Testing Ac Capacitor With Ohm Meter

5 min read Jun 26, 2024
Testing Ac Capacitor With Ohm Meter

Testing an AC Capacitor with an Ohm Meter


When it comes to troubleshooting and repairing electrical circuits, testing the capacitors is an essential step. Capacitors are an crucial component in many electronic devices, and their failure can cause a range of problems. In this article, we will discuss how to test an AC capacitor using an ohm meter.

What is an AC Capacitor?

An AC capacitor, also known as a non-polarized capacitor, is a type of capacitor that is designed to operate with alternating current (AC) voltage. It is commonly used in power supplies, audio equipment, and other electronic devices. AC capacitors are designed to handle the high voltage and frequency of AC power, and they are typically larger and more robust than DC capacitors.

Why Test an AC Capacitor?

Testing an AC capacitor is important because it can fail due to various reasons, such as:

  • Overvoltage: Excessive voltage can cause the capacitor to break down and fail.
  • Overheating: High temperatures can cause the capacitor to degrade and fail.
  • Physical Damage: Physical stress, such as vibration or shock, can cause the capacitor to fail.

How to Test an AC Capacitor with an Ohm Meter

Testing an AC capacitor with an ohm meter is a relatively simple process. Here are the steps to follow:

Step 1: Disconnect the Capacitor

Before testing the capacitor, make sure to disconnect it from the circuit. This is important to prevent any accidental short circuits or electrical shocks.

Step 2: Set the Ohm Meter

Set the ohm meter to the highest ohm range (usually 1 Mohm or higher).

Step 3: Connect the Leads

Connect the ohm meter leads to the capacitor terminals. Make sure to connect the leads correctly, with the positive lead connected to the positive terminal and the negative lead connected to the negative terminal.

Step 4: Take the Reading

Take the ohm reading by switching on the ohm meter. The reading should be infinite (open circuit) or very high (>1 Mohm).

Step 5: Check for Continuity

To check for continuity, set the ohm meter to the lowest ohm range (usually 200 ohm or lower). If the capacitor is good, the reading should be very low (<1 ohm). If the reading is high, it may indicate a faulty capacitor.

Interpreting the Results

Here are some possible results and their interpretations:

  • Infinite Reading: The capacitor is good and functioning correctly.
  • High Reading: The capacitor may be faulty or damaged.
  • Low Reading: The capacitor may be short-circuited or leaky.


Testing an AC capacitor with an ohm meter is a simple and essential step in troubleshooting and repairing electrical circuits. By following the steps outlined in this article, you can quickly and easily determine whether an AC capacitor is functioning correctly. Remember to always exercise caution when working with electrical circuits, and never touch electrical components with your bare hands.