How To Test A High Voltage Capacitor With A Multimeter

5 min read Jun 26, 2024
How To Test A High Voltage Capacitor With A Multimeter

How to Test a High Voltage Capacitor with a Multimeter

Safety Precautions

Warning: High Voltage Capacitors can be Deadly!

Before attempting to test a high voltage capacitor, make sure you understand the risks involved. High voltage capacitors can store a lethal amount of electrical energy, and improper handling can result in serious injury or even death.

Ensure You Follow These Safety Precautions:

  • Disconnect the capacitor from the circuit: Make sure the capacitor is not connected to any power source or circuit before testing.
  • Use protective gear: Wear insulated gloves, safety glasses, and a face shield to protect yourself from electrical shock.
  • Choose the right multimeter: Select a multimeter that is rated for high voltage measurements and has a high enough voltage range to accommodate the capacitor's voltage rating.
  • Follow proper testing procedures: Avoid touching the capacitor's terminals or any metal parts with your bare hands.

Testing a High Voltage Capacitor with a Multimeter

Step 1: Identify the Capacitor's Ratings

Before testing, identify the capacitor's voltage rating, capacitance value, and tolerance. This information is usually printed on the capacitor's body or in the datasheet.

Step 2: Choose the Right Multimeter Range

Set your multimeter to the voltage range that is higher than the capacitor's voltage rating. For example, if the capacitor is rated for 1000V, set the multimeter to the 1500V or 2000V range.

Step 3: Connect the Multimeter Leads

Connect the multimeter leads to the capacitor's terminals. Make sure the leads are securely connected and not touching any other metal parts.

Step 4: Measure the Capacitor's Voltage

Measure the capacitor's voltage using the multimeter. The reading should be close to zero if the capacitor is fully discharged. If the reading is not zero, it may indicate that the capacitor is still charged and should be discharged before proceeding.

Step 5: Measure the Capacitor's Capacitance

Set the multimeter to the capacitance measurement function (usually denoted by the "C" or "CAP" symbol). Measure the capacitor's capacitance value and compare it to the rated value. A significant deviation from the rated value may indicate a faulty capacitor.

Step 6: Perform a leakage Test (Optional)

To test for leakage, set the multimeter to the voltage measurement function and connect the leads to the capacitor's terminals. Apply a voltage slightly lower than the capacitor's rated voltage using an external power source (e.g., a variable power supply). Measure the current flowing through the capacitor using the multimeter. A high current reading may indicate a leaking capacitor.


Testing a high voltage capacitor with a multimeter requires caution and attention to safety precautions. By following these steps, you can ensure a safe and accurate measurement of the capacitor's voltage, capacitance, and leakage. Remember to always handle high voltage capacitors with care and respect their potential to cause harm.