Testing Continuity in Circuit Using Digital Multimeter - Electronics LAB

Multimeters are a very useful tool for diagnosing problems with electrical systems. They are simple to use when you know how! I use my fluke multimeter nearly once a week to try and fix problems with electronic devices at home. One of the most basic uses of a multimeter is to test for continuity. Testing for continuity basically means testing to see if there is an electric connection between two points. If two points are electrically connected they are said to be continuous. This brief guide explains how to use a digital multimeter to find out if there is an electric connection between two points. 

Getting Ready 
Before you test for an electric connection you must do a few things:


- Make sure your multimeter is working. You can test this by brushing the two tips together and verifying that you hear a beep. The manual you received with your multimeter may have more information on testing your multimeter. 

- Make sure the device or system you are testing is powered off. If there is already voltage in the circuit you will not get accurate readings. 


Steps 
When you are ready to test for continuity follow these steps in this order: 
1. Set your multimeter to the correct mode. Look for the icon that looks like a sound wave or a Wi-Fi connection indicator. If you can't find it refer to the manual you received with the multimeter. 

2. Touch one of the probes off one of the points you are checking. 

3. Touch the other probe off the other point. 

4. If you hear a beep or a buzz, there is an electric connection between the two points. 

5. If there is not an electric connection you will not hear a beep or a buzz and the display will give a reading of 0. 

Uses For Continuity Testing
Continuity testing can help you test your soldered connections to see if they were soldered correctly. A beginner who is not experienced in visually detecting problems with a soldered joint can get frustrated very easily because a joint can look like its soldered correctly but there may be no electric connection. Using a multimeter can quickly help you find out if the soldered connection is good or not.

This test can also help you determine if a wire is broken in the middle. I recently had a problem with a pair of earphones. By testing with a multimeter I could see that there was no electrical current flowing between the ear bud and the iPod connection and this told me that the wire was broken somewhere in the middle…probably my fault for leaving the iPod in the bottom of my bag!


Another basic use for continuity testing is to test if a short circuit has been created. You can use the multimeter to confirm that two points are not electrically connected and that a short circuit does not exist.

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Multimeter: Testing AC Voltage

Testing DC Voltage
Testing Continuity
Testing Resistors
Measuring Current
Testing Diodes/LED (Light Emitting Diodes)

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