Reforming Electrolytic Capacitors Power Supply

6 min read Jun 26, 2024
Reforming Electrolytic Capacitors Power Supply

Reforming Electrolytic Capacitors in Power Supplies: A Comprehensive Guide


Electrolytic capacitors are a crucial component in power supplies, responsible for filtering and regulating the output voltage. Over time, however, these capacitors can deteriorate, leading to reduced performance, instability, and even complete power supply failure. One way to revitalize these capacitors is through a process called reforming. In this article, we will explore the concept of reforming electrolytic capacitors in power supplies, its benefits, and the step-by-step process to do it safely and effectively.

What is Capacitor Reforming?

Capacitor reforming is a process that restores the original capacitance and reduces the equivalent series resistance (ESR) of an electrolytic capacitor. This is achieved by applying a controlled voltage and current to the capacitor, slowly rebuilding the oxide layer and reversing the effects of aging.

Why Reform Electrolytic Capacitors?

Reforming electrolytic capacitors in power supplies offers several benefits, including:

Improved Performance

Reformed capacitors can restore the original performance of the power supply, ensuring stable output voltages and reduced ripple.

Extended Lifespan

Reforming can extend the lifespan of electrolytic capacitors, delaying the need for replacement and reducing maintenance costs.

Reduced Downtime

By reforming capacitors, power supply downtime can be minimized, ensuring continuous operation and reducing the risk of unexpected failures.

The Reforming Process

Reforming electrolytic capacitors requires caution and attention to detail to avoid damaging the components. Here is a step-by-step guide to reforming electrolytic capacitors in power supplies:

Step 1: Identify the Capacitors to be Reformed

Identify the electrolytic capacitors in the power supply that require reforming. Check the capacitor's voltage rating, capacitance value, and ESR to determine if reforming is necessary.

Step 2: Discharge the Capacitors

Disconnect the power supply from the load and discharge the capacitors using a suitable resistor or discharging device. Verify that the capacitor voltage has dropped to a safe level before proceeding.

Step 3: Set up the Reforming Circuit

Create a reforming circuit consisting of a variable voltage power supply, a current limiter, and a voltage regulator. The reforming voltage should be set to approximately 10-20% of the capacitor's rated voltage.

Step 4: Apply the Reforming Voltage

Connect the reforming circuit to the capacitor and slowly apply the reforming voltage. Monitor the capacitor's voltage and current to ensure that it remains within safe limits.

Step 5: Gradually Increase the Voltage

Gradually increase the reforming voltage over a period of several hours or days, while monitoring the capacitor's voltage and current.

Step 6: Verify the Results

Once the reforming process is complete, verify the capacitor's performance using a capacitance meter and ESR meter. Compare the results to the original specifications to ensure that the reforming process was successful.

Safety Precautions

Reforming electrolytic capacitors requires caution to avoid electrical shock, capacitor damage, and even fire. Always follow proper safety procedures, including:

Use Protective Equipment

Wear protective equipment, such as safety glasses and insulating gloves, to prevent electrical shock.

** Ensure a Safe Working Environment**

Work in a well-ventilated area, away from flammable materials, and ensure that the workspace is clear of any obstacles.

Follow Proper Procedures

Carefully follow the reforming process, avoiding sudden changes in voltage or current that can damage the capacitor.


Reforming electrolytic capacitors in power supplies is a cost-effective and efficient way to revitalize degraded capacitors, ensuring stable output voltages and extended lifespan. By following the step-by-step process outlined in this article, you can safely and effectively reform electrolytic capacitors, minimizing downtime and reducing maintenance costs. Remember to always prioritize safety and follow proper procedures to avoid electrical shock and capacitor damage.