can restore the capacitor's original performance, including its capacitance value and ESR.

Extended Lifespan

Reforming can extend the lifespan of electrolytic capacitors, making them suitable for use in critical applications.


Reforming is a cost-effective way to restore the performance of electrolytic capacitors, eliminating the need for replacement.


Reforming electrolytic capacitors is a useful technique for restoring the performance of degraded capacitors. By understanding the reasons behind capacitor degradation and the reforming process, engineers can effectively restore the performance of electrolytic capacitors, extending their lifespan and reducing costs.